[PATCH RESEND] mtd: cfi: Support early CFI fixups

[Aaron Sierra <asierra@xes-inc.com>]

Some CFI devices need fixups that affect the number of chips detected,
but the current fixup infrastructure (struct cfi_fixup and cfi_fixup())
does not cover this situation.

Introduce struct cfi_early_fixup and cfi_early_fixup() to fill the void
along with the fixup for S70GL02GS.

Without early fixups (top half of device cannot be written or erased):
  ff0000000.nor-boot: Found 1 x16 devices at 0x0 in 16-bit bank. <snip>
  Amd/Fujitsu Extended Query Table at 0x0040
    Amd/Fujitsu Extended Query version 1.5.
  number of CFI chips: 1

With early fixups (entire device can be written and erased):
  Bad S70GL02GS CFI data; adjust to detect 2 chips
  ff0000000.nor-boot: Found 1 x16 devices at 0x0 in 16-bit bank. <snip>
  ff0000000.nor-boot: Found 1 x16 devices at 0x8000000 in 16-bit bank
  Amd/Fujitsu Extended Query Table at 0x0040
    Amd/Fujitsu Extended Query version 1.5.
  number of CFI chips: 2

Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
---

 * Resent due to mailing list bounce
 * Compiled under 4.16. Tested under 4.1 and 3.12 (e5500 PowerPC)

 drivers/mtd/chips/cfi_probe.c | 18 ++++++++++++++++++
 drivers/mtd/chips/cfi_util.c  | 13 +++++++++++++
 include/linux/mtd/cfi.h       | 10 ++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/mtd/chips/cfi_probe.c b/drivers/mtd/chips/cfi_probe.c
index e8d0164..8b60aff 100644
--- a/drivers/mtd/chips/cfi_probe.c
+++ b/drivers/mtd/chips/cfi_probe.c
@@ -151,6 +151,22 @@ static int __xipram cfi_probe_chip(struct map_info *map, __u32 base,
 	return 1;
 }
 
+static void fixup_s70gl02gs_chips(struct cfi_private *cfi)
+{
+	/*
+	 * S70GL02GS flash reports a single 256 MiB chip, but is really made up
+	 * of two 128 MiB chips with 1024 sectors each.
+	 */
+	cfi->cfiq->DevSize = 27;
+	cfi->cfiq->EraseRegionInfo[0] = 0x20003ff;
+	pr_warn("Bad S70GL02GS CFI data; adjust to detect 2 chips\n");
+}
+
+static struct cfi_early_fixup cfi_early_fixup_table[] = {
+	{ CFI_MFR_AMD, 0x4801, fixup_s70gl02gs_chips },
+	{ 0, 0, NULL },
+};
+
 static int __xipram cfi_chip_setup(struct map_info *map,
 				   struct cfi_private *cfi)
 {
@@ -235,6 +251,8 @@ static int __xipram cfi_chip_setup(struct map_info *map,
 	cfi_qry_mode_off(base, map, cfi);
 	xip_allowed(base, map);
 
+	cfi_early_fixup(cfi, cfi_early_fixup_table);
+
 	printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank. Manufacturer ID %#08x Chip ID %#08x\n",
 	       map->name, cfi->interleave, cfi->device_type*8, base,
 	       map->bankwidth*8, cfi->mfr, cfi->id);
diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index 6f16552..e25d858 100644
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -333,6 +333,19 @@ __xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* n
 
 EXPORT_SYMBOL(cfi_read_pri);
 
+void cfi_early_fixup(struct cfi_private *cfi, struct cfi_early_fixup *fixups)
+{
+	struct cfi_early_fixup *f;
+
+	for (f = fixups; f->fixup; f++) {
+		if (((f->mfr == CFI_MFR_ANY) || (f->mfr == cfi->mfr)) &&
+		    ((f->id == CFI_ID_ANY) || (f->id == cfi->id))) {
+			f->fixup(cfi);
+		}
+	}
+}
+EXPORT_SYMBOL(cfi_early_fixup);
+
 void cfi_fixup(struct mtd_info *mtd, struct cfi_fixup *fixups)
 {
 	struct map_info *map = mtd->priv;
diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
index 9b57a9b..7d304db 100644
--- a/include/linux/mtd/cfi.h
+++ b/include/linux/mtd/cfi.h
@@ -353,6 +353,15 @@ void __xipram cfi_qry_mode_off(uint32_t base, struct map_info *map,
 
 struct cfi_extquery *cfi_read_pri(struct map_info *map, uint16_t adr, uint16_t size,
 			     const char* name);
+
+/* CFI fixup that can occur immediately after reading */
+struct cfi_early_fixup {
+	uint16_t mfr;
+	uint16_t id;
+	void (*fixup)(struct cfi_private *cfi);
+};
+
+/* CFI fixup that can only occur after MTD device exists */
 struct cfi_fixup {
 	uint16_t mfr;
 	uint16_t id;
@@ -380,6 +389,7 @@ struct cfi_fixup {
 #define CFI_MFR_TOSHIBA		0x0098
 #define CFI_MFR_WINBOND		0x00DA
 
+void cfi_early_fixup(struct cfi_private *cfi, struct cfi_early_fixup *fixups);
 void cfi_fixup(struct mtd_info *mtd, struct cfi_fixup* fixups);
 
 typedef int (*varsize_frob_t)(struct map_info *map, struct flchip *chip,
-- 
2.7.4