WIP FPC-III support

[linux/fpc-iii.git] / drivers / net / dsa / vitesse-vsc73xx-core.c

// SPDX-License-Identifier: GPL-2.0
/* DSA driver for:
 * Vitesse VSC7385 SparX-G5 5+1-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7388 SparX-G8 8-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7395 SparX-G5e 5+1-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7398 SparX-G8e 8-port Integrated Gigabit Ethernet Switch
 *
 * These switches have a built-in 8051 CPU and can download and execute a
 * firmware in this CPU. They can also be configured to use an external CPU
 * handling the switch in a memory-mapped manner by connecting to that external
 * CPU's memory bus.
 *
 * Copyright (C) 2018 Linus Wallej <linus.walleij@linaro.org>
 * Includes portions of code from the firmware uploader by:
 * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
#include <linux/bitops.h>
#include <linux/if_bridge.h>
#include <linux/etherdevice.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/random.h>
#include <net/dsa.h>

#include "vitesse-vsc73xx.h"

#define VSC73XX_BLOCK_MAC       0x1 /* Subblocks 0-4, 6 (CPU port) */
#define VSC73XX_BLOCK_ANALYZER  0x2 /* Only subblock 0 */
#define VSC73XX_BLOCK_MII       0x3 /* Subblocks 0 and 1 */
#define VSC73XX_BLOCK_MEMINIT   0x3 /* Only subblock 2 */
#define VSC73XX_BLOCK_CAPTURE   0x4 /* Only subblock 2 */
#define VSC73XX_BLOCK_ARBITER   0x5 /* Only subblock 0 */
#define VSC73XX_BLOCK_SYSTEM    0x7 /* Only subblock 0 */

#define CPU_PORT        6 /* CPU port */

/* MAC Block registers */
#define VSC73XX_MAC_CFG         0x00
#define VSC73XX_MACHDXGAP       0x02
#define VSC73XX_FCCONF          0x04
#define VSC73XX_FCMACHI         0x08
#define VSC73XX_FCMACLO         0x0c
#define VSC73XX_MAXLEN          0x10
#define VSC73XX_ADVPORTM        0x19
#define VSC73XX_TXUPDCFG        0x24
#define VSC73XX_TXQ_SELECT_CFG  0x28
#define VSC73XX_RXOCT           0x50
#define VSC73XX_TXOCT           0x51
#define VSC73XX_C_RX0           0x52
#define VSC73XX_C_RX1           0x53
#define VSC73XX_C_RX2           0x54
#define VSC73XX_C_TX0           0x55
#define VSC73XX_C_TX1           0x56
#define VSC73XX_C_TX2           0x57
#define VSC73XX_C_CFG           0x58
#define VSC73XX_CAT_DROP        0x6e
#define VSC73XX_CAT_PR_MISC_L2  0x6f
#define VSC73XX_CAT_PR_USR_PRIO 0x75
#define VSC73XX_Q_MISC_CONF     0xdf

/* MAC_CFG register bits */
#define VSC73XX_MAC_CFG_WEXC_DIS        BIT(31)
#define VSC73XX_MAC_CFG_PORT_RST        BIT(29)
#define VSC73XX_MAC_CFG_TX_EN           BIT(28)
#define VSC73XX_MAC_CFG_SEED_LOAD       BIT(27)
#define VSC73XX_MAC_CFG_SEED_MASK       GENMASK(26, 19)
#define VSC73XX_MAC_CFG_SEED_OFFSET     19
#define VSC73XX_MAC_CFG_FDX             BIT(18)
#define VSC73XX_MAC_CFG_GIGA_MODE       BIT(17)
#define VSC73XX_MAC_CFG_RX_EN           BIT(16)
#define VSC73XX_MAC_CFG_VLAN_DBLAWR     BIT(15)
#define VSC73XX_MAC_CFG_VLAN_AWR        BIT(14)
#define VSC73XX_MAC_CFG_100_BASE_T      BIT(13) /* Not in manual */
#define VSC73XX_MAC_CFG_TX_IPG_MASK     GENMASK(10, 6)
#define VSC73XX_MAC_CFG_TX_IPG_OFFSET   6
#define VSC73XX_MAC_CFG_TX_IPG_1000M    (6 << VSC73XX_MAC_CFG_TX_IPG_OFFSET)
#define VSC73XX_MAC_CFG_TX_IPG_100_10M  (17 << VSC73XX_MAC_CFG_TX_IPG_OFFSET)
#define VSC73XX_MAC_CFG_MAC_RX_RST      BIT(5)
#define VSC73XX_MAC_CFG_MAC_TX_RST      BIT(4)
#define VSC73XX_MAC_CFG_CLK_SEL_MASK    GENMASK(2, 0)
#define VSC73XX_MAC_CFG_CLK_SEL_OFFSET  0
#define VSC73XX_MAC_CFG_CLK_SEL_1000M   1
#define VSC73XX_MAC_CFG_CLK_SEL_100M    2
#define VSC73XX_MAC_CFG_CLK_SEL_10M     3
#define VSC73XX_MAC_CFG_CLK_SEL_EXT     4

#define VSC73XX_MAC_CFG_1000M_F_PHY     (VSC73XX_MAC_CFG_FDX | \
                                         VSC73XX_MAC_CFG_GIGA_MODE | \
                                         VSC73XX_MAC_CFG_TX_IPG_1000M | \
                                         VSC73XX_MAC_CFG_CLK_SEL_EXT)
#define VSC73XX_MAC_CFG_100_10M_F_PHY   (VSC73XX_MAC_CFG_FDX | \
                                         VSC73XX_MAC_CFG_TX_IPG_100_10M | \
                                         VSC73XX_MAC_CFG_CLK_SEL_EXT)
#define VSC73XX_MAC_CFG_100_10M_H_PHY   (VSC73XX_MAC_CFG_TX_IPG_100_10M | \
                                         VSC73XX_MAC_CFG_CLK_SEL_EXT)
#define VSC73XX_MAC_CFG_1000M_F_RGMII   (VSC73XX_MAC_CFG_FDX | \
                                         VSC73XX_MAC_CFG_GIGA_MODE | \
                                         VSC73XX_MAC_CFG_TX_IPG_1000M | \
                                         VSC73XX_MAC_CFG_CLK_SEL_1000M)
#define VSC73XX_MAC_CFG_RESET           (VSC73XX_MAC_CFG_PORT_RST | \
                                         VSC73XX_MAC_CFG_MAC_RX_RST | \
                                         VSC73XX_MAC_CFG_MAC_TX_RST)

