drivers/mtd/maps/physmap-gemini.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Cortina Systems Gemini OF physmap add-on
   4  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   5  *
   6  * This SoC has an elaborate flash control register, so we need to
   7  * detect and set it up when booting on this platform.
   8  */
   9 #include <linux/export.h>
  10 #include <linux/of.h>
  11 #include <linux/of_device.h>
  12 #include <linux/mtd/map.h>
  13 #include <linux/mtd/xip.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/regmap.h>
  16 #include <linux/bitops.h>
  17 #include <linux/pinctrl/consumer.h>
  18 #include "physmap-gemini.h"
  19
  20 /*
  21  * The Flash-relevant parts of the global status register
  22  * These would also be relevant for a NAND driver.
  23  */
  24 #define GLOBAL_STATUS                   0x04
  25 #define FLASH_TYPE_MASK                 (0x3 << 24)
  26 #define FLASH_TYPE_NAND_2K              (0x3 << 24)
  27 #define FLASH_TYPE_NAND_512             (0x2 << 24)
  28 #define FLASH_TYPE_PARALLEL             (0x1 << 24)
  29 #define FLASH_TYPE_SERIAL               (0x0 << 24)
  30 /* if parallel */
  31 #define FLASH_WIDTH_16BIT               (1 << 23)       /* else 8 bit */
  32 /* if serial */
  33 #define FLASH_ATMEL                     (1 << 23)       /* else STM */
  34
  35 #define FLASH_SIZE_MASK                 (0x3 << 21)
  36 #define NAND_256M                       (0x3 << 21)     /* and more */
  37 #define NAND_128M                       (0x2 << 21)
  38 #define NAND_64M                        (0x1 << 21)
  39 #define NAND_32M                        (0x0 << 21)
  40 #define ATMEL_16M                       (0x3 << 21)     /* and more */
  41 #define ATMEL_8M                        (0x2 << 21)
  42 #define ATMEL_4M_2M                     (0x1 << 21)
  43 #define ATMEL_1M                        (0x0 << 21)     /* and less */
  44 #define STM_32M                         (1 << 22)       /* and more */
  45 #define STM_16M                         (0 << 22)       /* and less */
  46
  47 #define FLASH_PARALLEL_HIGH_PIN_CNT     (1 << 20)       /* else low pin cnt */
  48
  49 static const struct of_device_id syscon_match[] = {
  50         { .compatible = "cortina,gemini-syscon" },
  51         { },
  52 };
  53
  54 struct gemini_flash {
  55         struct device *dev;
  56         struct pinctrl *p;
  57         struct pinctrl_state *enabled_state;
  58         struct pinctrl_state *disabled_state;
  59 };
  60
  61 /* Static local state */
  62 static struct gemini_flash *gf;
  63
  64 static void gemini_flash_enable_pins(void)
  65 {
  66         int ret;
  67
  68         if (IS_ERR(gf->enabled_state))
  69                 return;
  70         ret = pinctrl_select_state(gf->p, gf->enabled_state);
  71         if (ret)
  72                 dev_err(gf->dev, "failed to enable pins\n");
  73 }
  74
  75 static void gemini_flash_disable_pins(void)
  76 {
  77         int ret;
  78
  79         if (IS_ERR(gf->disabled_state))
  80                 return;
  81         ret = pinctrl_select_state(gf->p, gf->disabled_state);
  82         if (ret)
  83                 dev_err(gf->dev, "failed to disable pins\n");
  84 }
  85
  86 static map_word __xipram gemini_flash_map_read(struct map_info *map,
  87                                                unsigned long ofs)
  88 {
  89         map_word ret;
  90
  91         gemini_flash_enable_pins();
  92         ret = inline_map_read(map, ofs);
  93         gemini_flash_disable_pins();
  94
  95         return ret;
  96 }
  97
  98 static void __xipram gemini_flash_map_write(struct map_info *map,
  99                                             const map_word datum,
 100                                             unsigned long ofs)
 101 {
 102         gemini_flash_enable_pins();
 103         inline_map_write(map, datum, ofs);
 104         gemini_flash_disable_pins();
 105 }
 106
