Avoid beyond bounds copy while caching ACL

[zen-stable.git] / drivers / spi / spi-fsl-spi.c

/*
 * Freescale SPI controller driver.
 *
 * Maintainer: Kumar Gala
 *
 * Copyright (C) 2006 Polycom, Inc.
 * Copyright 2010 Freescale Semiconductor, Inc.
 *
 * CPM SPI and QE buffer descriptors mode support:
 * Copyright (c) 2009  MontaVista Software, Inc.
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/platform_device.h>
#include <linux/fsl_devices.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>

#include <sysdev/fsl_soc.h>
#include <asm/cpm.h>
#include <asm/qe.h>

#include "spi-fsl-lib.h"

/* CPM1 and CPM2 are mutually exclusive. */
#ifdef CONFIG_CPM1
#include <asm/cpm1.h>
#define CPM_SPI_CMD mk_cr_cmd(CPM_CR_CH_SPI, 0)
#else
#include <asm/cpm2.h>
#define CPM_SPI_CMD mk_cr_cmd(CPM_CR_SPI_PAGE, CPM_CR_SPI_SBLOCK, 0, 0)
#endif

/* SPI Controller registers */
struct fsl_spi_reg {
        u8 res1[0x20];
        __be32 mode;
        __be32 event;
        __be32 mask;
        __be32 command;
        __be32 transmit;
        __be32 receive;
};

/* SPI Controller mode register definitions */
#define SPMODE_LOOP             (1 << 30)
#define SPMODE_CI_INACTIVEHIGH  (1 << 29)
#define SPMODE_CP_BEGIN_EDGECLK (1 << 28)
#define SPMODE_DIV16            (1 << 27)
#define SPMODE_REV              (1 << 26)
#define SPMODE_MS               (1 << 25)
#define SPMODE_ENABLE           (1 << 24)
#define SPMODE_LEN(x)           ((x) << 20)
#define SPMODE_PM(x)            ((x) << 16)
#define SPMODE_OP               (1 << 14)
#define SPMODE_CG(x)            ((x) << 7)

/*
 * Default for SPI Mode:
 *      SPI MODE 0 (inactive low, phase middle, MSB, 8-bit length, slow clk
 */
#define SPMODE_INIT_VAL (SPMODE_CI_INACTIVEHIGH | SPMODE_DIV16 | SPMODE_REV | \
                         SPMODE_MS | SPMODE_LEN(7) | SPMODE_PM(0xf))

/* SPIE register values */
#define SPIE_NE         0x00000200      /* Not empty */
#define SPIE_NF         0x00000100      /* Not full */

/* SPIM register values */
#define SPIM_NE         0x00000200      /* Not empty */
#define SPIM_NF         0x00000100      /* Not full */

#define SPIE_TXB        0x00000200      /* Last char is written to tx fifo */
#define SPIE_RXB        0x00000100      /* Last char is written to rx buf */

/* SPCOM register values */
#define SPCOM_STR       (1 << 23)       /* Start transmit */

#define SPI_PRAM_SIZE   0x100
#define SPI_MRBLR       ((unsigned int)PAGE_SIZE)

static void *fsl_dummy_rx;
static DEFINE_MUTEX(fsl_dummy_rx_lock);
static int fsl_dummy_rx_refcnt;

static void fsl_spi_change_mode(struct spi_device *spi)
{
        struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
        struct spi_mpc8xxx_cs *cs = spi->controller_state;
        struct fsl_spi_reg *reg_base = mspi->reg_base;
        __be32 __iomem *mode = &reg_base->mode;
        unsigned long flags;

        if (cs->hw_mode == mpc8xxx_spi_read_reg(mode))
                return;

        /* Turn off IRQs locally to minimize time that SPI is disabled. */
        local_irq_save(flags);

        /* Turn off SPI unit prior changing mode */
        mpc8xxx_spi_write_reg(mode, cs->hw_mode & ~SPMODE_ENABLE);

        /* When in CPM mode, we need to reinit tx and rx. */
        if (mspi->flags & SPI_CPM_MODE) {
                if (mspi->flags & SPI_QE) {
                        qe_issue_cmd(QE_INIT_TX_RX, mspi->subblock,
                                     QE_CR_PROTOCOL_UNSPECIFIED, 0);
                } else {
                        cpm_command(CPM_SPI_CMD, CPM_CR_INIT_TRX);
                        if (mspi->flags & SPI_CPM1) {
                                out_be16(&mspi->pram->rbptr,
                                         in_be16(&mspi->pram->rbase));
                                out_be16(&mspi->pram->tbptr,
                                         in_be16(&mspi->pram->tbase));
                        }
                }
        }
        mpc8xxx_spi_write_reg(mode, cs->hw_mode);
        local_irq_restore(flags);
}

