drivers/ata/ahci_da850.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DaVinci DA850 AHCI SATA platform driver
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/pm.h>
   9 #include <linux/device.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/libata.h>
  12 #include <linux/ahci_platform.h>
  13 #include "ahci.h"
  14
  15 #define DRV_NAME                "ahci_da850"
  16 #define HARDRESET_RETRIES       5
  17
  18 /* SATA PHY Control Register offset from AHCI base */
  19 #define SATA_P0PHYCR_REG        0x178
  20
  21 #define SATA_PHY_MPY(x)         ((x) << 0)
  22 #define SATA_PHY_LOS(x)         ((x) << 6)
  23 #define SATA_PHY_RXCDR(x)       ((x) << 10)
  24 #define SATA_PHY_RXEQ(x)        ((x) << 13)
  25 #define SATA_PHY_TXSWING(x)     ((x) << 19)
  26 #define SATA_PHY_ENPLL(x)       ((x) << 31)
  27
  28 static void da850_sata_init(struct device *dev, void __iomem *pwrdn_reg,
  29                             void __iomem *ahci_base, u32 mpy)
  30 {
  31         unsigned int val;
  32
  33         /* Enable SATA clock receiver */
  34         val = readl(pwrdn_reg);
  35         val &= ~BIT(0);
  36         writel(val, pwrdn_reg);
  37
  38         val = SATA_PHY_MPY(mpy) | SATA_PHY_LOS(1) | SATA_PHY_RXCDR(4) |
  39               SATA_PHY_RXEQ(1) | SATA_PHY_TXSWING(3) | SATA_PHY_ENPLL(1);
  40
  41         writel(val, ahci_base + SATA_P0PHYCR_REG);
  42 }
  43
  44 static u32 ahci_da850_calculate_mpy(unsigned long refclk_rate)
  45 {
  46         u32 pll_output = 1500000000, needed;
  47
  48         /*
  49          * We need to determine the value of the multiplier (MPY) bits.
  50          * In order to include the 12.5 multiplier we need to first divide
  51          * the refclk rate by ten.
  52          *
  53          * __div64_32() turned out to be unreliable, sometimes returning
  54          * false results.
  55          */
  56         WARN((refclk_rate % 10) != 0, "refclk must be divisible by 10");
  57         needed = pll_output / (refclk_rate / 10);
  58
  59         /*
  60          * What we have now is (multiplier * 10).
  61          *
  62          * Let's determine the actual register value we need to write.
  63          */
  64
  65         switch (needed) {
  66         case 50:
  67                 return 0x1;
  68         case 60:
  69                 return 0x2;
  70         case 80:
  71                 return 0x4;
  72         case 100:
  73                 return 0x5;
  74         case 120:
  75                 return 0x6;
  76         case 125:
  77                 return 0x7;
  78         case 150:
  79                 return 0x8;
  80         case 200:
  81                 return 0x9;
  82         case 250:
  83                 return 0xa;
  84         default:
  85                 /*
  86                  * We should have divided evenly - if not, return an invalid
  87                  * value.
  88                  */
  89                 return 0;
  90         }
  91 }
  92
  93 static int ahci_da850_softreset(struct ata_link *link,
  94                                 unsigned int *class, unsigned long deadline)
  95 {
  96         int pmp, ret;
  97
  98         pmp = sata_srst_pmp(link);
  99
 100         /*
 101          * There's an issue with the SATA controller on da850 SoCs: if we
 102          * enable Port Multiplier support, but the drive is connected directly
 103          * to the board, it can't be detected. As a workaround: if PMP is
 104          * enabled, we first call ahci_do_softreset() and pass it the result of
 105          * sata_srst_pmp(). If this call fails, we retry with pmp = 0.
 106          */
 107         ret = ahci_do_softreset(link, class, pmp, deadline, ahci_check_ready);
 108         if (pmp && ret == -EBUSY)
 109                 return ahci_do_softreset(link, class, 0,
 110                                          deadline, ahci_check_ready);
 111
 112         return ret;
 113 }
 114
 115 static int ahci_da850_hardreset(struct ata_link *link,
 116                                 unsigned int *class, unsigned long deadline)
 117 {
 118         int ret, retry = HARDRESET_RETRIES;
 119         bool online;
 120
 121         /*
 122          * In order to correctly service the LCD controller of the da850 SoC,
 123          * we increased the PLL0 frequency to 456MHz from the default 300MHz.
 124          *
 125          * This made the SATA controller unstable and the hardreset operation
 126          * does not always succeed the first time. Before really giving up to
 127          * bring up the link, retry the reset a couple times.
