drivers/mtd/hbmc-am654.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (C) 2019 Texas Instruments Incorporated - https://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 #include <dm/device_compat.h>
  12
  13 #define FSS_SYSC_REG    0x4
  14
  15 #define HYPERBUS_CALIB_COUNT 25
  16
  17 struct am654_hbmc_priv {
  18         void __iomem *mmiobase;
  19         bool calibrated;
  20 };
  21
  22 /* Calibrate by looking for "QRY" string within the CFI space */
  23 static int am654_hyperbus_calibrate(struct udevice *dev)
  24 {
  25         struct am654_hbmc_priv *priv = dev_get_priv(dev);
  26         int count = HYPERBUS_CALIB_COUNT;
  27         int pass_count = 0;
  28         u16 qry[3];
  29
  30         if (priv->calibrated)
  31                 return 0;
  32
  33         writew(0xF0, priv->mmiobase);
  34         writew(0x98, priv->mmiobase + 0xaa);
  35
  36         while (count--) {
  37                 qry[0] = readw(priv->mmiobase + 0x20);
  38                 qry[1] = readw(priv->mmiobase + 0x22);
  39                 qry[2] = readw(priv->mmiobase + 0x24);
  40
  41                 if (qry[0] == 'Q' && qry[1] == 'R' && qry[2] == 'Y')
  42                         pass_count++;
  43                 else
  44                         pass_count = 0;
  45                 if (pass_count == 5)
  46                         break;
  47         }
  48         writew(0xF0, priv->mmiobase);
  49         writew(0xFF, priv->mmiobase);
  50
  51         return pass_count == 5;
  52 }
  53
  54 static int am654_select_hbmc(struct udevice *dev)
  55 {
  56         struct regmap *regmap = syscon_get_regmap(dev_get_parent(dev));
  57
  58         return regmap_update_bits(regmap, FSS_SYSC_REG, 0x2, 0x2);
  59 }
  60
  61 static int am654_hbmc_bind(struct udevice *dev)
  62 {
  63         return dm_scan_fdt_dev(dev);
  64 }
  65
  66 static int am654_hbmc_probe(struct udevice *dev)
  67 {
  68         struct am654_hbmc_priv *priv = dev_get_priv(dev);
  69         int ret;
  70
  71         priv->mmiobase = devfdt_remap_addr_index(dev, 1);
  72         if (dev_read_bool(dev, "mux-controls")) {
  73                 ret = am654_select_hbmc(dev);
  74                 if (ret) {
  75                         dev_err(dev, "Failed to select HBMC mux\n");
  76                         return ret;
  77                 }
  78         }
  79
  80         if (!priv->calibrated) {
  81                 ret = am654_hyperbus_calibrate(dev);
  82                 if (!ret) {
  83                         dev_err(dev, "Calibration Failed\n");
  84                         return -EIO;
  85                 }
  86         }
  87         priv->calibrated = true;
  88
  89         return 0;
  90 }
  91
  92 static const struct udevice_id am654_hbmc_dt_ids[] = {
  93         {
  94                 .compatible = "ti,am654-hbmc",
  95         },
  96         { /* end of table */ }
  97 };
  98
  99 U_BOOT_DRIVER(hbmc_am654) = {
 100         .name   = "hbmc-am654",
 101         .id     = UCLASS_MTD,
 102         .of_match = am654_hbmc_dt_ids,
 103         .probe = am654_hbmc_probe,
 104         .bind = am654_hbmc_bind,
 105         .priv_auto      = sizeof(struct am654_hbmc_priv),
 106 };