static void fsl_spi_chipselect(struct spi_device *spi, int value)
{
        struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
        struct fsl_spi_platform_data *pdata = spi->dev.parent->platform_data;
        bool pol = spi->mode & SPI_CS_HIGH;
        struct spi_mpc8xxx_cs   *cs = spi->controller_state;

        if (value == BITBANG_CS_INACTIVE) {
                if (pdata->cs_control)
                        pdata->cs_control(spi, !pol);
        }

        if (value == BITBANG_CS_ACTIVE) {
                mpc8xxx_spi->rx_shift = cs->rx_shift;
                mpc8xxx_spi->tx_shift = cs->tx_shift;
                mpc8xxx_spi->get_rx = cs->get_rx;
                mpc8xxx_spi->get_tx = cs->get_tx;

                fsl_spi_change_mode(spi);

                if (pdata->cs_control)
                        pdata->cs_control(spi, pol);
        }
}

static int mspi_apply_cpu_mode_quirks(struct spi_mpc8xxx_cs *cs,
                                struct spi_device *spi,
                                struct mpc8xxx_spi *mpc8xxx_spi,
                                int bits_per_word)
{
        cs->rx_shift = 0;
        cs->tx_shift = 0;
        if (bits_per_word <= 8) {
                cs->get_rx = mpc8xxx_spi_rx_buf_u8;
                cs->get_tx = mpc8xxx_spi_tx_buf_u8;
                if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
                        cs->rx_shift = 16;
                        cs->tx_shift = 24;
                }
        } else if (bits_per_word <= 16) {
                cs->get_rx = mpc8xxx_spi_rx_buf_u16;
                cs->get_tx = mpc8xxx_spi_tx_buf_u16;
                if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
                        cs->rx_shift = 16;
                        cs->tx_shift = 16;
                }
        } else if (bits_per_word <= 32) {
                cs->get_rx = mpc8xxx_spi_rx_buf_u32;
                cs->get_tx = mpc8xxx_spi_tx_buf_u32;
        } else
                return -EINVAL;

        if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE &&
            spi->mode & SPI_LSB_FIRST) {
                cs->tx_shift = 0;
                if (bits_per_word <= 8)
                        cs->rx_shift = 8;
                else
                        cs->rx_shift = 0;
        }
        mpc8xxx_spi->rx_shift = cs->rx_shift;
        mpc8xxx_spi->tx_shift = cs->tx_shift;
        mpc8xxx_spi->get_rx = cs->get_rx;
        mpc8xxx_spi->get_tx = cs->get_tx;

        return bits_per_word;
}

static int mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,
                                struct spi_device *spi,
                                int bits_per_word)
{
        /* QE uses Little Endian for words > 8
         * so transform all words > 8 into 8 bits
         * Unfortnatly that doesn't work for LSB so
         * reject these for now */
        /* Note: 32 bits word, LSB works iff
         * tfcr/rfcr is set to CPMFCR_GBL */
        if (spi->mode & SPI_LSB_FIRST &&
            bits_per_word > 8)
                return -EINVAL;
        if (bits_per_word > 8)
                return 8; /* pretend its 8 bits */
        return bits_per_word;
}

static int fsl_spi_setup_transfer(struct spi_device *spi,
                                        struct spi_transfer *t)
{
        struct mpc8xxx_spi *mpc8xxx_spi;
        int bits_per_word = 0;
        u8 pm;
        u32 hz = 0;
        struct spi_mpc8xxx_cs   *cs = spi->controller_state;

        mpc8xxx_spi = spi_master_get_devdata(spi->master);

        if (t) {
                bits_per_word = t->bits_per_word;
                hz = t->speed_hz;
        }

        /* spi_transfer level calls that work per-word */
        if (!bits_per_word)
                bits_per_word = spi->bits_per_word;

        /* Make sure its a bit width we support [4..16, 32] */
        if ((bits_per_word < 4)
            || ((bits_per_word > 16) && (bits_per_word != 32)))
                return -EINVAL;

        if (!hz)
                hz = spi->max_speed_hz;

        if (!(mpc8xxx_spi->flags & SPI_CPM_MODE))
                bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,
                                                           mpc8xxx_spi,
                                                           bits_per_word);
        else if (mpc8xxx_spi->flags & SPI_QE)
                bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,
                                                          bits_per_word);

        if (bits_per_word < 0)
                return bits_per_word;

        if (bits_per_word == 32)
                bits_per_word = 0;
        else
                bits_per_word = bits_per_word - 1;

        /* mask out bits we are going to set */
        cs->hw_mode &= ~(SPMODE_LEN(0xF) | SPMODE_DIV16
                                  | SPMODE_PM(0xF));

        cs->hw_mode |= SPMODE_LEN(bits_per_word);

        if ((mpc8xxx_spi->spibrg / hz) > 64) {
                cs->hw_mode |= SPMODE_DIV16;
                pm = (mpc8xxx_spi->spibrg - 1) / (hz * 64) + 1;

