mtd: spi-nor-core: Introduce flash-specific fixup hooks

Sometimes the information in a flash's SFDP tables is wrong. Sometimes
some information just can't be expressed in the SFDP table. So,
introduce the fixup hooks to allow tailoring settings for a specific
flash.

Three hooks are added: default_init, post_sfdp, and post_bfpt. These
allow tweaking the flash settings at different point in the probe
sequence. Since the hooks reside in nor->info, set that value just
before the call to spi_nor_init_params().

The hooks and at what points they are executed mimics Linux's spi-nor
framework. One major difference is that Linux puts the struct
spi_nor_fixups in nor->info. This is not possible in U-Boot because the
spi-nor-ids list is shared between spi-nor-core.c and spi-nor-tiny.c.
Since spi-nor-tiny shouldn't have those fixup hooks populated, add a
separate function that lets flashes populate their fixup hooks.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 312628c080a9ef5a86a688adbd5d6c39fdd30ee5..013a48d2efd77e35df23dc4fff278970f1770ec9 100644 (file)
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -152,6 +152,31 @@ struct sfdp_bfpt {
        u32     dwords[BFPT_DWORD_MAX];
 };
 
+/**
+ * struct spi_nor_fixups - SPI NOR fixup hooks
+ * @default_init: called after default flash parameters init. Used to tweak
+ *                flash parameters when information provided by the flash_info
+ *                table is incomplete or wrong.
+ * @post_bfpt: called after the BFPT table has been parsed
+ * @post_sfdp: called after SFDP has been parsed (is also called for SPI NORs
+ *             that do not support RDSFDP). Typically used to tweak various
+ *             parameters that could not be extracted by other means (i.e.
+ *             when information provided by the SFDP/flash_info tables are
+ *             incomplete or wrong).
+ *
+ * Those hooks can be used to tweak the SPI NOR configuration when the SFDP
+ * table is broken or not available.
+ */
+struct spi_nor_fixups {
+       void (*default_init)(struct spi_nor *nor);
+       int (*post_bfpt)(struct spi_nor *nor,
+                        const struct sfdp_parameter_header *bfpt_header,
+                        const struct sfdp_bfpt *bfpt,
+                        struct spi_nor_flash_parameter *params);
+       void (*post_sfdp)(struct spi_nor *nor,
+                         struct spi_nor_flash_parameter *params);
+};
+
 static int spi_nor_read_write_reg(struct spi_nor *nor, struct spi_mem_op
                *op, void *buf)
 {
@@ -1751,6 +1776,18 @@ static const struct sfdp_bfpt_erase sfdp_bfpt_erases[] = {
 
 static int spi_nor_hwcaps_read2cmd(u32 hwcaps);
 
+static int
+spi_nor_post_bfpt_fixups(struct spi_nor *nor,
+                        const struct sfdp_parameter_header *bfpt_header,
+                        const struct sfdp_bfpt *bfpt,
+                        struct spi_nor_flash_parameter *params)
+{
+       if (nor->fixups && nor->fixups->post_bfpt)
+               return nor->fixups->post_bfpt(nor, bfpt_header, bfpt, params);
+
+       return 0;
+}
+
 /**
  * spi_nor_parse_bfpt() - read and parse the Basic Flash Parameter Table.
  * @nor:               pointer to a 'struct spi_nor'
@@ -1889,7 +1926,8 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 
        /* Stop here if not JESD216 rev A or later. */
        if (bfpt_header->length < BFPT_DWORD_MAX)
-               return 0;
+               return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt,
+                                               params);
 
        /* Page size: this field specifies 'N' so the page size = 2^N bytes. */
        params->page_size = bfpt.dwords[BFPT_DWORD(11)];
@@ -1922,7 +1960,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
                return -EINVAL;
        }
 
-       return 0;
+       return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt, params);
 }
 
 /**
@@ -2085,6 +2123,29 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
 }
 #endif /* SPI_FLASH_SFDP_SUPPORT */
 
+/**
+ * spi_nor_post_sfdp_fixups() - Updates the flash's parameters and settings
+ * after SFDP has been parsed (is also called for SPI NORs that do not
+ * support RDSFDP).
+ * @nor:       pointer to a 'struct spi_nor'
+ *
+ * Typically used to tweak various parameters that could not be extracted by
+ * other means (i.e. when information provided by the SFDP/flash_info tables
+ * are incomplete or wrong).
+ */
+static void spi_nor_post_sfdp_fixups(struct spi_nor *nor,
+                                    struct spi_nor_flash_parameter *params)
+{
+       if (nor->fixups && nor->fixups->post_sfdp)
+               nor->fixups->post_sfdp(nor, params);
+}
+
+static void spi_nor_default_init_fixups(struct spi_nor *nor)
+{
+       if (nor->fixups && nor->fixups->default_init)
+               nor->fixups->default_init(nor);
+}
+
 static int spi_nor_init_params(struct spi_nor *nor,
                               const struct flash_info *info,
                               struct spi_nor_flash_parameter *params)
@@ -2164,6 +2225,8 @@ static int spi_nor_init_params(struct spi_nor *nor,
                }
        }
 
+       spi_nor_default_init_fixups(nor);
+
        /* Override the parameters with data read from SFDP tables. */
        nor->addr_width = 0;
        nor->mtd.erasesize = 0;
@@ -2180,6 +2243,8 @@ static int spi_nor_init_params(struct spi_nor *nor,
                }
        }
 
+       spi_nor_post_sfdp_fixups(nor, params);
+
        return 0;
 }
 
@@ -2428,6 +2493,10 @@ static int spi_nor_init(struct spi_nor *nor)
        return 0;
 }
 
+void spi_nor_set_fixups(struct spi_nor *nor)
+{
+}
+
 int spi_nor_scan(struct spi_nor *nor)
 {
        struct spi_nor_flash_parameter params;
@@ -2476,6 +2545,10 @@ int spi_nor_scan(struct spi_nor *nor)
        info = spi_nor_read_id(nor);
        if (IS_ERR_OR_NULL(info))
                return -ENOENT;
+       nor->info = info;
+
+       spi_nor_set_fixups(nor);
+
        /* Parse the Serial Flash Discoverable Parameters table. */
        ret = spi_nor_init_params(nor, info, &params);
        if (ret)
@@ -2578,7 +2651,6 @@ int spi_nor_scan(struct spi_nor *nor)
        }
 
        /* Send all the required SPI flash commands to initialize device */
-       nor->info = info;
        ret = spi_nor_init(nor);
        if (ret)
                return ret;

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 47a2eced6967286d69ec1e48e91eff967f548139..b2e9e0895b8d28856a801ca9d1b21426f9bf8bfa 100644 (file)
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -416,6 +416,7 @@ struct spi_flash {
  * @write_proto:       the SPI protocol for write operations
  * @reg_proto          the SPI protocol for read_reg/write_reg/erase operations
  * @cmd_buf:           used by the write_reg
+ * @fixups:            flash-specific fixup hooks.
  * @prepare:           [OPTIONAL] do some preparations for the
  *                     read/write/erase/lock/unlock operations
  * @unprepare:         [OPTIONAL] do some post work after the
@@ -457,6 +458,7 @@ struct spi_nor {
        bool                    sst_write_second;
        u32                     flags;
        u8                      cmd_buf[SPI_NOR_MAX_CMD_SIZE];
+       struct spi_nor_fixups   *fixups;
 
        int (*setup)(struct spi_nor *nor, const struct flash_info *info,
                     const struct spi_nor_flash_parameter *params,