/* Flow control register bits */
#define VSC73XX_FCCONF_ZERO_PAUSE_EN    BIT(17)
#define VSC73XX_FCCONF_FLOW_CTRL_OBEY   BIT(16)
#define VSC73XX_FCCONF_PAUSE_VAL_MASK   GENMASK(15, 0)

/* ADVPORTM advanced port setup register bits */
#define VSC73XX_ADVPORTM_IFG_PPM        BIT(7)
#define VSC73XX_ADVPORTM_EXC_COL_CONT   BIT(6)
#define VSC73XX_ADVPORTM_EXT_PORT       BIT(5)
#define VSC73XX_ADVPORTM_INV_GTX        BIT(4)
#define VSC73XX_ADVPORTM_ENA_GTX        BIT(3)
#define VSC73XX_ADVPORTM_DDR_MODE       BIT(2)
#define VSC73XX_ADVPORTM_IO_LOOPBACK    BIT(1)
#define VSC73XX_ADVPORTM_HOST_LOOPBACK  BIT(0)

/* CAT_DROP categorizer frame dropping register bits */
#define VSC73XX_CAT_DROP_DROP_MC_SMAC_ENA       BIT(6)
#define VSC73XX_CAT_DROP_FWD_CTRL_ENA           BIT(4)
#define VSC73XX_CAT_DROP_FWD_PAUSE_ENA          BIT(3)
#define VSC73XX_CAT_DROP_UNTAGGED_ENA           BIT(2)
#define VSC73XX_CAT_DROP_TAGGED_ENA             BIT(1)
#define VSC73XX_CAT_DROP_NULL_MAC_ENA           BIT(0)

#define VSC73XX_Q_MISC_CONF_EXTENT_MEM          BIT(31)
#define VSC73XX_Q_MISC_CONF_EARLY_TX_MASK       GENMASK(4, 1)
#define VSC73XX_Q_MISC_CONF_EARLY_TX_512        (1 << 1)
#define VSC73XX_Q_MISC_CONF_MAC_PAUSE_MODE      BIT(0)

/* Frame analyzer block 2 registers */
#define VSC73XX_STORMLIMIT      0x02
#define VSC73XX_ADVLEARN        0x03
#define VSC73XX_IFLODMSK        0x04
#define VSC73XX_VLANMASK        0x05
#define VSC73XX_MACHDATA        0x06
#define VSC73XX_MACLDATA        0x07
#define VSC73XX_ANMOVED         0x08
#define VSC73XX_ANAGEFIL        0x09
#define VSC73XX_ANEVENTS        0x0a
#define VSC73XX_ANCNTMASK       0x0b
#define VSC73XX_ANCNTVAL        0x0c
#define VSC73XX_LEARNMASK       0x0d
#define VSC73XX_UFLODMASK       0x0e
#define VSC73XX_MFLODMASK       0x0f
#define VSC73XX_RECVMASK        0x10
#define VSC73XX_AGGRCTRL        0x20
#define VSC73XX_AGGRMSKS        0x30 /* Until 0x3f */
#define VSC73XX_DSTMASKS        0x40 /* Until 0x7f */
#define VSC73XX_SRCMASKS        0x80 /* Until 0x87 */
#define VSC73XX_CAPENAB         0xa0
#define VSC73XX_MACACCESS       0xb0
#define VSC73XX_IPMCACCESS      0xb1
#define VSC73XX_MACTINDX        0xc0
#define VSC73XX_VLANACCESS      0xd0
#define VSC73XX_VLANTIDX        0xe0
#define VSC73XX_AGENCTRL        0xf0
#define VSC73XX_CAPRST          0xff

#define VSC73XX_MACACCESS_CPU_COPY              BIT(14)
#define VSC73XX_MACACCESS_FWD_KILL              BIT(13)
#define VSC73XX_MACACCESS_IGNORE_VLAN           BIT(12)
#define VSC73XX_MACACCESS_AGED_FLAG             BIT(11)
#define VSC73XX_MACACCESS_VALID                 BIT(10)
#define VSC73XX_MACACCESS_LOCKED                BIT(9)
#define VSC73XX_MACACCESS_DEST_IDX_MASK         GENMASK(8, 3)
#define VSC73XX_MACACCESS_CMD_MASK              GENMASK(2, 0)
#define VSC73XX_MACACCESS_CMD_IDLE              0
#define VSC73XX_MACACCESS_CMD_LEARN             1
#define VSC73XX_MACACCESS_CMD_FORGET            2
#define VSC73XX_MACACCESS_CMD_AGE_TABLE         3
#define VSC73XX_MACACCESS_CMD_FLUSH_TABLE       4
#define VSC73XX_MACACCESS_CMD_CLEAR_TABLE       5
#define VSC73XX_MACACCESS_CMD_READ_ENTRY        6
#define VSC73XX_MACACCESS_CMD_WRITE_ENTRY       7

#define VSC73XX_VLANACCESS_LEARN_DISABLED       BIT(30)
#define VSC73XX_VLANACCESS_VLAN_MIRROR          BIT(29)
#define VSC73XX_VLANACCESS_VLAN_SRC_CHECK       BIT(28)
#define VSC73XX_VLANACCESS_VLAN_PORT_MASK       GENMASK(9, 2)
#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK    GENMASK(2, 0)
#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_IDLE    0
#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_READ_ENTRY      1
#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_WRITE_ENTRY     2
#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_CLEAR_TABLE     3

/* MII block 3 registers */
#define VSC73XX_MII_STAT        0x0
#define VSC73XX_MII_CMD         0x1
#define VSC73XX_MII_DATA        0x2

/* Arbiter block 5 registers */
#define VSC73XX_ARBEMPTY                0x0c
#define VSC73XX_ARBDISC                 0x0e
#define VSC73XX_SBACKWDROP              0x12
#define VSC73XX_DBACKWDROP              0x13
#define VSC73XX_ARBBURSTPROB            0x15

