arm: tegra: fuse: fix multiple issues

- handle scenarios when the number of fuses burnt
  is a odd number
- wait for the fuse bock to be idle before issuing
  any command
- burning of master_enb fuse is not required to be
  done according to the guidelines

Bug 823552

Change-Id: I04477dcfae610aed3e2072adfc48ebd7212449ad
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Reviewed-on: http://git-master/r/35883
Reviewed-by: Andy Carman <acarman@nvidia.com>
Tested-by: Andy Carman <acarman@nvidia.com>
Reviewed-by: Venkata (Muni) Anda <vanda@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

1 files changed, 19 insertions, 19 deletions

diff --git a/arch/arm/mach-tegra/tegra2_fuse.c b/arch/arm/mach-tegra/tegra2_fuse.c
index 97cf6e070f2b..4210b0d9ef33 100644
--- a/arch/arm/mach-tegra/tegra2_fuse.c
+++ b/arch/arm/mach-tegra/tegra2_fuse.c
@@ -206,13 +206,6 @@ static struct param_info fuse_info_tbl[] = {
 	[SBK_DEVKEY_STATUS] = {
 		.sz = SBK_DEVKEY_STATUS_SZ,
 	},
-	[MASTER_ENB] = {
-		.addr = &master_enable,
-		.sz = sizeof(u8),
-		.start_off = 0x0,
-		.start_bit = 0,
-		.nbits = 1,
-	},
 };
 
 static void wait_for_idle(void)
@@ -233,6 +226,7 @@ static u32 fuse_cmd_read(u32 addr)
 {
 	u32 reg;
 
+	wait_for_idle();
 	tegra_fuse_writel(addr, FUSE_REG_ADDR);
 	reg = tegra_fuse_readl(FUSE_CTRL);
 	reg &= ~FUSE_CMD_MASK;
@@ -248,6 +242,7 @@ static void fuse_cmd_write(u32 value, u32 addr)
 {
 	u32 reg;
 
+	wait_for_idle();
 	tegra_fuse_writel(addr, FUSE_REG_ADDR);
 	tegra_fuse_writel(value, FUSE_REG_WRITE);
 
@@ -262,6 +257,7 @@ static void fuse_cmd_sense(void)
 {
 	u32 reg;
 
+	wait_for_idle();
 	reg = tegra_fuse_readl(FUSE_CTRL);
 	reg &= ~FUSE_CMD_MASK;
 	reg |= FUSE_SENSE;
@@ -401,10 +397,6 @@ static void populate_fuse_arrs(struct fuse_data *info, u32 flags)
 	memset(fuse_pgm_data, 0, sizeof(fuse_pgm_data));
 	memset(fuse_pgm_mask, 0, sizeof(fuse_pgm_mask));
 
-	/* enable program bit */
-	data = 1;
-	set_fuse(MASTER_ENB, &data);
-
 	if ((flags & FLAGS_ODMRSVD)) {
 		set_fuse(ODM_RSVD, info->odm_rsvd);
 		flags &= ~FLAGS_ODMRSVD;
@@ -610,10 +602,6 @@ int tegra_fuse_program(struct fuse_data *pgm_data, u32 flags)
 	pr_debug("%s: use %d programming cycles\n", __func__, fuse_pgm_cycles[index]);
 	fuse_program_array(fuse_pgm_cycles[index]);
 
-	/* disable program bit */
-	reg = 0;
-	set_fuse(MASTER_ENB, &reg);
-
 	memset(&fuse_info, 0, sizeof(fuse_info));
 	regulator_disable(vdd_fuse);
 	mutex_unlock(&fuse_lock);
@@ -663,6 +651,7 @@ static ssize_t fuse_store(struct kobject *kobj, struct kobj_attribute *attr,
 {
 	enum fuse_io_param param = fuse_name_to_param(attr->attr.name);
 	int ret, i = 0;
+	int orig_count = count;
 	struct fuse_data data = {0};
 	u32 *raw_data = ((u32 *)&data) + fuse_info_tbl[param].data_offset;
 	u8 *raw_byte_data = (u8 *)raw_data;
@@ -692,13 +681,24 @@ static ssize_t fuse_store(struct kobject *kobj, struct kobj_attribute *attr,
 	wake_lock_init(&fuse_wk_lock, WAKE_LOCK_SUSPEND, "fuse_wk_lock");
 	wake_lock(&fuse_wk_lock);
 
+	/* we need to fit each character into a single nibble */
 	raw_byte_data += DIV_ROUND_UP(count, 2) - 1;
-	for (i = 0; i < DIV_ROUND_UP(count, 2); i++, buf++) {
+
+	if (count % 2) {
 		*raw_byte_data = char_to_xdigit(*buf);
-		*raw_byte_data <<= 4;
 		buf++;
-		*raw_byte_data |= (char_to_xdigit(*buf) & 0xF);
 		raw_byte_data--;
+		count--;
+	}
+
+	for (i = 1; i <= count; i++, buf++) {
+		if (i % 2) {
+			*raw_byte_data = char_to_xdigit(*buf);
+		} else {
+			*raw_byte_data <<= 4;
+			*raw_byte_data |= char_to_xdigit(*buf);
+			raw_byte_data--;
+		}
 	}
 
 	ret = tegra_fuse_program(&data, BIT(param));
@@ -724,7 +724,7 @@ static ssize_t fuse_store(struct kobject *kobj, struct kobj_attribute *attr,
 
 	wake_unlock(&fuse_wk_lock);
 	wake_lock_destroy(&fuse_wk_lock);
-	return count;
+	return orig_count;
 }
 
 static ssize_t fuse_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)