 107 static void __xipram gemini_flash_map_copy_from(struct map_info *map,
 108                                                 void *to, unsigned long from,
 109                                                 ssize_t len)
 110 {
 111         gemini_flash_enable_pins();
 112         inline_map_copy_from(map, to, from, len);
 113         gemini_flash_disable_pins();
 114 }
 115
 116 static void __xipram gemini_flash_map_copy_to(struct map_info *map,
 117                                               unsigned long to,
 118                                               const void *from, ssize_t len)
 119 {
 120         gemini_flash_enable_pins();
 121         inline_map_copy_to(map, to, from, len);
 122         gemini_flash_disable_pins();
 123 }
 124
 125 int of_flash_probe_gemini(struct platform_device *pdev,
 126                           struct device_node *np,
 127                           struct map_info *map)
 128 {
 129         struct regmap *rmap;
 130         struct device *dev = &pdev->dev;
 131         u32 val;
 132         int ret;
 133
 134         /* Multiplatform guard */
 135         if (!of_device_is_compatible(np, "cortina,gemini-flash"))
 136                 return 0;
 137
 138         gf = devm_kzalloc(dev, sizeof(*gf), GFP_KERNEL);
 139         if (!gf)
 140                 return -ENOMEM;
 141         gf->dev = dev;
 142
 143         rmap = syscon_regmap_lookup_by_phandle(np, "syscon");
 144         if (IS_ERR(rmap)) {
 145                 dev_err(dev, "no syscon\n");
 146                 return PTR_ERR(rmap);
 147         }
 148
 149         ret = regmap_read(rmap, GLOBAL_STATUS, &val);
 150         if (ret) {
 151                 dev_err(dev, "failed to read global status register\n");
 152                 return -ENODEV;
 153         }
 154         dev_dbg(dev, "global status reg: %08x\n", val);
 155
 156         /*
 157          * It would be contradictory if a physmap flash was NOT parallel.
 158          */
 159         if ((val & FLASH_TYPE_MASK) != FLASH_TYPE_PARALLEL) {
 160                 dev_err(dev, "flash is not parallel\n");
 161                 return -ENODEV;
 162         }
 163
 164         /*
 165          * Complain if DT data and hardware definition is different.
 166          */
 167         if (val & FLASH_WIDTH_16BIT) {
 168                 if (map->bankwidth != 2)
 169                         dev_warn(dev, "flash hardware say flash is 16 bit wide but DT says it is %d bits wide\n",
 170                                  map->bankwidth * 8);
 171         } else {
 172                 if (map->bankwidth != 1)
 173                         dev_warn(dev, "flash hardware say flash is 8 bit wide but DT says it is %d bits wide\n",
 174                                  map->bankwidth * 8);
 175         }
 176
 177         gf->p = devm_pinctrl_get(dev);
 178         if (IS_ERR(gf->p)) {
 179                 dev_err(dev, "no pinctrl handle\n");
 180                 ret = PTR_ERR(gf->p);
 181                 return ret;
 182         }
 183
 184         gf->enabled_state = pinctrl_lookup_state(gf->p, "enabled");
 185         if (IS_ERR(gf->enabled_state))
 186                 dev_err(dev, "no enabled pin control state\n");
 187
 188         gf->disabled_state = pinctrl_lookup_state(gf->p, "disabled");
 189         if (IS_ERR(gf->enabled_state)) {
 190                 dev_err(dev, "no disabled pin control state\n");
 191         } else {
 192                 ret = pinctrl_select_state(gf->p, gf->disabled_state);
 193                 if (ret)
 194                         dev_err(gf->dev, "failed to disable pins\n");
 195         }
 196
 197         map->read = gemini_flash_map_read;
 198         map->write = gemini_flash_map_write;
 199         map->copy_from = gemini_flash_map_copy_from;
 200         map->copy_to = gemini_flash_map_copy_to;
 201
 202         dev_info(dev, "initialized Gemini-specific physmap control\n");
 203
 204         return 0;
 205 }