/* System block 7 registers */
#define VSC73XX_ICPU_SIPAD              0x01
#define VSC73XX_GMIIDELAY               0x05
#define VSC73XX_ICPU_CTRL               0x10
#define VSC73XX_ICPU_ADDR               0x11
#define VSC73XX_ICPU_SRAM               0x12
#define VSC73XX_HWSEM                   0x13
#define VSC73XX_GLORESET                0x14
#define VSC73XX_ICPU_MBOX_VAL           0x15
#define VSC73XX_ICPU_MBOX_SET           0x16
#define VSC73XX_ICPU_MBOX_CLR           0x17
#define VSC73XX_CHIPID                  0x18
#define VSC73XX_GPIO                    0x34

#define VSC73XX_GMIIDELAY_GMII0_GTXDELAY_NONE   0
#define VSC73XX_GMIIDELAY_GMII0_GTXDELAY_1_4_NS 1
#define VSC73XX_GMIIDELAY_GMII0_GTXDELAY_1_7_NS 2
#define VSC73XX_GMIIDELAY_GMII0_GTXDELAY_2_0_NS 3

#define VSC73XX_GMIIDELAY_GMII0_RXDELAY_NONE    (0 << 4)
#define VSC73XX_GMIIDELAY_GMII0_RXDELAY_1_4_NS  (1 << 4)
#define VSC73XX_GMIIDELAY_GMII0_RXDELAY_1_7_NS  (2 << 4)
#define VSC73XX_GMIIDELAY_GMII0_RXDELAY_2_0_NS  (3 << 4)

#define VSC73XX_ICPU_CTRL_WATCHDOG_RST  BIT(31)
#define VSC73XX_ICPU_CTRL_CLK_DIV_MASK  GENMASK(12, 8)
#define VSC73XX_ICPU_CTRL_SRST_HOLD     BIT(7)
#define VSC73XX_ICPU_CTRL_ICPU_PI_EN    BIT(6)
#define VSC73XX_ICPU_CTRL_BOOT_EN       BIT(3)
#define VSC73XX_ICPU_CTRL_EXT_ACC_EN    BIT(2)
#define VSC73XX_ICPU_CTRL_CLK_EN        BIT(1)
#define VSC73XX_ICPU_CTRL_SRST          BIT(0)

#define VSC73XX_CHIPID_ID_SHIFT         12
#define VSC73XX_CHIPID_ID_MASK          0xffff
#define VSC73XX_CHIPID_REV_SHIFT        28
#define VSC73XX_CHIPID_REV_MASK         0xf
#define VSC73XX_CHIPID_ID_7385          0x7385
#define VSC73XX_CHIPID_ID_7388          0x7388
#define VSC73XX_CHIPID_ID_7395          0x7395
#define VSC73XX_CHIPID_ID_7398          0x7398

#define VSC73XX_GLORESET_STROBE         BIT(4)
#define VSC73XX_GLORESET_ICPU_LOCK      BIT(3)
#define VSC73XX_GLORESET_MEM_LOCK       BIT(2)
#define VSC73XX_GLORESET_PHY_RESET      BIT(1)
#define VSC73XX_GLORESET_MASTER_RESET   BIT(0)

#define VSC7385_CLOCK_DELAY             ((3 << 4) | 3)
#define VSC7385_CLOCK_DELAY_MASK        ((3 << 4) | 3)

#define VSC73XX_ICPU_CTRL_STOP  (VSC73XX_ICPU_CTRL_SRST_HOLD | \
                                 VSC73XX_ICPU_CTRL_BOOT_EN | \
                                 VSC73XX_ICPU_CTRL_EXT_ACC_EN)

#define VSC73XX_ICPU_CTRL_START (VSC73XX_ICPU_CTRL_CLK_DIV | \
                                 VSC73XX_ICPU_CTRL_BOOT_EN | \
                                 VSC73XX_ICPU_CTRL_CLK_EN | \
                                 VSC73XX_ICPU_CTRL_SRST)

#define IS_7385(a) ((a)->chipid == VSC73XX_CHIPID_ID_7385)
#define IS_7388(a) ((a)->chipid == VSC73XX_CHIPID_ID_7388)
#define IS_7395(a) ((a)->chipid == VSC73XX_CHIPID_ID_7395)
#define IS_7398(a) ((a)->chipid == VSC73XX_CHIPID_ID_7398)
#define IS_739X(a) (IS_7395(a) || IS_7398(a))

struct vsc73xx_counter {
        u8 counter;
        const char *name;
};

/* Counters are named according to the MIB standards where applicable.
 * Some counters are custom, non-standard. The standard counters are
 * named in accordance with RFC2819, RFC2021 and IEEE Std 802.3-2002 Annex
 * 30A Counters.
 */
static const struct vsc73xx_counter vsc73xx_rx_counters[] = {
        { 0, "RxEtherStatsPkts" },
        { 1, "RxBroadcast+MulticastPkts" }, /* non-standard counter */
        { 2, "RxTotalErrorPackets" }, /* non-standard counter */
        { 3, "RxEtherStatsBroadcastPkts" },
        { 4, "RxEtherStatsMulticastPkts" },
        { 5, "RxEtherStatsPkts64Octets" },
        { 6, "RxEtherStatsPkts65to127Octets" },
        { 7, "RxEtherStatsPkts128to255Octets" },
        { 8, "RxEtherStatsPkts256to511Octets" },
        { 9, "RxEtherStatsPkts512to1023Octets" },
        { 10, "RxEtherStatsPkts1024to1518Octets" },
        { 11, "RxJumboFrames" }, /* non-standard counter */
        { 12, "RxaPauseMACControlFramesTransmitted" },
        { 13, "RxFIFODrops" }, /* non-standard counter */
        { 14, "RxBackwardDrops" }, /* non-standard counter */
        { 15, "RxClassifierDrops" }, /* non-standard counter */
        { 16, "RxEtherStatsCRCAlignErrors" },
        { 17, "RxEtherStatsUndersizePkts" },
        { 18, "RxEtherStatsOversizePkts" },
        { 19, "RxEtherStatsFragments" },
        { 20, "RxEtherStatsJabbers" },
        { 21, "RxaMACControlFramesReceived" },
        /* 22-24 are undefined */
        { 25, "RxaFramesReceivedOK" },
        { 26, "RxQoSClass0" }, /* non-standard counter */
        { 27, "RxQoSClass1" }, /* non-standard counter */
        { 28, "RxQoSClass2" }, /* non-standard counter */
        { 29, "RxQoSClass3" }, /* non-standard counter */
};

