drivers/mtd/hbmc-am654.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
   4 // Author: Vignesh Raghavendra <vigneshr@ti.com>
   5
   6 #include <common.h>
   7 #include <asm/io.h>
   8 #include <dm.h>
   9 #include <regmap.h>
  10 #include <syscon.h>
  11
  12 #define FSS_SYSC_REG    0x4
  13
  14 #define HYPERBUS_CALIB_COUNT 25
  15
  16 struct am654_hbmc_priv {
  17         void __iomem *mmiobase;
  18         bool calibrated;
  19 };
  20
  21 /* Calibrate by looking for "QRY" string within the CFI space */
  22 static int am654_hyperbus_calibrate(struct udevice *dev)
  23 {
  24         struct am654_hbmc_priv *priv = dev_get_priv(dev);
  25         int count = HYPERBUS_CALIB_COUNT;
  26         int pass_count = 0;
  27         u16 qry[3];
  28
  29         if (priv->calibrated)
  30                 return 0;
  31
  32         writew(0xF0, priv->mmiobase);
  33         writew(0x98, priv->mmiobase + 0xaa);
  34
  35         while (count--) {
  36                 qry[0] = readw(priv->mmiobase + 0x20);
  37                 qry[1] = readw(priv->mmiobase + 0x22);
  38                 qry[2] = readw(priv->mmiobase + 0x24);
  39
  40                 if (qry[0] == 'Q' && qry[1] == 'R' && qry[2] == 'Y')
  41                         pass_count++;
  42                 else
  43                         pass_count = 0;
  44                 if (pass_count == 5)
  45                         break;
  46         }
  47         writew(0xF0, priv->mmiobase);
  48         writew(0xFF, priv->mmiobase);
  49
  50         return pass_count == 5;
  51 }
  52
  53 static int am654_select_hbmc(struct udevice *dev)
  54 {
  55         struct regmap *regmap = syscon_get_regmap(dev_get_parent(dev));
  56
  57         return regmap_update_bits(regmap, FSS_SYSC_REG, 0x2, 0x2);
  58 }
  59
  60 static int am654_hbmc_bind(struct udevice *dev)
  61 {
  62         return dm_scan_fdt_dev(dev);
  63 }
  64
  65 static int am654_hbmc_probe(struct udevice *dev)
  66 {
  67         struct am654_hbmc_priv *priv = dev_get_priv(dev);
  68         int ret;
  69
  70         priv->mmiobase = devfdt_remap_addr_index(dev, 1);
  71         if (dev_read_bool(dev, "mux-controls")) {
  72                 ret = am654_select_hbmc(dev);
  73                 if (ret) {
  74                         dev_err(dev, "Failed to select HBMC mux\n");
  75                         return ret;
  76                 }
  77         }
  78
  79         if (!priv->calibrated) {
  80                 ret = am654_hyperbus_calibrate(dev);
  81                 if (!ret) {
  82                         dev_err(dev, "Calibration Failed\n");
  83                         return -EIO;
  84                 }
  85         }
  86         priv->calibrated = true;
  87
  88         return 0;
  89 }
  90
  91 static const struct udevice_id am654_hbmc_dt_ids[] = {
  92         {
  93                 .compatible = "ti,am654-hbmc",
  94         },
  95         { /* end of table */ }
  96 };
  97
  98 U_BOOT_DRIVER(hbmc_am654) = {
  99         .name   = "hbmc-am654",
 100         .id     = UCLASS_MTD,
 101         .of_match = am654_hbmc_dt_ids,
 102         .probe = am654_hbmc_probe,
 103         .bind = am654_hbmc_bind,
 104         .priv_auto_alloc_size = sizeof(struct am654_hbmc_priv),
 105 };