RE: [RFC PATCH 07/10] OMAP: GPMC: Introduce APIs for Configuring ECC Engine

2014-07-11 Thread Gupta, Pekon
Hi Roger,

From: Quadros, Roger

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 rog...@ti.com
---
As suggested in 
http://lists.infradead.org/pipermail/linux-mtd/2014-July/054595.html

Please try to move chip-ecc.calculate() implementations like
- omap_calculate_ecc_bch()
- omap_calculate_ecc()

From NAND driver To GPMC driver, as that should be easy, And solve
most of your work (no need to export GPMC registers).
- You may rename them appropriately and change the argument list
   if needed.
- And NAND driver can just have some wrapper functions to match
  the MTD interface arguments.


with regards, pekon



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[RFC PATCH 07/10] OMAP: GPMC: Introduce APIs for Configuring ECC Engine

2014-07-09 Thread Roger Quadros
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 rog...@ti.com
---
 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 @@
 #defineGPMC_ECC_BCH_RESULT_5   0x304   /* not available on OMAP2 */
 #defineGPMC_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
-
 #defineGPMC_CONFIG2_CSEXTRADELAY   BIT(7)
 #defineGPMC_CONFIG3_ADVEXTRADELAY  BIT(7)
 #defineGPMC_CONFIG4_OEEXTRADELAY   BIT(7)
@@ -129,6 +116,28 @@
 #define GPMC_PREFETCH_STATUS_COUNT(val)(val  0x3fff)
 #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_SHIFT1
+#define GPMC_ECC_CONFIG_ECCNSECTOR_MASKGENMASK(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_MASKGENMASK(13, 12)
+#define GPMC_ECC_CONFIG_ECCBCHTSEL_SHIFT   12
+#define GPMC_ECC_CONFIG_ECCALGBCH  BIT(16)
+
+/* GPMC ECC control */
+#defineGPMC_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
  */
 #defineGPMC_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