static const struct vsc73xx_counter vsc73xx_tx_counters[] = {
        { 0, "TxEtherStatsPkts" },
        { 1, "TxBroadcast+MulticastPkts" }, /* non-standard counter */
        { 2, "TxTotalErrorPackets" }, /* non-standard counter */
        { 3, "TxEtherStatsBroadcastPkts" },
        { 4, "TxEtherStatsMulticastPkts" },
        { 5, "TxEtherStatsPkts64Octets" },
        { 6, "TxEtherStatsPkts65to127Octets" },
        { 7, "TxEtherStatsPkts128to255Octets" },
        { 8, "TxEtherStatsPkts256to511Octets" },
        { 9, "TxEtherStatsPkts512to1023Octets" },
        { 10, "TxEtherStatsPkts1024to1518Octets" },
        { 11, "TxJumboFrames" }, /* non-standard counter */
        { 12, "TxaPauseMACControlFramesTransmitted" },
        { 13, "TxFIFODrops" }, /* non-standard counter */
        { 14, "TxDrops" }, /* non-standard counter */
        { 15, "TxEtherStatsCollisions" },
        { 16, "TxEtherStatsCRCAlignErrors" },
        { 17, "TxEtherStatsUndersizePkts" },
        { 18, "TxEtherStatsOversizePkts" },
        { 19, "TxEtherStatsFragments" },
        { 20, "TxEtherStatsJabbers" },
        /* 21-24 are undefined */
        { 25, "TxaFramesReceivedOK" },
        { 26, "TxQoSClass0" }, /* non-standard counter */
        { 27, "TxQoSClass1" }, /* non-standard counter */
        { 28, "TxQoSClass2" }, /* non-standard counter */
        { 29, "TxQoSClass3" }, /* non-standard counter */
};

int vsc73xx_is_addr_valid(u8 block, u8 subblock)
{
        switch (block) {
        case VSC73XX_BLOCK_MAC:
                switch (subblock) {
                case 0 ... 4:
                case 6:
                        return 1;
                }
                break;

        case VSC73XX_BLOCK_ANALYZER:
        case VSC73XX_BLOCK_SYSTEM:
                switch (subblock) {
                case 0:
                        return 1;
                }
                break;

        case VSC73XX_BLOCK_MII:
        case VSC73XX_BLOCK_CAPTURE:
        case VSC73XX_BLOCK_ARBITER:
                switch (subblock) {
                case 0 ... 1:
                        return 1;
                }
                break;
        }

        return 0;
}
EXPORT_SYMBOL(vsc73xx_is_addr_valid);

static int vsc73xx_read(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
                        u32 *val)
{
        return vsc->ops->read(vsc, block, subblock, reg, val);
}

static int vsc73xx_write(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
                         u32 val)
{
        return vsc->ops->write(vsc, block, subblock, reg, val);
}

static int vsc73xx_update_bits(struct vsc73xx *vsc, u8 block, u8 subblock,
                               u8 reg, u32 mask, u32 val)
{
        u32 tmp, orig;
        int ret;

        /* Same read-modify-write algorithm as e.g. regmap */
        ret = vsc73xx_read(vsc, block, subblock, reg, &orig);
        if (ret)
                return ret;
        tmp = orig & ~mask;
        tmp |= val & mask;
        return vsc73xx_write(vsc, block, subblock, reg, tmp);
}

static int vsc73xx_detect(struct vsc73xx *vsc)
{
        bool icpu_si_boot_en;
        bool icpu_pi_en;
        u32 val;
        u32 rev;
        int ret;
        u32 id;

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                           VSC73XX_ICPU_MBOX_VAL, &val);
        if (ret) {
                dev_err(vsc->dev, "unable to read mailbox (%d)\n", ret);
                return ret;
        }

        if (val == 0xffffffff) {
                dev_info(vsc->dev, "chip seems dead.\n");
                return -EAGAIN;
        }

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                           VSC73XX_CHIPID, &val);
        if (ret) {
                dev_err(vsc->dev, "unable to read chip id (%d)\n", ret);
                return ret;
        }

        id = (val >> VSC73XX_CHIPID_ID_SHIFT) &
                VSC73XX_CHIPID_ID_MASK;
        switch (id) {
        case VSC73XX_CHIPID_ID_7385:
        case VSC73XX_CHIPID_ID_7388:
        case VSC73XX_CHIPID_ID_7395:
        case VSC73XX_CHIPID_ID_7398:
                break;
        default:
                dev_err(vsc->dev, "unsupported chip, id=%04x\n", id);
                return -ENODEV;
        }

        vsc->chipid = id;
        rev = (val >> VSC73XX_CHIPID_REV_SHIFT) &
                VSC73XX_CHIPID_REV_MASK;
        dev_info(vsc->dev, "VSC%04X (rev: %d) switch found\n", id, rev);

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                           VSC73XX_ICPU_CTRL, &val);
        if (ret) {
                dev_err(vsc->dev, "unable to read iCPU control\n");
                return ret;
        }

        /* The iCPU can always be used but can boot in different ways.
         * If it is initially disabled and has no external memory,
         * we are in control and can do whatever we like, else we
         * are probably in trouble (we need some way to communicate
         * with the running firmware) so we bail out for now.
         */
        icpu_pi_en = !!(val & VSC73XX_ICPU_CTRL_ICPU_PI_EN);
        icpu_si_boot_en = !!(val & VSC73XX_ICPU_CTRL_BOOT_EN);
        if (icpu_si_boot_en && icpu_pi_en) {
                dev_err(vsc->dev,
                        "iCPU enabled boots from SI, has external memory\n");
                dev_err(vsc->dev, "no idea how to deal with this\n");
                return -ENODEV;
        }
        if (icpu_si_boot_en && !icpu_pi_en) {
                dev_err(vsc->dev,
                        "iCPU enabled boots from PI/SI, no external memory\n");
                return -EAGAIN;
        }
        if (!icpu_si_boot_en && icpu_pi_en) {
                dev_err(vsc->dev,
                        "iCPU enabled, boots from PI external memory\n");
                dev_err(vsc->dev, "no idea how to deal with this\n");
                return -ENODEV;
        }
        /* !icpu_si_boot_en && !cpu_pi_en */
        dev_info(vsc->dev, "iCPU disabled, no external memory\n");

        return 0;
}

static int vsc73xx_phy_read(struct dsa_switch *ds, int phy, int regnum)
{
        struct vsc73xx *vsc = ds->priv;
        u32 cmd;
        u32 val;
        int ret;

