[RFC PATCH 07/10] OMAP: GPMC: Introduce APIs for Configuring ECC Engine
From: Roger Quadros
Date: Wed Jul 09 2014 - 08:38:54 EST
Even though the ECC/BCH engine is meant for exclusive use by
the OMAP NAND controller, the ECC/BCH registers belong
to the GPMC controller's register space
Add omap_gpmc_ecc_configure_enable() and omap_gpmc_ecc_disable()
to manage the ECC engine. OMAP NAND driver must use these APIs
instead of directly accessing the ECC Engine registers.
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
arch/arm/mach-omap2/gpmc.c | 109 ++++++++++++++++++++++++++++++++++++-----
include/linux/omap-gpmc-nand.h | 25 ++++++++++
2 files changed, 121 insertions(+), 13 deletions(-)
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 43e2a9d..8befd16 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -73,19 +73,6 @@
#define GPMC_ECC_BCH_RESULT_5 0x304 /* not available on OMAP2 */
#define GPMC_ECC_BCH_RESULT_6 0x308 /* not available on OMAP2 */
-/* GPMC ECC control settings */
-#define GPMC_ECC_CTRL_ECCCLEAR 0x100
-#define GPMC_ECC_CTRL_ECCDISABLE 0x000
-#define GPMC_ECC_CTRL_ECCREG1 0x001
-#define GPMC_ECC_CTRL_ECCREG2 0x002
-#define GPMC_ECC_CTRL_ECCREG3 0x003
-#define GPMC_ECC_CTRL_ECCREG4 0x004
-#define GPMC_ECC_CTRL_ECCREG5 0x005
-#define GPMC_ECC_CTRL_ECCREG6 0x006
-#define GPMC_ECC_CTRL_ECCREG7 0x007
-#define GPMC_ECC_CTRL_ECCREG8 0x008
-#define GPMC_ECC_CTRL_ECCREG9 0x009
-
#define GPMC_CONFIG2_CSEXTRADELAY BIT(7)
#define GPMC_CONFIG3_ADVEXTRADELAY BIT(7)
#define GPMC_CONFIG4_OEEXTRADELAY BIT(7)
@@ -129,6 +116,28 @@
#define GPMC_PREFETCH_STATUS_COUNT(val) (val & 0x00003fff)
#define GPMC_PREFETCH_STATUS_FIFO_CNT(val) ((val >> 24) & 0x7F)
+/* GPMC ECC config */
+#define GPMC_ECC_CONFIG_ECCENABLE BIT(0)
+#define GPMC_ECC_CONFIG_ECCCS_MASK GENMASK(3, 1)
+#define GPMC_ECC_CONFIG_ECCCS_SHIFT 1
+#define GPMC_ECC_CONFIG_ECCNSECTOR_MASK GENMASK(6, 4)
+#define GPMC_ECC_CONFIG_ECCNSECTOR_SHIFT 4
+#define GPMC_ECC_CONFIG_ECC16B BIT(7)
+#define GPMC_ECC_CONFIG_ECCWRAPMODE_MASK GENMASK(11, 8)
+#define GPMC_ECC_CONFIG_ECCWRAPMODE_SHIFT 8
+#define GPMC_ECC_CONFIG_ECCBCHTSEL_MASK GENMASK(13, 12)
+#define GPMC_ECC_CONFIG_ECCBCHTSEL_SHIFT 12
+#define GPMC_ECC_CONFIG_ECCALGBCH BIT(16)
+
+/* GPMC ECC control */
+#define GPMC_ECC_CONTROL_ECCCLEAR BIT(8)
+#define GPMC_ECC_CONTROL_ECCPOINTER_MASK GENMASK(3, 0)
+#define GPMC_ECC_CONTROL_ECCPOINTER_SHIFT 0
+
+/* GPMC ECC size */
+#define GPMC_ECC_SIZE_ECCSIZE0_SHIFT 12
+#define GPMC_ECC_SIZE_ECCSIZE1_SHIFT 22
+
/* XXX: Only NAND irq has been considered,currently these are the only ones used
*/
#define GPMC_NR_IRQ 2
@@ -2105,3 +2114,77 @@ u32 omap_gpmc_get_prefetch_fifo_count(void)
count = GPMC_PREFETCH_STATUS_FIFO_CNT(count);
return count;
}
+
+/**
+ * omap_gpmc_ecc_disable - Disables the ECC engine
+ * but doesn't clear the ECC result registers.
