mtd: nand: add common DT init code

These are already-documented common bindings for NAND chips. Let's
handle them in nand_base.

If NAND controller drivers need to act on this data before bringing up
the NAND chip (e.g., fill out ECC callback functions, change HW modes,
etc.), then they can do so between calling nand_scan_ident() and
nand_scan_tail().

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 0afe76315c384cc8b5993a35d3f70e148e780de3..c4619e3ac4ab2194947c253de81f5a054401857e 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -48,6 +48,7 @@
 #include <linux/leds.h>
 #include <linux/io.h>
 #include <linux/mtd/partitions.h>
+#include <linux/of_mtd.h>
 
 /* Define default oob placement schemes for large and small page devices */
 static struct nand_ecclayout nand_oob_8 = {
@@ -3795,6 +3796,39 @@ ident_done:
        return type;
 }
 
+static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip,
+                       struct device_node *dn)
+{
+       int ecc_mode, ecc_strength, ecc_step;
+
+       if (of_get_nand_bus_width(dn) == 16)
+               chip->options |= NAND_BUSWIDTH_16;
+
+       if (of_get_nand_on_flash_bbt(dn))
+               chip->bbt_options |= NAND_BBT_USE_FLASH;
+
+       ecc_mode = of_get_nand_ecc_mode(dn);
+       ecc_strength = of_get_nand_ecc_strength(dn);
+       ecc_step = of_get_nand_ecc_step_size(dn);
+
+       if ((ecc_step >= 0 && !(ecc_strength >= 0)) ||
+           (!(ecc_step >= 0) && ecc_strength >= 0)) {
+               pr_err("must set both strength and step size in DT\n");
+               return -EINVAL;
+       }
+
+       if (ecc_mode >= 0)
+               chip->ecc.mode = ecc_mode;
+
+       if (ecc_strength >= 0)
+               chip->ecc.strength = ecc_strength;
+
+       if (ecc_step > 0)
+               chip->ecc.size = ecc_step;
+
+       return 0;
+}
+
 /**
  * nand_scan_ident - [NAND Interface] Scan for the NAND device
  * @mtd: MTD device structure
@@ -3812,6 +3846,13 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
        int i, nand_maf_id, nand_dev_id;
        struct nand_chip *chip = mtd->priv;
        struct nand_flash_dev *type;
+       int ret;
+
+       if (chip->dn) {
+               ret = nand_dt_init(mtd, chip, chip->dn);
+               if (ret)
+                       return ret;
+       }
 
        /* Set the default functions */
        nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16);

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 6c51876941f3688b8a999bef79c03141f489d7bf..f25e2bdd188c94643efc0f3a94c7c67de81897aa 100644 (file)
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -26,6 +26,8 @@
 
 struct mtd_info;
 struct nand_flash_dev;
+struct device_node;
+
 /* Scan and identify a NAND device */
 extern int nand_scan(struct mtd_info *mtd, int max_chips);
 /*
@@ -542,6 +544,7 @@ struct nand_buffers {
  *                     flash device
  * @IO_ADDR_W:         [BOARDSPECIFIC] address to write the 8 I/O lines of the
  *                     flash device.
+ * @dn:                        [BOARDSPECIFIC] device node describing this instance
  * @read_byte:         [REPLACEABLE] read one byte from the chip
  * @read_word:         [REPLACEABLE] read one word from the chip
  * @write_byte:                [REPLACEABLE] write a single byte to the chip on the
@@ -644,6 +647,8 @@ struct nand_chip {
        void __iomem *IO_ADDR_R;
        void __iomem *IO_ADDR_W;
 
+       struct device_node *dn;
+
        uint8_t (*read_byte)(struct mtd_info *mtd);
        u16 (*read_word)(struct mtd_info *mtd);
        void (*write_byte)(struct mtd_info *mtd, uint8_t byte);