        /* Setting bit 26 means "read" */
        cmd = BIT(26) | (phy << 21) | (regnum << 16);
        ret = vsc73xx_write(vsc, VSC73XX_BLOCK_MII, 0, 1, cmd);
        if (ret)
                return ret;
        msleep(2);
        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_MII, 0, 2, &val);
        if (ret)
                return ret;
        if (val & BIT(16)) {
                dev_err(vsc->dev, "reading reg %02x from phy%d failed\n",
                        regnum, phy);
                return -EIO;
        }
        val &= 0xFFFFU;

        dev_dbg(vsc->dev, "read reg %02x from phy%d = %04x\n",
                regnum, phy, val);

        return val;
}

static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
                             u16 val)
{
        struct vsc73xx *vsc = ds->priv;
        u32 cmd;
        int ret;

        /* It was found through tedious experiments that this router
         * chip really hates to have it's PHYs reset. They
         * never recover if that happens: autonegotiation stops
         * working after a reset. Just filter out this command.
         * (Resetting the whole chip is OK.)
         */
        if (regnum == 0 && (val & BIT(15))) {
                dev_info(vsc->dev, "reset PHY - disallowed\n");
                return 0;
        }

        cmd = (phy << 21) | (regnum << 16);
        ret = vsc73xx_write(vsc, VSC73XX_BLOCK_MII, 0, 1, cmd);
        if (ret)
                return ret;

        dev_dbg(vsc->dev, "write %04x to reg %02x in phy%d\n",
                val, regnum, phy);
        return 0;
}

static enum dsa_tag_protocol vsc73xx_get_tag_protocol(struct dsa_switch *ds,
                                                      int port,
                                                      enum dsa_tag_protocol mp)
{
        /* The switch internally uses a 8 byte header with length,
         * source port, tag, LPA and priority. This is supposedly
         * only accessible when operating the switch using the internal
         * CPU or with an external CPU mapping the device in, but not
         * when operating the switch over SPI and putting frames in/out
         * on port 6 (the CPU port). So far we must assume that we
         * cannot access the tag. (See "Internal frame header" section
         * 3.9.1 in the manual.)
         */
        return DSA_TAG_PROTO_NONE;
}

static int vsc73xx_setup(struct dsa_switch *ds)
{
        struct vsc73xx *vsc = ds->priv;
        int i;

        dev_info(vsc->dev, "set up the switch\n");

        /* Issue RESET */
        vsc73xx_write(vsc, VSC73XX_BLOCK_SYSTEM, 0, VSC73XX_GLORESET,
                      VSC73XX_GLORESET_MASTER_RESET);
        usleep_range(125, 200);

        /* Initialize memory, initialize RAM bank 0..15 except 6 and 7
         * This sequence appears in the
         * VSC7385 SparX-G5 datasheet section 6.6.1
         * VSC7395 SparX-G5e datasheet section 6.6.1
         * "initialization sequence".
         * No explanation is given to the 0x1010400 magic number.
         */
        for (i = 0; i <= 15; i++) {
                if (i != 6 && i != 7) {
                        vsc73xx_write(vsc, VSC73XX_BLOCK_MEMINIT,
                                      2,
                                      0, 0x1010400 + i);
                        mdelay(1);
                }
        }
        mdelay(30);

        /* Clear MAC table */
        vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0,
                      VSC73XX_MACACCESS,
                      VSC73XX_MACACCESS_CMD_CLEAR_TABLE);

        /* Clear VLAN table */
        vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0,
                      VSC73XX_VLANACCESS,
                      VSC73XX_VLANACCESS_VLAN_TBL_CMD_CLEAR_TABLE);

        msleep(40);

        /* Use 20KiB buffers on all ports on VSC7395
         * The VSC7385 has 16KiB buffers and that is the
         * default if we don't set this up explicitly.
         * Port "31" is "all ports".
         */
        if (IS_739X(vsc))
                vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, 0x1f,
                              VSC73XX_Q_MISC_CONF,
                              VSC73XX_Q_MISC_CONF_EXTENT_MEM);

        /* Put all ports into reset until enabled */
        for (i = 0; i < 7; i++) {
                if (i == 5)
                        continue;
                vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, 4,
                              VSC73XX_MAC_CFG, VSC73XX_MAC_CFG_RESET);
        }

        /* MII delay, set both GTX and RX delay to 2 ns */
        vsc73xx_write(vsc, VSC73XX_BLOCK_SYSTEM, 0, VSC73XX_GMIIDELAY,
                      VSC73XX_GMIIDELAY_GMII0_GTXDELAY_2_0_NS |
                      VSC73XX_GMIIDELAY_GMII0_RXDELAY_2_0_NS);
        /* Enable reception of frames on all ports */
        vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_RECVMASK,
                      0x5f);
        /* IP multicast flood mask (table 144) */
        vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_IFLODMSK,
                      0xff);

        mdelay(50);

        /* Release reset from the internal PHYs */
        vsc73xx_write(vsc, VSC73XX_BLOCK_SYSTEM, 0, VSC73XX_GLORESET,
                      VSC73XX_GLORESET_PHY_RESET);

        udelay(4);

        return 0;
}

static void vsc73xx_init_port(struct vsc73xx *vsc, int port)
{
        u32 val;

        /* MAC configure, first reset the port and then write defaults */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_MAC_CFG,
                      VSC73XX_MAC_CFG_RESET);

        /* Take up the port in 1Gbit mode by default, this will be
         * augmented after auto-negotiation on the PHY-facing
         * ports.
         */
        if (port == CPU_PORT)
                val = VSC73XX_MAC_CFG_1000M_F_RGMII;
        else
                val = VSC73XX_MAC_CFG_1000M_F_PHY;

        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_MAC_CFG,
                      val |
                      VSC73XX_MAC_CFG_TX_EN |
                      VSC73XX_MAC_CFG_RX_EN);

        /* Flow control for the CPU port:
         * Use a zero delay pause frame when pause condition is left
         * Obey pause control frames
         */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_FCCONF,
                      VSC73XX_FCCONF_ZERO_PAUSE_EN |
                      VSC73XX_FCCONF_FLOW_CTRL_OBEY);