                WARN_ONCE(pm > 16, "%s: Requested speed is too low: %d Hz. "
                          "Will use %d Hz instead.\n", dev_name(&spi->dev),
                          hz, mpc8xxx_spi->spibrg / 1024);
                if (pm > 16)
                        pm = 16;
        } else {
                pm = (mpc8xxx_spi->spibrg - 1) / (hz * 4) + 1;
        }
        if (pm)
                pm--;

        cs->hw_mode |= SPMODE_PM(pm);

        fsl_spi_change_mode(spi);
        return 0;
}

static void fsl_spi_cpm_bufs_start(struct mpc8xxx_spi *mspi)
{
        struct cpm_buf_desc __iomem *tx_bd = mspi->tx_bd;
        struct cpm_buf_desc __iomem *rx_bd = mspi->rx_bd;
        unsigned int xfer_len = min(mspi->count, SPI_MRBLR);
        unsigned int xfer_ofs;
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        xfer_ofs = mspi->xfer_in_progress->len - mspi->count;

        if (mspi->rx_dma == mspi->dma_dummy_rx)
                out_be32(&rx_bd->cbd_bufaddr, mspi->rx_dma);
        else
                out_be32(&rx_bd->cbd_bufaddr, mspi->rx_dma + xfer_ofs);
        out_be16(&rx_bd->cbd_datlen, 0);
        out_be16(&rx_bd->cbd_sc, BD_SC_EMPTY | BD_SC_INTRPT | BD_SC_WRAP);

        if (mspi->tx_dma == mspi->dma_dummy_tx)
                out_be32(&tx_bd->cbd_bufaddr, mspi->tx_dma);
        else
                out_be32(&tx_bd->cbd_bufaddr, mspi->tx_dma + xfer_ofs);
        out_be16(&tx_bd->cbd_datlen, xfer_len);
        out_be16(&tx_bd->cbd_sc, BD_SC_READY | BD_SC_INTRPT | BD_SC_WRAP |
                                 BD_SC_LAST);

        /* start transfer */
        mpc8xxx_spi_write_reg(&reg_base->command, SPCOM_STR);
}

static int fsl_spi_cpm_bufs(struct mpc8xxx_spi *mspi,
                                struct spi_transfer *t, bool is_dma_mapped)
{
        struct device *dev = mspi->dev;
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        if (is_dma_mapped) {
                mspi->map_tx_dma = 0;
                mspi->map_rx_dma = 0;
        } else {
                mspi->map_tx_dma = 1;
                mspi->map_rx_dma = 1;
        }

        if (!t->tx_buf) {
                mspi->tx_dma = mspi->dma_dummy_tx;
                mspi->map_tx_dma = 0;
        }

        if (!t->rx_buf) {
                mspi->rx_dma = mspi->dma_dummy_rx;
                mspi->map_rx_dma = 0;
        }

        if (mspi->map_tx_dma) {
                void *nonconst_tx = (void *)mspi->tx; /* shut up gcc */

                mspi->tx_dma = dma_map_single(dev, nonconst_tx, t->len,
                                              DMA_TO_DEVICE);
                if (dma_mapping_error(dev, mspi->tx_dma)) {
                        dev_err(dev, "unable to map tx dma\n");
                        return -ENOMEM;
                }
        } else if (t->tx_buf) {
                mspi->tx_dma = t->tx_dma;
        }

        if (mspi->map_rx_dma) {
                mspi->rx_dma = dma_map_single(dev, mspi->rx, t->len,
                                              DMA_FROM_DEVICE);
                if (dma_mapping_error(dev, mspi->rx_dma)) {
                        dev_err(dev, "unable to map rx dma\n");
                        goto err_rx_dma;
                }
        } else if (t->rx_buf) {
                mspi->rx_dma = t->rx_dma;
        }

        /* enable rx ints */
        mpc8xxx_spi_write_reg(&reg_base->mask, SPIE_RXB);

        mspi->xfer_in_progress = t;
        mspi->count = t->len;

        /* start CPM transfers */
        fsl_spi_cpm_bufs_start(mspi);

        return 0;

err_rx_dma:
        if (mspi->map_tx_dma)
                dma_unmap_single(dev, mspi->tx_dma, t->len, DMA_TO_DEVICE);
        return -ENOMEM;
}

static void fsl_spi_cpm_bufs_complete(struct mpc8xxx_spi *mspi)
{
        struct device *dev = mspi->dev;
        struct spi_transfer *t = mspi->xfer_in_progress;

        if (mspi->map_tx_dma)
                dma_unmap_single(dev, mspi->tx_dma, t->len, DMA_TO_DEVICE);
        if (mspi->map_rx_dma)
                dma_unmap_single(dev, mspi->rx_dma, t->len, DMA_FROM_DEVICE);
        mspi->xfer_in_progress = NULL;
}

static int fsl_spi_cpu_bufs(struct mpc8xxx_spi *mspi,
                                struct spi_transfer *t, unsigned int len)
{
        u32 word;
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        mspi->count = len;