 128          */
 129         do {
 130                 ret = ahci_do_hardreset(link, class, deadline, &online);
 131                 if (online)
 132                         return ret;
 133         } while (retry--);
 134
 135         return ret;
 136 }
 137
 138 static struct ata_port_operations ahci_da850_port_ops = {
 139         .inherits = &ahci_platform_ops,
 140         .softreset = ahci_da850_softreset,
 141         /*
 142          * No need to override .pmp_softreset - it's only used for actual
 143          * PMP-enabled ports.
 144          */
 145         .hardreset = ahci_da850_hardreset,
 146         .pmp_hardreset = ahci_da850_hardreset,
 147 };
 148
 149 static const struct ata_port_info ahci_da850_port_info = {
 150         .flags          = AHCI_FLAG_COMMON,
 151         .pio_mask       = ATA_PIO4,
 152         .udma_mask      = ATA_UDMA6,
 153         .port_ops       = &ahci_da850_port_ops,
 154 };
 155
 156 static struct scsi_host_template ahci_platform_sht = {
 157         AHCI_SHT(DRV_NAME),
 158 };
 159
 160 static int ahci_da850_probe(struct platform_device *pdev)
 161 {
 162         struct device *dev = &pdev->dev;
 163         struct ahci_host_priv *hpriv;
 164         void __iomem *pwrdn_reg;
 165         struct resource *res;
 166         struct clk *clk;
 167         u32 mpy;
 168         int rc;
 169
 170         hpriv = ahci_platform_get_resources(pdev, 0);
 171         if (IS_ERR(hpriv))
 172                 return PTR_ERR(hpriv);
 173
 174         /*
 175          * Internally ahci_platform_get_resources() calls clk_get(dev, NULL)
 176          * when trying to obtain the functional clock. This SATA controller
 177          * uses two clocks for which we specify two connection ids. If we don't
 178          * have the functional clock at this point - call clk_get() again with
 179          * con_id = "fck".
 180          */
 181         if (!hpriv->clks[0]) {
 182                 clk = clk_get(dev, "fck");
 183                 if (IS_ERR(clk))
 184                         return PTR_ERR(clk);
 185
 186                 hpriv->clks[0] = clk;
 187         }
 188
 189         /*
 190          * The second clock used by ahci-da850 is the external REFCLK. If we
 191          * didn't get it from ahci_platform_get_resources(), let's try to
 192          * specify the con_id in clk_get().
 193          */
 194         if (!hpriv->clks[1]) {
 195                 clk = clk_get(dev, "refclk");
 196                 if (IS_ERR(clk)) {
 197                         dev_err(dev, "unable to obtain the reference clock");
 198                         return -ENODEV;
 199                 }
 200
 201                 hpriv->clks[1] = clk;
 202         }
 203
 204         mpy = ahci_da850_calculate_mpy(clk_get_rate(hpriv->clks[1]));
 205         if (mpy == 0) {
 206                 dev_err(dev, "invalid REFCLK multiplier value: 0x%x", mpy);
 207                 return -EINVAL;
 208         }
 209
 210         rc = ahci_platform_enable_resources(hpriv);
 211         if (rc)
 212                 return rc;
 213
 214         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 215         if (!res) {
 216                 rc = -ENODEV;
 217                 goto disable_resources;
 218         }
 219
 220         pwrdn_reg = devm_ioremap(dev, res->start, resource_size(res));
 221         if (!pwrdn_reg) {
 222                 rc = -ENOMEM;
 223                 goto disable_resources;
 224         }
 225
 226         da850_sata_init(dev, pwrdn_reg, hpriv->mmio, mpy);
 227
 228         rc = ahci_platform_init_host(pdev, hpriv, &ahci_da850_port_info,
 229                                      &ahci_platform_sht);
 230         if (rc)
 231                 goto disable_resources;
 232
 233         return 0;
 234 disable_resources:
 235         ahci_platform_disable_resources(hpriv);
 236         return rc;
 237 }
 238
 239 static SIMPLE_DEV_PM_OPS(ahci_da850_pm_ops, ahci_platform_suspend,
 240                          ahci_platform_resume);
 241
 242 static const struct of_device_id ahci_da850_of_match[] = {
 243         { .compatible = "ti,da850-ahci", },
 244         { },
 245 };
 246 MODULE_DEVICE_TABLE(of, ahci_da850_of_match);
 247
 248 static struct platform_driver ahci_da850_driver = {
 249         .probe = ahci_da850_probe,
 250         .remove = ata_platform_remove_one,
 251         .driver = {
 252                 .name = DRV_NAME,
 253                 .of_match_table = ahci_da850_of_match,
 254                 .pm = &ahci_da850_pm_ops,
 255         },
 256 };
 257 module_platform_driver(ahci_da850_driver);
 258
 259 MODULE_DESCRIPTION("DaVinci DA850 AHCI SATA platform driver");
 260 MODULE_AUTHOR("Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>");
 261 MODULE_LICENSE("GPL");