        /* Issue pause control frames on PHY facing ports.
         * Allow early initiation of MAC transmission if the amount
         * of egress data is below 512 bytes on CPU port.
         * FIXME: enable 20KiB buffers?
         */
        if (port == CPU_PORT)
                val = VSC73XX_Q_MISC_CONF_EARLY_TX_512;
        else
                val = VSC73XX_Q_MISC_CONF_MAC_PAUSE_MODE;
        val |= VSC73XX_Q_MISC_CONF_EXTENT_MEM;
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_Q_MISC_CONF,
                      val);

        /* Flow control MAC: a MAC address used in flow control frames */
        val = (vsc->addr[5] << 16) | (vsc->addr[4] << 8) | (vsc->addr[3]);
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_FCMACHI,
                      val);
        val = (vsc->addr[2] << 16) | (vsc->addr[1] << 8) | (vsc->addr[0]);
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_FCMACLO,
                      val);

        /* Tell the categorizer to forward pause frames, not control
         * frame. Do not drop anything.
         */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port,
                      VSC73XX_CAT_DROP,
                      VSC73XX_CAT_DROP_FWD_PAUSE_ENA);

        /* Clear all counters */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                      port, VSC73XX_C_RX0, 0);
}

static void vsc73xx_adjust_enable_port(struct vsc73xx *vsc,
                                       int port, struct phy_device *phydev,
                                       u32 initval)
{
        u32 val = initval;
        u8 seed;

        /* Reset this port FIXME: break out subroutine */
        val |= VSC73XX_MAC_CFG_RESET;
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MAC_CFG, val);

        /* Seed the port randomness with randomness */
        get_random_bytes(&seed, 1);
        val |= seed << VSC73XX_MAC_CFG_SEED_OFFSET;
        val |= VSC73XX_MAC_CFG_SEED_LOAD;
        val |= VSC73XX_MAC_CFG_WEXC_DIS;
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MAC_CFG, val);

        /* Flow control for the PHY facing ports:
         * Use a zero delay pause frame when pause condition is left
         * Obey pause control frames
         * When generating pause frames, use 0xff as pause value
         */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_FCCONF,
                      VSC73XX_FCCONF_ZERO_PAUSE_EN |
                      VSC73XX_FCCONF_FLOW_CTRL_OBEY |
                      0xff);

        /* Disallow backward dropping of frames from this port */
        vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ARBITER, 0,
                            VSC73XX_SBACKWDROP, BIT(port), 0);

        /* Enable TX, RX, deassert reset, stop loading seed */
        vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
                            VSC73XX_MAC_CFG,
                            VSC73XX_MAC_CFG_RESET | VSC73XX_MAC_CFG_SEED_LOAD |
                            VSC73XX_MAC_CFG_TX_EN | VSC73XX_MAC_CFG_RX_EN,
                            VSC73XX_MAC_CFG_TX_EN | VSC73XX_MAC_CFG_RX_EN);
}

static void vsc73xx_adjust_link(struct dsa_switch *ds, int port,
                                struct phy_device *phydev)
{
        struct vsc73xx *vsc = ds->priv;
        u32 val;

        /* Special handling of the CPU-facing port */
        if (port == CPU_PORT) {
                /* Other ports are already initialized but not this one */
                vsc73xx_init_port(vsc, CPU_PORT);
                /* Select the external port for this interface (EXT_PORT)
                 * Enable the GMII GTX external clock
                 * Use double data rate (DDR mode)
                 */
                vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
                              CPU_PORT,
                              VSC73XX_ADVPORTM,
                              VSC73XX_ADVPORTM_EXT_PORT |
                              VSC73XX_ADVPORTM_ENA_GTX |
                              VSC73XX_ADVPORTM_DDR_MODE);
        }

        /* This is the MAC confiuration that always need to happen
         * after a PHY or the CPU port comes up or down.
         */
        if (!phydev->link) {
                int maxloop = 10;

                dev_dbg(vsc->dev, "port %d: went down\n",
                        port);

                /* Disable RX on this port */
                vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
                                    VSC73XX_MAC_CFG,
                                    VSC73XX_MAC_CFG_RX_EN, 0);

                /* Discard packets */
                vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ARBITER, 0,
                                    VSC73XX_ARBDISC, BIT(port), BIT(port));

                /* Wait until queue is empty */
                vsc73xx_read(vsc, VSC73XX_BLOCK_ARBITER, 0,
                             VSC73XX_ARBEMPTY, &val);
                while (!(val & BIT(port))) {
                        msleep(1);
                        vsc73xx_read(vsc, VSC73XX_BLOCK_ARBITER, 0,
                                     VSC73XX_ARBEMPTY, &val);
                        if (--maxloop == 0) {
                                dev_err(vsc->dev,
                                        "timeout waiting for block arbiter\n");
                                /* Continue anyway */
                                break;
                        }
                }

                /* Put this port into reset */
                vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MAC_CFG,
                              VSC73XX_MAC_CFG_RESET);

                /* Accept packets again */
                vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ARBITER, 0,
                                    VSC73XX_ARBDISC, BIT(port), 0);

                /* Allow backward dropping of frames from this port */
                vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ARBITER, 0,
                                    VSC73XX_SBACKWDROP, BIT(port), BIT(port));

                /* Receive mask (disable forwarding) */
                vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ANALYZER, 0,
                                    VSC73XX_RECVMASK, BIT(port), 0);

                return;
        }

        /* Figure out what speed was negotiated */
        if (phydev->speed == SPEED_1000) {
                dev_dbg(vsc->dev, "port %d: 1000 Mbit mode full duplex\n",
                        port);