        /* enable rx ints */
        mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);

        /* transmit word */
        word = mspi->get_tx(mspi);
        mpc8xxx_spi_write_reg(&reg_base->transmit, word);

        return 0;
}

static int fsl_spi_bufs(struct spi_device *spi, struct spi_transfer *t,
                            bool is_dma_mapped)
{
        struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
        struct fsl_spi_reg *reg_base;
        unsigned int len = t->len;
        u8 bits_per_word;
        int ret;

        reg_base = mpc8xxx_spi->reg_base;
        bits_per_word = spi->bits_per_word;
        if (t->bits_per_word)
                bits_per_word = t->bits_per_word;

        if (bits_per_word > 8) {
                /* invalid length? */
                if (len & 1)
                        return -EINVAL;
                len /= 2;
        }
        if (bits_per_word > 16) {
                /* invalid length? */
                if (len & 1)
                        return -EINVAL;
                len /= 2;
        }

        mpc8xxx_spi->tx = t->tx_buf;
        mpc8xxx_spi->rx = t->rx_buf;

        INIT_COMPLETION(mpc8xxx_spi->done);

        if (mpc8xxx_spi->flags & SPI_CPM_MODE)
                ret = fsl_spi_cpm_bufs(mpc8xxx_spi, t, is_dma_mapped);
        else
                ret = fsl_spi_cpu_bufs(mpc8xxx_spi, t, len);
        if (ret)
                return ret;

        wait_for_completion(&mpc8xxx_spi->done);

        /* disable rx ints */
        mpc8xxx_spi_write_reg(&reg_base->mask, 0);

        if (mpc8xxx_spi->flags & SPI_CPM_MODE)
                fsl_spi_cpm_bufs_complete(mpc8xxx_spi);

        return mpc8xxx_spi->count;
}

static void fsl_spi_do_one_msg(struct spi_message *m)
{
        struct spi_device *spi = m->spi;
        struct spi_transfer *t;
        unsigned int cs_change;
        const int nsecs = 50;
        int status;

        cs_change = 1;
        status = 0;
        list_for_each_entry(t, &m->transfers, transfer_list) {
                if (t->bits_per_word || t->speed_hz) {
                        /* Don't allow changes if CS is active */
                        status = -EINVAL;

                        if (cs_change)
                                status = fsl_spi_setup_transfer(spi, t);
                        if (status < 0)
                                break;
                }

                if (cs_change) {
                        fsl_spi_chipselect(spi, BITBANG_CS_ACTIVE);
                        ndelay(nsecs);
                }
                cs_change = t->cs_change;
                if (t->len)
                        status = fsl_spi_bufs(spi, t, m->is_dma_mapped);
                if (status) {
                        status = -EMSGSIZE;
                        break;
                }
                m->actual_length += t->len;

                if (t->delay_usecs)
                        udelay(t->delay_usecs);

                if (cs_change) {
                        ndelay(nsecs);
                        fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
                        ndelay(nsecs);
                }
        }

        m->status = status;
        m->complete(m->context);

        if (status || !cs_change) {
                ndelay(nsecs);
                fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
        }

        fsl_spi_setup_transfer(spi, NULL);
}

static int fsl_spi_setup(struct spi_device *spi)
{
        struct mpc8xxx_spi *mpc8xxx_spi;
        struct fsl_spi_reg *reg_base;
        int retval;
        u32 hw_mode;
        struct spi_mpc8xxx_cs   *cs = spi->controller_state;

        if (!spi->max_speed_hz)
                return -EINVAL;

        if (!cs) {
                cs = kzalloc(sizeof *cs, GFP_KERNEL);
                if (!cs)
                        return -ENOMEM;
                spi->controller_state = cs;
        }
        mpc8xxx_spi = spi_master_get_devdata(spi->master);

        reg_base = mpc8xxx_spi->reg_base;

        hw_mode = cs->hw_mode; /* Save original settings */
        cs->hw_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
        /* mask out bits we are going to set */
        cs->hw_mode &= ~(SPMODE_CP_BEGIN_EDGECLK | SPMODE_CI_INACTIVEHIGH
                         | SPMODE_REV | SPMODE_LOOP);

        if (spi->mode & SPI_CPHA)
                cs->hw_mode |= SPMODE_CP_BEGIN_EDGECLK;
        if (spi->mode & SPI_CPOL)
                cs->hw_mode |= SPMODE_CI_INACTIVEHIGH;
        if (!(spi->mode & SPI_LSB_FIRST))
                cs->hw_mode |= SPMODE_REV;
        if (spi->mode & SPI_LOOP)
                cs->hw_mode |= SPMODE_LOOP;

        retval = fsl_spi_setup_transfer(spi, NULL);
        if (retval < 0) {
                cs->hw_mode = hw_mode; /* Restore settings */
                return retval;
        }
        return 0;
}

static void fsl_spi_cpm_irq(struct mpc8xxx_spi *mspi, u32 events)
{
        u16 len;
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        dev_dbg(mspi->dev, "%s: bd datlen %d, count %d\n", __func__,
                in_be16(&mspi->rx_bd->cbd_datlen), mspi->count);

        len = in_be16(&mspi->rx_bd->cbd_datlen);
        if (len > mspi->count) {
                WARN_ON(1);
                len = mspi->count;
        }

