[RFC PATCH 08/10] OMAP: GPMC: Introduce APIs to get ECC/BCH results

From: Roger Quadros
Date: Wed Jul 09 2014 - 08:39:12 EST

Even though the ECC/BCH engine is meant for exclusive use by
the OMAP NAND controller, the ECC/BCH result registers belong
to the GPMC controller's register space.

Introduce 2 APIs to access the ECC/BCH results.
void omap_gpmc_ecc_get_result(int length, u32 *result);
void omap_gpmc_ecc_get_bch_result(int length, u8 sector, u32 *result);

The first one is to get the Hamming code ECC result registers
and the second one is to get the BCH ECC result registers.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
arch/arm/mach-omap2/gpmc.c | 97 +++++++++++++++++++++++++++++++++++++++---
include/linux/omap-gpmc-nand.h | 11 +++++
2 files changed, 101 insertions(+), 7 deletions(-)

diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 8befd16..9222244 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -65,6 +65,7 @@
#define GPMC_ECC_CONTROL 0x1f8
#define GPMC_ECC_SIZE_CONFIG 0x1fc
#define GPMC_ECC1_RESULT 0x200
+#define GPMC_ECC9_RESULT 0x220
#define GPMC_ECC_BCH_RESULT_0 0x240 /* not available on OMAP2 */
#define GPMC_ECC_BCH_RESULT_1 0x244 /* not available on OMAP2 */
#define GPMC_ECC_BCH_RESULT_2 0x248 /* not available on OMAP2 */
@@ -83,6 +84,7 @@
#define GPMC_CS0_OFFSET 0x60
#define GPMC_CS_SIZE 0x30
#define GPMC_BCH_SIZE 0x10
+#define GPMC_BCH_NUM 7 /* Max no. of BCH registers 0-6 */

#define GPMC_MEM_END 0x3FFFFFFF

@@ -96,9 +98,10 @@
#define GPMC_REVISION_MAJOR(l) ((l >> 4) & 0xf)
#define GPMC_REVISION_MINOR(l) (l & 0xf)

-#define GPMC_HAS_WR_ACCESS 0x1
-#define GPMC_HAS_WR_DATA_MUX_BUS 0x2
-#define GPMC_HAS_MUX_AAD 0x4
+#define GPMC_HAS_WR_ACCESS BIT(0)
+#define GPMC_HAS_WR_DATA_MUX_BUS BIT(1)
+#define GPMC_HAS_MUX_AAD BIT(2)
+#define GPMC_HAS_BCH BIT(3)

#define GPMC_NR_WAITPINS 4

@@ -185,6 +188,7 @@ static DEFINE_SPINLOCK(gpmc_mem_lock);
static unsigned int gpmc_cs_map = ((1 << GPMC_CS_NUM) - 1);
static unsigned int gpmc_cs_num = GPMC_CS_NUM;
static unsigned int gpmc_nr_waitpins;
+static unsigned int gpmc_bch_num = GPMC_BCH_NUM;
static struct device *gpmc_dev;
static int gpmc_irq;
static resource_size_t phys_base, mem_size;
@@ -198,6 +202,7 @@ struct gpmc_nand_reg {
};

static struct gpmc_nand_reg gpmc_nand_reg_map[GPMC_CS_NUM];
+void __iomem *gpmc_bch_reg_map[GPMC_BCH_NUM][GPMC_BCH_NUM_REMAINDER];

static struct clk *gpmc_l3_clk;

@@ -205,7 +210,7 @@ static irqreturn_t gpmc_handle_irq(int irq, void *dev);

static void gpmc_fill_nand_reg_map(void)
{
- int i;
+ int i, j;

for (i = 0; i < gpmc_cs_num; i++) {
gpmc_nand_reg_map[i].command = gpmc_base + GPMC_CS0_OFFSET +
@@ -215,6 +220,28 @@ static void gpmc_fill_nand_reg_map(void)
gpmc_nand_reg_map[i].data = gpmc_base + GPMC_CS0_OFFSET +
GPMC_CS_NAND_DATA + GPMC_CS_SIZE * i;
}
+
+ if (!(gpmc_capability & GPMC_HAS_BCH))
+ return;
+
+
+ for (i = 0; i < 4; i++) {
+ for (j = 0; j < 8; j++) {
+ gpmc_bch_reg_map[i][j] = gpmc_base +
+ GPMC_ECC_BCH_RESULT_0 +
+ i * 4 + GPMC_BCH_SIZE * j;
+ }
+ }
+
+ /* 2nd for loop for BCH4 onwards due to non-consecutive address */
+ for (i = 4; i < gpmc_bch_num; i++) {
+ for (j = 0; j < 8; j++) {
+ gpmc_bch_reg_map[i][j] = gpmc_base +
+ GPMC_ECC_BCH_RESULT_4 +
+ (i - 4) * 4 +
+ GPMC_BCH_SIZE * j;
+ }
+ }
}