                /* Set up default for internal port or external RGMII */
                if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
                        val = VSC73XX_MAC_CFG_1000M_F_RGMII;
                else
                        val = VSC73XX_MAC_CFG_1000M_F_PHY;
                vsc73xx_adjust_enable_port(vsc, port, phydev, val);
        } else if (phydev->speed == SPEED_100) {
                if (phydev->duplex == DUPLEX_FULL) {
                        val = VSC73XX_MAC_CFG_100_10M_F_PHY;
                        dev_dbg(vsc->dev,
                                "port %d: 100 Mbit full duplex mode\n",
                                port);
                } else {
                        val = VSC73XX_MAC_CFG_100_10M_H_PHY;
                        dev_dbg(vsc->dev,
                                "port %d: 100 Mbit half duplex mode\n",
                                port);
                }
                vsc73xx_adjust_enable_port(vsc, port, phydev, val);
        } else if (phydev->speed == SPEED_10) {
                if (phydev->duplex == DUPLEX_FULL) {
                        val = VSC73XX_MAC_CFG_100_10M_F_PHY;
                        dev_dbg(vsc->dev,
                                "port %d: 10 Mbit full duplex mode\n",
                                port);
                } else {
                        val = VSC73XX_MAC_CFG_100_10M_H_PHY;
                        dev_dbg(vsc->dev,
                                "port %d: 10 Mbit half duplex mode\n",
                                port);
                }
                vsc73xx_adjust_enable_port(vsc, port, phydev, val);
        } else {
                dev_err(vsc->dev,
                        "could not adjust link: unknown speed\n");
        }

        /* Enable port (forwarding) in the receieve mask */
        vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ANALYZER, 0,
                            VSC73XX_RECVMASK, BIT(port), BIT(port));
}

static int vsc73xx_port_enable(struct dsa_switch *ds, int port,
                               struct phy_device *phy)
{
        struct vsc73xx *vsc = ds->priv;

        dev_info(vsc->dev, "enable port %d\n", port);
        vsc73xx_init_port(vsc, port);

        return 0;
}

static void vsc73xx_port_disable(struct dsa_switch *ds, int port)
{
        struct vsc73xx *vsc = ds->priv;

        /* Just put the port into reset */
        vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port,
                      VSC73XX_MAC_CFG, VSC73XX_MAC_CFG_RESET);
}

static const struct vsc73xx_counter *
vsc73xx_find_counter(struct vsc73xx *vsc,
                     u8 counter,
                     bool tx)
{
        const struct vsc73xx_counter *cnts;
        int num_cnts;
        int i;

        if (tx) {
                cnts = vsc73xx_tx_counters;
                num_cnts = ARRAY_SIZE(vsc73xx_tx_counters);
        } else {
                cnts = vsc73xx_rx_counters;
                num_cnts = ARRAY_SIZE(vsc73xx_rx_counters);
        }

        for (i = 0; i < num_cnts; i++) {
                const struct vsc73xx_counter *cnt;

                cnt = &cnts[i];
                if (cnt->counter == counter)
                        return cnt;
        }

        return NULL;
}

static void vsc73xx_get_strings(struct dsa_switch *ds, int port, u32 stringset,
                                uint8_t *data)
{
        const struct vsc73xx_counter *cnt;
        struct vsc73xx *vsc = ds->priv;
        u8 indices[6];
        int i, j;
        u32 val;
        int ret;

        if (stringset != ETH_SS_STATS)
                return;

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port,
                           VSC73XX_C_CFG, &val);
        if (ret)
                return;

        indices[0] = (val & 0x1f); /* RX counter 0 */
        indices[1] = ((val >> 5) & 0x1f); /* RX counter 1 */
        indices[2] = ((val >> 10) & 0x1f); /* RX counter 2 */
        indices[3] = ((val >> 16) & 0x1f); /* TX counter 0 */
        indices[4] = ((val >> 21) & 0x1f); /* TX counter 1 */
        indices[5] = ((val >> 26) & 0x1f); /* TX counter 2 */

        /* The first counters is the RX octets */
        j = 0;
        strncpy(data + j * ETH_GSTRING_LEN,
                "RxEtherStatsOctets", ETH_GSTRING_LEN);
        j++;

        /* Each port supports recording 3 RX counters and 3 TX counters,
         * figure out what counters we use in this set-up and return the
         * names of them. The hardware default counters will be number of
         * packets on RX/TX, combined broadcast+multicast packets RX/TX and
         * total error packets RX/TX.
         */
        for (i = 0; i < 3; i++) {
                cnt = vsc73xx_find_counter(vsc, indices[i], false);
                if (cnt)
                        strncpy(data + j * ETH_GSTRING_LEN,
                                cnt->name, ETH_GSTRING_LEN);
                j++;
        }

        /* TX stats begins with the number of TX octets */
        strncpy(data + j * ETH_GSTRING_LEN,
                "TxEtherStatsOctets", ETH_GSTRING_LEN);
        j++;

        for (i = 3; i < 6; i++) {
                cnt = vsc73xx_find_counter(vsc, indices[i], true);
                if (cnt)
                        strncpy(data + j * ETH_GSTRING_LEN,
                                cnt->name, ETH_GSTRING_LEN);
                j++;
        }
}

static int vsc73xx_get_sset_count(struct dsa_switch *ds, int port, int sset)
{
        /* We only support SS_STATS */
        if (sset != ETH_SS_STATS)
                return 0;
        /* RX and TX packets, then 3 RX counters, 3 TX counters */
        return 8;
}

static void vsc73xx_get_ethtool_stats(struct dsa_switch *ds, int port,
                                      uint64_t *data)
{
        struct vsc73xx *vsc = ds->priv;
        u8 regs[] = {
                VSC73XX_RXOCT,
                VSC73XX_C_RX0,
                VSC73XX_C_RX1,
                VSC73XX_C_RX2,
                VSC73XX_TXOCT,
                VSC73XX_C_TX0,
                VSC73XX_C_TX1,
                VSC73XX_C_TX2,
        };
        u32 val;
        int ret;
        int i;

        for (i = 0; i < ARRAY_SIZE(regs); i++) {
                ret = vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port,
                                   regs[i], &val);
                if (ret) {
                        dev_err(vsc->dev, "error reading counter %d\n", i);
                        return;
                }
                data[i] = val;
        }
}

static int vsc73xx_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
{
        struct vsc73xx *vsc = ds->priv;

        return vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port,
                             VSC73XX_MAXLEN, new_mtu);
}