        /* Clear the events */
        mpc8xxx_spi_write_reg(&reg_base->event, events);

        mspi->count -= len;
        if (mspi->count)
                fsl_spi_cpm_bufs_start(mspi);
        else
                complete(&mspi->done);
}

static void fsl_spi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
{
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        /* We need handle RX first */
        if (events & SPIE_NE) {
                u32 rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);

                if (mspi->rx)
                        mspi->get_rx(rx_data, mspi);
        }

        if ((events & SPIE_NF) == 0)
                /* spin until TX is done */
                while (((events =
                        mpc8xxx_spi_read_reg(&reg_base->event)) &
                                                SPIE_NF) == 0)
                        cpu_relax();

        /* Clear the events */
        mpc8xxx_spi_write_reg(&reg_base->event, events);

        mspi->count -= 1;
        if (mspi->count) {
                u32 word = mspi->get_tx(mspi);

                mpc8xxx_spi_write_reg(&reg_base->transmit, word);
        } else {
                complete(&mspi->done);
        }
}

static irqreturn_t fsl_spi_irq(s32 irq, void *context_data)
{
        struct mpc8xxx_spi *mspi = context_data;
        irqreturn_t ret = IRQ_NONE;
        u32 events;
        struct fsl_spi_reg *reg_base = mspi->reg_base;

        /* Get interrupt events(tx/rx) */
        events = mpc8xxx_spi_read_reg(&reg_base->event);
        if (events)
                ret = IRQ_HANDLED;

        dev_dbg(mspi->dev, "%s: events %x\n", __func__, events);

        if (mspi->flags & SPI_CPM_MODE)
                fsl_spi_cpm_irq(mspi, events);
        else
                fsl_spi_cpu_irq(mspi, events);

        return ret;
}

static void *fsl_spi_alloc_dummy_rx(void)
{
        mutex_lock(&fsl_dummy_rx_lock);

        if (!fsl_dummy_rx)
                fsl_dummy_rx = kmalloc(SPI_MRBLR, GFP_KERNEL);
        if (fsl_dummy_rx)
                fsl_dummy_rx_refcnt++;

        mutex_unlock(&fsl_dummy_rx_lock);

        return fsl_dummy_rx;
}

static void fsl_spi_free_dummy_rx(void)
{
        mutex_lock(&fsl_dummy_rx_lock);

        switch (fsl_dummy_rx_refcnt) {
        case 0:
                WARN_ON(1);
                break;
        case 1:
                kfree(fsl_dummy_rx);
                fsl_dummy_rx = NULL;
                /* fall through */
        default:
                fsl_dummy_rx_refcnt--;
                break;
        }

        mutex_unlock(&fsl_dummy_rx_lock);
}

static unsigned long fsl_spi_cpm_get_pram(struct mpc8xxx_spi *mspi)
{
        struct device *dev = mspi->dev;
        struct device_node *np = dev->of_node;
        const u32 *iprop;
        int size;
        void __iomem *spi_base;
        unsigned long pram_ofs = -ENOMEM;

        /* Can't use of_address_to_resource(), QE muram isn't at 0. */
        iprop = of_get_property(np, "reg", &size);

        /* QE with a fixed pram location? */
        if (mspi->flags & SPI_QE && iprop && size == sizeof(*iprop) * 4)
                return cpm_muram_alloc_fixed(iprop[2], SPI_PRAM_SIZE);

        /* QE but with a dynamic pram location? */
        if (mspi->flags & SPI_QE) {
                pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
                qe_issue_cmd(QE_ASSIGN_PAGE_TO_DEVICE, mspi->subblock,
                                QE_CR_PROTOCOL_UNSPECIFIED, pram_ofs);
                return pram_ofs;
        }

        spi_base = of_iomap(np, 1);
        if (spi_base == NULL)
                return -EINVAL;

        if (mspi->flags & SPI_CPM2) {
                pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
                out_be16(spi_base, pram_ofs);
        } else {
                struct spi_pram __iomem *pram = spi_base;
                u16 rpbase = in_be16(&pram->rpbase);