static void gpmc_write_reg(int idx, u32 val)
@@ -1738,10 +1765,17 @@ static int gpmc_probe(struct platform_device *pdev)
* - OMAP3xxx = 5.0
* - OMAP44xx/54xx/AM335x = 6.0
*/
- if (GPMC_REVISION_MAJOR(l) > 0x4)
- gpmc_capability = GPMC_HAS_WR_ACCESS | GPMC_HAS_WR_DATA_MUX_BUS;
- if (GPMC_REVISION_MAJOR(l) > 0x5)
+ if (GPMC_REVISION_MAJOR(l) >= 5) {
+ gpmc_capability = GPMC_HAS_WR_ACCESS |
+ GPMC_HAS_WR_DATA_MUX_BUS | GPMC_HAS_BCH;
+ gpmc_bch_num = 4;
+ }
+
+ if (GPMC_REVISION_MAJOR(l) >= 6) {
gpmc_capability |= GPMC_HAS_MUX_AAD;
+ gpmc_bch_num = GPMC_BCH_NUM;
+ }
+
dev_info(gpmc_dev, "GPMC revision %d.%d\n", GPMC_REVISION_MAJOR(l),
GPMC_REVISION_MINOR(l));

@@ -2188,3 +2222,52 @@ void omap_gpmc_ecc_configure_enable(int cs, bool ecc16, u8 ecc_size0,
val |= GPMC_ECC_CONFIG_ECCENABLE;
gpmc_write_reg(GPMC_ECC_CONFIG, val);
}
+
+/**
+ * omap_gpmc_ecc_get_result - reads out the Hamming code ECC result registers
+ *
+ * @length: Number of 32-bit registers to read
+ * @result: pointer to 32-bit buffer where results should be copied into
+ */
+void omap_gpmc_ecc_get_result(int length, u32 *result)
+{
+ u32 reg_addr;
+ int i;
+
+ if (!gpmc_dev)
+ return;
+
+ reg_addr = GPMC_ECC1_RESULT;
+ for (i = 0; i < length; i++) {
+ *result++ = gpmc_read_reg(reg_addr);
+ reg_addr += 4;
+ /* Don't read past ECC_RESULT region */
+ if (reg_addr > GPMC_ECC9_RESULT)
+ break;
+ }
+}
+
+/**
+ * omap_gpmc_ecc_get_bch_result - reads out the BCH result registers
+ *
+ * @length: Number of 32-bit registers to read
+ * @sector: Which sector's results to read (0 to 7)
+ * @result: pointer to 32-bit buffer where results should be copied into
+ */
+void omap_gpmc_ecc_get_bch_result(int length, u8 sector, u32 *result)
+{
+ int i;
+
+ if (!gpmc_dev)
+ return;
+
+ if (sector > GPMC_BCH_NUM_REMAINDER)
+ return;
+
+ /* Don't read past BCH_RESULT region */
+ if (length > gpmc_bch_num)
+ length = gpmc_bch_num;
+
+ for (i = 0; i < length; i++)
+ *result++ = readl_relaxed(gpmc_bch_reg_map[i][sector]);
+}
diff --git a/include/linux/omap-gpmc-nand.h b/include/linux/omap-gpmc-nand.h
index f08cd05..d0ef165 100644
--- a/include/linux/omap-gpmc-nand.h
+++ b/include/linux/omap-gpmc-nand.h
@@ -43,6 +43,8 @@ void omap_gpmc_ecc_configure_enable(int cs, bool ecc16, u8 ecc_size0,
u8 ecc_size1, bool use_bch,
enum omap_gpmc_bch_type bch_type,
u8 bch_sectors, u8 bch_wrap_mode);
+void omap_gpmc_ecc_get_result(int length, u32 *result);
+void omap_gpmc_ecc_get_bch_result(int length, u8 sector, u32 *result);
#else
static inline u32 omap_gpmc_read_reg(int cs, enum omap_gpmc_reg reg)
{
@@ -87,6 +89,15 @@ static inline void omap_gpmc_ecc_configure_enable(int cs, bool ecc16,
{
}

+static inline void omap_gpmc_ecc_get_result(int length, u32 *result)
+{
+}
+
+static inline void omap_gpmc_ecc_get_bch_result(int length, u8 sector,
+ u32 *result)
+{
+}
+
#endif

/* Prefetch/Write-post Engine */
--
1.8.3.2

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