/* According to application not "VSC7398 Jumbo Frames" setting
 * up the MTU to 9.6 KB does not affect the performance on standard
 * frames. It is clear from the application note that
 * "9.6 kilobytes" == 9600 bytes.
 */
static int vsc73xx_get_max_mtu(struct dsa_switch *ds, int port)
{
        return 9600;
}

static const struct dsa_switch_ops vsc73xx_ds_ops = {
        .get_tag_protocol = vsc73xx_get_tag_protocol,
        .setup = vsc73xx_setup,
        .phy_read = vsc73xx_phy_read,
        .phy_write = vsc73xx_phy_write,
        .adjust_link = vsc73xx_adjust_link,
        .get_strings = vsc73xx_get_strings,
        .get_ethtool_stats = vsc73xx_get_ethtool_stats,
        .get_sset_count = vsc73xx_get_sset_count,
        .port_enable = vsc73xx_port_enable,
        .port_disable = vsc73xx_port_disable,
        .port_change_mtu = vsc73xx_change_mtu,
        .port_max_mtu = vsc73xx_get_max_mtu,
};

static int vsc73xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
        struct vsc73xx *vsc = gpiochip_get_data(chip);
        u32 val;
        int ret;

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                           VSC73XX_GPIO, &val);
        if (ret)
                return ret;

        return !!(val & BIT(offset));
}

static void vsc73xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
                             int val)
{
        struct vsc73xx *vsc = gpiochip_get_data(chip);
        u32 tmp = val ? BIT(offset) : 0;

        vsc73xx_update_bits(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                            VSC73XX_GPIO, BIT(offset), tmp);
}

static int vsc73xx_gpio_direction_output(struct gpio_chip *chip,
                                         unsigned int offset, int val)
{
        struct vsc73xx *vsc = gpiochip_get_data(chip);
        u32 tmp = val ? BIT(offset) : 0;

        return vsc73xx_update_bits(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                                   VSC73XX_GPIO, BIT(offset + 4) | BIT(offset),
                                   BIT(offset + 4) | tmp);
}

static int vsc73xx_gpio_direction_input(struct gpio_chip *chip,
                                        unsigned int offset)
{
        struct vsc73xx *vsc = gpiochip_get_data(chip);

        return  vsc73xx_update_bits(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                                    VSC73XX_GPIO, BIT(offset + 4),
                                    0);
}

static int vsc73xx_gpio_get_direction(struct gpio_chip *chip,
                                      unsigned int offset)
{
        struct vsc73xx *vsc = gpiochip_get_data(chip);
        u32 val;
        int ret;

        ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0,
                           VSC73XX_GPIO, &val);
        if (ret)
                return ret;

        return !(val & BIT(offset + 4));
}

static int vsc73xx_gpio_probe(struct vsc73xx *vsc)
{
        int ret;

        vsc->gc.label = devm_kasprintf(vsc->dev, GFP_KERNEL, "VSC%04x",
                                       vsc->chipid);
        vsc->gc.ngpio = 4;
        vsc->gc.owner = THIS_MODULE;
        vsc->gc.parent = vsc->dev;
#if IS_ENABLED(CONFIG_OF_GPIO)
        vsc->gc.of_node = vsc->dev->of_node;
#endif
        vsc->gc.base = -1;
        vsc->gc.get = vsc73xx_gpio_get;
        vsc->gc.set = vsc73xx_gpio_set;
        vsc->gc.direction_input = vsc73xx_gpio_direction_input;
        vsc->gc.direction_output = vsc73xx_gpio_direction_output;
        vsc->gc.get_direction = vsc73xx_gpio_get_direction;
        vsc->gc.can_sleep = true;
        ret = devm_gpiochip_add_data(vsc->dev, &vsc->gc, vsc);
        if (ret) {
                dev_err(vsc->dev, "unable to register GPIO chip\n");
                return ret;
        }
        return 0;
}

int vsc73xx_probe(struct vsc73xx *vsc)
{
        struct device *dev = vsc->dev;
        int ret;

        /* Release reset, if any */
        vsc->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(vsc->reset)) {
                dev_err(dev, "failed to get RESET GPIO\n");
                return PTR_ERR(vsc->reset);
        }
        if (vsc->reset)
                /* Wait 20ms according to datasheet table 245 */
                msleep(20);

        ret = vsc73xx_detect(vsc);
        if (ret == -EAGAIN) {
                dev_err(vsc->dev,
                        "Chip seems to be out of control. Assert reset and try again.\n");
                gpiod_set_value_cansleep(vsc->reset, 1);
                /* Reset pulse should be 20ns minimum, according to datasheet
                 * table 245, so 10us should be fine
                 */
                usleep_range(10, 100);
                gpiod_set_value_cansleep(vsc->reset, 0);
                /* Wait 20ms according to datasheet table 245 */
                msleep(20);
                ret = vsc73xx_detect(vsc);
        }
        if (ret) {
                dev_err(dev, "no chip found (%d)\n", ret);
                return -ENODEV;
        }

        eth_random_addr(vsc->addr);
        dev_info(vsc->dev,
                 "MAC for control frames: %02X:%02X:%02X:%02X:%02X:%02X\n",
                 vsc->addr[0], vsc->addr[1], vsc->addr[2],
                 vsc->addr[3], vsc->addr[4], vsc->addr[5]);

        /* The VSC7395 switch chips have 5+1 ports which means 5
         * ordinary ports and a sixth CPU port facing the processor
         * with an RGMII interface. These ports are numbered 0..4
         * and 6, so they leave a "hole" in the port map for port 5,
         * which is invalid.
         *
         * The VSC7398 has 8 ports, port 7 is again the CPU port.
         *
         * We allocate 8 ports and avoid access to the nonexistant
         * ports.
         */
        vsc->ds = devm_kzalloc(dev, sizeof(*vsc->ds), GFP_KERNEL);
        if (!vsc->ds)
                return -ENOMEM;

        vsc->ds->dev = dev;
        vsc->ds->num_ports = 8;
        vsc->ds->priv = vsc;

        vsc->ds->ops = &vsc73xx_ds_ops;
        ret = dsa_register_switch(vsc->ds);
        if (ret) {
                dev_err(dev, "unable to register switch (%d)\n", ret);
                return ret;
        }

        ret = vsc73xx_gpio_probe(vsc);
        if (ret) {
                dsa_unregister_switch(vsc->ds);
                return ret;
        }

        return 0;
}
EXPORT_SYMBOL(vsc73xx_probe);

int vsc73xx_remove(struct vsc73xx *vsc)
{
        dsa_unregister_switch(vsc->ds);
        gpiod_set_value(vsc->reset, 1);

        return 0;
}
EXPORT_SYMBOL(vsc73xx_remove);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("Vitesse VSC7385/7388/7395/7398 driver");
MODULE_LICENSE("GPL v2");