                /* Microcode relocation patch applied? */
                if (rpbase)
                        pram_ofs = rpbase;
                else {
                        pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
                        out_be16(spi_base, pram_ofs);
                }
        }

        iounmap(spi_base);
        return pram_ofs;
}

static int fsl_spi_cpm_init(struct mpc8xxx_spi *mspi)
{
        struct device *dev = mspi->dev;
        struct device_node *np = dev->of_node;
        const u32 *iprop;
        int size;
        unsigned long pram_ofs;
        unsigned long bds_ofs;

        if (!(mspi->flags & SPI_CPM_MODE))
                return 0;

        if (!fsl_spi_alloc_dummy_rx())
                return -ENOMEM;

        if (mspi->flags & SPI_QE) {
                iprop = of_get_property(np, "cell-index", &size);
                if (iprop && size == sizeof(*iprop))
                        mspi->subblock = *iprop;

                switch (mspi->subblock) {
                default:
                        dev_warn(dev, "cell-index unspecified, assuming SPI1");
                        /* fall through */
                case 0:
                        mspi->subblock = QE_CR_SUBBLOCK_SPI1;
                        break;
                case 1:
                        mspi->subblock = QE_CR_SUBBLOCK_SPI2;
                        break;
                }
        }

        pram_ofs = fsl_spi_cpm_get_pram(mspi);
        if (IS_ERR_VALUE(pram_ofs)) {
                dev_err(dev, "can't allocate spi parameter ram\n");
                goto err_pram;
        }

        bds_ofs = cpm_muram_alloc(sizeof(*mspi->tx_bd) +
                                  sizeof(*mspi->rx_bd), 8);
        if (IS_ERR_VALUE(bds_ofs)) {
                dev_err(dev, "can't allocate bds\n");
                goto err_bds;
        }

        mspi->dma_dummy_tx = dma_map_single(dev, empty_zero_page, PAGE_SIZE,
                                            DMA_TO_DEVICE);
        if (dma_mapping_error(dev, mspi->dma_dummy_tx)) {
                dev_err(dev, "unable to map dummy tx buffer\n");
                goto err_dummy_tx;
        }

        mspi->dma_dummy_rx = dma_map_single(dev, fsl_dummy_rx, SPI_MRBLR,
                                            DMA_FROM_DEVICE);
        if (dma_mapping_error(dev, mspi->dma_dummy_rx)) {
                dev_err(dev, "unable to map dummy rx buffer\n");
                goto err_dummy_rx;
        }

        mspi->pram = cpm_muram_addr(pram_ofs);

        mspi->tx_bd = cpm_muram_addr(bds_ofs);
        mspi->rx_bd = cpm_muram_addr(bds_ofs + sizeof(*mspi->tx_bd));

        /* Initialize parameter ram. */
        out_be16(&mspi->pram->tbase, cpm_muram_offset(mspi->tx_bd));
        out_be16(&mspi->pram->rbase, cpm_muram_offset(mspi->rx_bd));
        out_8(&mspi->pram->tfcr, CPMFCR_EB | CPMFCR_GBL);
        out_8(&mspi->pram->rfcr, CPMFCR_EB | CPMFCR_GBL);
        out_be16(&mspi->pram->mrblr, SPI_MRBLR);
        out_be32(&mspi->pram->rstate, 0);
        out_be32(&mspi->pram->rdp, 0);
        out_be16(&mspi->pram->rbptr, 0);
        out_be16(&mspi->pram->rbc, 0);
        out_be32(&mspi->pram->rxtmp, 0);
        out_be32(&mspi->pram->tstate, 0);
        out_be32(&mspi->pram->tdp, 0);
        out_be16(&mspi->pram->tbptr, 0);
        out_be16(&mspi->pram->tbc, 0);
        out_be32(&mspi->pram->txtmp, 0);

        return 0;

err_dummy_rx:
        dma_unmap_single(dev, mspi->dma_dummy_tx, PAGE_SIZE, DMA_TO_DEVICE);
err_dummy_tx:
        cpm_muram_free(bds_ofs);
err_bds:
        cpm_muram_free(pram_ofs);
err_pram:
        fsl_spi_free_dummy_rx();
        return -ENOMEM;
}

static void fsl_spi_cpm_free(struct mpc8xxx_spi *mspi)
{
        struct device *dev = mspi->dev;

        if (!(mspi->flags & SPI_CPM_MODE))
                return;

        dma_unmap_single(dev, mspi->dma_dummy_rx, SPI_MRBLR, DMA_FROM_DEVICE);
        dma_unmap_single(dev, mspi->dma_dummy_tx, PAGE_SIZE, DMA_TO_DEVICE);
        cpm_muram_free(cpm_muram_offset(mspi->tx_bd));
        cpm_muram_free(cpm_muram_offset(mspi->pram));
        fsl_spi_free_dummy_rx();
}

static void fsl_spi_remove(struct mpc8xxx_spi *mspi)
{
        iounmap(mspi->reg_base);
        fsl_spi_cpm_free(mspi);
}

static struct spi_master * __devinit fsl_spi_probe(struct device *dev,
                struct resource *mem, unsigned int irq)
{
        struct fsl_spi_platform_data *pdata = dev->platform_data;
        struct spi_master *master;
        struct mpc8xxx_spi *mpc8xxx_spi;
        struct fsl_spi_reg *reg_base;
        u32 regval;
        int ret = 0;