+ */
+void omap_gpmc_ecc_disable(void)
+{
+ u32 val;
+
+ /* Disable ECC engine if running */
+ val = gpmc_read_reg(GPMC_ECC_CONFIG);
+ if (val & GPMC_ECC_CONFIG_ECCENABLE) {
+ val &= ~GPMC_ECC_CONFIG_ECCENABLE;
+ gpmc_write_reg(GPMC_ECC_CONFIG, val);
+ }
+}
+
+/**
+ * omap_gpmc_ecc_configure_enable - Configures and enables the ECC-BCH engine
+ *
+ * @cs: chip select number
+ * @ecc16: true for 16-bit ECC column, false for 8-bit ECC columna
+ * @ecc_size0: This value is written to ECCSIZE0 of GPMC_ECC_SIZE_CONFIG reg.
+ * @ecc_size1: This value is written to ECCSIZE1 of GPMC_ECC_SIZE_CONFIG reg.
+ * @use_bch: true for BCH algorithm, false for 1-bit Hamming code algorithm
+ * @bch_type: enum omap_gpmc_bch_type, 4-bit, 8-bit or 16-bit BCH error
+ * correction cabability. Ignored if use_bch is false.
+ * @bch_sectors: No. of sectors to process with BCH. Ignored if use_bch false.
+ * @bch_wrap_mode: pre defined spare area defination for BCH calculation.
+ * Ignored if use_bch is false
+ */
+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)
+{
+ u32 val, valx;
+
+ /* Disable ECC engine if running */
+ omap_gpmc_ecc_disable();
+
+ /* Clear all ECC/BCH result registers */
+ gpmc_write_reg(GPMC_ECC_CONTROL, GPMC_ECC_CONTROL_ECCCLEAR);
+
+ /* ECC size */
+ val = (ecc_size1 << GPMC_ECC_SIZE_ECCSIZE1_SHIFT) |
+ (ecc_size0 << GPMC_ECC_SIZE_ECCSIZE0_SHIFT);
+ gpmc_write_reg(GPMC_ECC_SIZE_CONFIG, val);
+
+ /* ECC config */
+ val = (cs << GPMC_ECC_CONFIG_ECCCS_SHIFT) & GPMC_ECC_CONFIG_ECCCS_MASK;
+
+ if (ecc16)
+ val |= GPMC_ECC_CONFIG_ECC16B;
+
+ if (use_bch) {
+ val |= GPMC_ECC_CONFIG_ECCALGBCH;
+ val |= (bch_type << GPMC_ECC_CONFIG_ECCBCHTSEL_SHIFT) &
+ GPMC_ECC_CONFIG_ECCBCHTSEL_MASK;
+ val |= (bch_sectors << GPMC_ECC_CONFIG_ECCNSECTOR_SHIFT) &
+ GPMC_ECC_CONFIG_ECCNSECTOR_MASK;
+ val |= (bch_wrap_mode << GPMC_ECC_CONFIG_ECCWRAPMODE_SHIFT) &
+ GPMC_ECC_CONFIG_ECCWRAPMODE_MASK;
+ } else {
+ /* Reset ECC result pointer to 1 */
+ valx = (1 << GPMC_ECC_CONTROL_ECCPOINTER_SHIFT) &
+ GPMC_ECC_CONTROL_ECCPOINTER_MASK;
+ gpmc_write_reg(GPMC_ECC_CONTROL, valx);
+ }
+
+ /* Enable ECC engine */
+ val |= GPMC_ECC_CONFIG_ECCENABLE;
+ gpmc_write_reg(GPMC_ECC_CONFIG, val);
+}
diff --git a/include/linux/omap-gpmc-nand.h b/include/linux/omap-gpmc-nand.h
index c445d89..f08cd05 100644
--- a/include/linux/omap-gpmc-nand.h
+++ b/include/linux/omap-gpmc-nand.h
@@ -23,6 +23,12 @@ enum omap_gpmc_reg {
OMAP_GPMC_NAND_DATA,
};
+enum omap_gpmc_bch_type {
+ OMAP_GPMC_BCH4,
+ OMAP_GPMC_BCH8,
+ OMAP_GPMC_BCH16,
+};
+
#ifdef CONFIG_ARCH_OMAP2PLUS
u32 omap_gpmc_read_reg(int cs, enum omap_gpmc_reg reg);
void omap_gpmc_write_reg(int cs, enum omap_gpmc_reg reg, u32 val);
@@ -32,6 +38,11 @@ int omap_gpmc_prefetch_start(int cs, int fifo_th, bool dma,
int omap_gpmc_prefetch_stop(int cs);
u32 omap_gpmc_get_prefetch_count(void);
u32 omap_gpmc_get_prefetch_fifo_count(void);
+void omap_gpmc_ecc_disable(void);
+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);
#else
static inline u32 omap_gpmc_read_reg(int cs, enum omap_gpmc_reg reg)
{
@@ -62,6 +73,20 @@ static inline u32 omap_gpmc_get_prefetch_fifo_count(void)
{
return 0;
}
+
+static inline void omap_gpmc_ecc_disable(void)
+{
+}
+
+static inline 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)
+{
+}
+
#endif
/* Prefetch/Write-post Engine */
--
1.8.3.2
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