        master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
        if (master == NULL) {
                ret = -ENOMEM;
                goto err;
        }

        dev_set_drvdata(dev, master);

        ret = mpc8xxx_spi_probe(dev, mem, irq);
        if (ret)
                goto err_probe;

        master->setup = fsl_spi_setup;

        mpc8xxx_spi = spi_master_get_devdata(master);
        mpc8xxx_spi->spi_do_one_msg = fsl_spi_do_one_msg;
        mpc8xxx_spi->spi_remove = fsl_spi_remove;


        ret = fsl_spi_cpm_init(mpc8xxx_spi);
        if (ret)
                goto err_cpm_init;

        if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
                mpc8xxx_spi->rx_shift = 16;
                mpc8xxx_spi->tx_shift = 24;
        }

        mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
        if (mpc8xxx_spi->reg_base == NULL) {
                ret = -ENOMEM;
                goto err_ioremap;
        }

        /* Register for SPI Interrupt */
        ret = request_irq(mpc8xxx_spi->irq, fsl_spi_irq,
                          0, "fsl_spi", mpc8xxx_spi);

        if (ret != 0)
                goto free_irq;

        reg_base = mpc8xxx_spi->reg_base;

        /* SPI controller initializations */
        mpc8xxx_spi_write_reg(&reg_base->mode, 0);
        mpc8xxx_spi_write_reg(&reg_base->mask, 0);
        mpc8xxx_spi_write_reg(&reg_base->command, 0);
        mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);

        /* Enable SPI interface */
        regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
        if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
                regval |= SPMODE_OP;

        mpc8xxx_spi_write_reg(&reg_base->mode, regval);

        ret = spi_register_master(master);
        if (ret < 0)
                goto unreg_master;

        dev_info(dev, "at 0x%p (irq = %d), %s mode\n", reg_base,
                 mpc8xxx_spi->irq, mpc8xxx_spi_strmode(mpc8xxx_spi->flags));

        return master;

unreg_master:
        free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
free_irq:
        iounmap(mpc8xxx_spi->reg_base);
err_ioremap:
        fsl_spi_cpm_free(mpc8xxx_spi);
err_cpm_init:
err_probe:
        spi_master_put(master);
err:
        return ERR_PTR(ret);
}

static void fsl_spi_cs_control(struct spi_device *spi, bool on)
{
        struct device *dev = spi->dev.parent;
        struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(dev->platform_data);
        u16 cs = spi->chip_select;
        int gpio = pinfo->gpios[cs];
        bool alow = pinfo->alow_flags[cs];

        gpio_set_value(gpio, on ^ alow);
}

static int of_fsl_spi_get_chipselects(struct device *dev)
{
        struct device_node *np = dev->of_node;
        struct fsl_spi_platform_data *pdata = dev->platform_data;
        struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
        unsigned int ngpios;
        int i = 0;
        int ret;

        ngpios = of_gpio_count(np);
        if (!ngpios) {
                /*
                 * SPI w/o chip-select line. One SPI device is still permitted
                 * though.
                 */
                pdata->max_chipselect = 1;
                return 0;
        }

        pinfo->gpios = kmalloc(ngpios * sizeof(*pinfo->gpios), GFP_KERNEL);
        if (!pinfo->gpios)
                return -ENOMEM;
        memset(pinfo->gpios, -1, ngpios * sizeof(*pinfo->gpios));

        pinfo->alow_flags = kzalloc(ngpios * sizeof(*pinfo->alow_flags),
                                    GFP_KERNEL);
        if (!pinfo->alow_flags) {
                ret = -ENOMEM;
                goto err_alloc_flags;
        }

        for (; i < ngpios; i++) {
                int gpio;
                enum of_gpio_flags flags;

                gpio = of_get_gpio_flags(np, i, &flags);
                if (!gpio_is_valid(gpio)) {
                        dev_err(dev, "invalid gpio #%d: %d\n", i, gpio);
                        ret = gpio;
                        goto err_loop;
                }

                ret = gpio_request(gpio, dev_name(dev));
                if (ret) {
                        dev_err(dev, "can't request gpio #%d: %d\n", i, ret);
                        goto err_loop;
                }

                pinfo->gpios[i] = gpio;
                pinfo->alow_flags[i] = flags & OF_GPIO_ACTIVE_LOW;

                ret = gpio_direction_output(pinfo->gpios[i],
                                            pinfo->alow_flags[i]);
                if (ret) {
                        dev_err(dev, "can't set output direction for gpio "
                                "#%d: %d\n", i, ret);
                        goto err_loop;
                }
        }

        pdata->max_chipselect = ngpios;
        pdata->cs_control = fsl_spi_cs_control;

        return 0;

err_loop:
        while (i >= 0) {
                if (gpio_is_valid(pinfo->gpios[i]))
                        gpio_free(pinfo->gpios[i]);
                i--;
        }

        kfree(pinfo->alow_flags);
        pinfo->alow_flags = NULL;
err_alloc_flags:
        kfree(pinfo->gpios);
        pinfo->gpios = NULL;
        return ret;
}

static int of_fsl_spi_free_chipselects(struct device *dev)
{
        struct fsl_spi_platform_data *pdata = dev->platform_data;
        struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
        int i;

        if (!pinfo->gpios)
                return 0;

        for (i = 0; i < pdata->max_chipselect; i++) {
                if (gpio_is_valid(pinfo->gpios[i]))
                        gpio_free(pinfo->gpios[i]);
        }

        kfree(pinfo->gpios);
        kfree(pinfo->alow_flags);
        return 0;
}

static int __devinit of_fsl_spi_probe(struct platform_device *ofdev)
{
        struct device *dev = &ofdev->dev;
        struct device_node *np = ofdev->dev.of_node;
        struct spi_master *master;
        struct resource mem;
        struct resource irq;
        int ret = -ENOMEM;

        ret = of_mpc8xxx_spi_probe(ofdev);
        if (ret)
                return ret;

        ret = of_fsl_spi_get_chipselects(dev);
        if (ret)
                goto err;

        ret = of_address_to_resource(np, 0, &mem);
        if (ret)
                goto err;

        ret = of_irq_to_resource(np, 0, &irq);
        if (!ret) {
                ret = -EINVAL;
                goto err;
        }

        master = fsl_spi_probe(dev, &mem, irq.start);
        if (IS_ERR(master)) {
                ret = PTR_ERR(master);
                goto err;
        }

        return 0;

err:
        of_fsl_spi_free_chipselects(dev);
        return ret;
}

static int __devexit of_fsl_spi_remove(struct platform_device *ofdev)
{
        int ret;

        ret = mpc8xxx_spi_remove(&ofdev->dev);
        if (ret)
                return ret;
        of_fsl_spi_free_chipselects(&ofdev->dev);
        return 0;
}

static const struct of_device_id of_fsl_spi_match[] = {
        { .compatible = "fsl,spi" },
        {}
};
MODULE_DEVICE_TABLE(of, of_fsl_spi_match);

static struct platform_driver of_fsl_spi_driver = {
        .driver = {
                .name = "fsl_spi",
                .owner = THIS_MODULE,
                .of_match_table = of_fsl_spi_match,
        },
        .probe          = of_fsl_spi_probe,
        .remove         = __devexit_p(of_fsl_spi_remove),
};

#ifdef CONFIG_MPC832x_RDB
/*
 * XXX XXX XXX
 * This is "legacy" platform driver, was used by the MPC8323E-RDB boards
 * only. The driver should go away soon, since newer MPC8323E-RDB's device
 * tree can work with OpenFirmware driver. But for now we support old trees
 * as well.
 */
static int __devinit plat_mpc8xxx_spi_probe(struct platform_device *pdev)
{
        struct resource *mem;
        int irq;
        struct spi_master *master;

        if (!pdev->dev.platform_data)
                return -EINVAL;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!mem)
                return -EINVAL;

        irq = platform_get_irq(pdev, 0);
        if (irq <= 0)
                return -EINVAL;

        master = fsl_spi_probe(&pdev->dev, mem, irq);
        if (IS_ERR(master))
                return PTR_ERR(master);
        return 0;
}

static int __devexit plat_mpc8xxx_spi_remove(struct platform_device *pdev)
{
        return mpc8xxx_spi_remove(&pdev->dev);
}

MODULE_ALIAS("platform:mpc8xxx_spi");
static struct platform_driver mpc8xxx_spi_driver = {
        .probe = plat_mpc8xxx_spi_probe,
        .remove = __devexit_p(plat_mpc8xxx_spi_remove),
        .driver = {
                .name = "mpc8xxx_spi",
                .owner = THIS_MODULE,
        },
};

static bool legacy_driver_failed;

static void __init legacy_driver_register(void)
{
        legacy_driver_failed = platform_driver_register(&mpc8xxx_spi_driver);
}

static void __exit legacy_driver_unregister(void)
{
        if (legacy_driver_failed)
                return;
        platform_driver_unregister(&mpc8xxx_spi_driver);
}
#else
static void __init legacy_driver_register(void) {}
static void __exit legacy_driver_unregister(void) {}
#endif /* CONFIG_MPC832x_RDB */

static int __init fsl_spi_init(void)
{
        legacy_driver_register();
        return platform_driver_register(&of_fsl_spi_driver);
}
module_init(fsl_spi_init);

static void __exit fsl_spi_exit(void)
{
        platform_driver_unregister(&of_fsl_spi_driver);
        legacy_driver_unregister();
}
module_exit(fsl_spi_exit);

MODULE_AUTHOR("Kumar Gala");
MODULE_DESCRIPTION("Simple Freescale SPI Driver");
MODULE_LICENSE("GPL");