mtd: nand: omap: make am33xx/elm.c as common driver for all OMAPx and AMxxxx platforms

ELM hardware engine which is used for ECC error detection, is present on all
latest OMAP SoC (like OMAP4xxx, OMAP5xxx, DRA7xxx, AM33xx, AM43xx). Thus ELM
driver should be moved to common drivers/mtd/nand/ folder so that all SoC
having on-chip ELM hardware engine can re-use it.
This patch has following changes:
- mv arch/arm/include/asm/arch-am33xx/elm.h arch/arm/include/asm/omap_elm.h
- mv arch/arm/cpu/armv7/am33xx/elm.c drivers/mtd/nand/omap_elm.c
- update Makefiles
- update #include <asm/elm.h>
- add CONFIG_NAND_OMAP_ELM to compile driver/mtd/nand/omap_elm.c
	and include in all board configs using AM33xx SoC platform.

Signed-off-by: Pekon Gupta <pekon@ti.com>

3 files changed, 198 insertions, 1 deletions

diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index eb1eafa..e145cd1 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_NAND_S3C2410) += s3c2410_nand.o
 obj-$(CONFIG_NAND_SPEAR) += spr_nand.o
 obj-$(CONFIG_TEGRA_NAND) += tegra_nand.o
 obj-$(CONFIG_NAND_OMAP_GPMC) += omap_gpmc.o
+obj-$(CONFIG_NAND_OMAP_ELM) += omap_elm.o
 obj-$(CONFIG_NAND_PLAT) += nand_plat.o
 obj-$(CONFIG_NAND_DOCG4) += docg4.o
 
diff --git a/drivers/mtd/nand/omap_elm.c b/drivers/mtd/nand/omap_elm.c
new file mode 100644
index 0000000..2aa7807
--- /dev/null
+++ b/drivers/mtd/nand/omap_elm.c
@@ -0,0 +1,196 @@
+/*
+ * (C) Copyright 2010-2011 Texas Instruments, <www.ti.com>
+ * Mansoor Ahamed <mansoor.ahamed@ti.com>
+ *
+ * BCH Error Location Module (ELM) support.
+ *
+ * NOTE:
+ * 1. Supports only continuous mode. Dont see need for page mode in uboot
+ * 2. Supports only syndrome polynomial 0. i.e. poly local variable is
+ *    always set to ELM_DEFAULT_POLY. Dont see need for other polynomial
+ *    sets in uboot
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/errno.h>
+#include <asm/arch/cpu.h>
+#include <asm/omap_gpmc.h>
+#include <asm/omap_elm.h>
+
+#define ELM_DEFAULT_POLY (0)
+
+struct elm *elm_cfg;
+
+/**
+ * elm_load_syndromes - Load BCH syndromes based on nibble selection
+ * @syndrome: BCH syndrome
+ * @nibbles:
+ * @poly: Syndrome Polynomial set to use
+ *
+ * Load BCH syndromes based on nibble selection
+ */
+static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
+{
+	u32 *ptr;
+	u32 val;
+
+	/* reg 0 */
+	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[0];
+	val = syndrome[0] | (syndrome[1] << 8) | (syndrome[2] << 16) |
+				(syndrome[3] << 24);
+	writel(val, ptr);
+	/* reg 1 */
+	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[1];
+	val = syndrome[4] | (syndrome[5] << 8) | (syndrome[6] << 16) |
+				(syndrome[7] << 24);
+	writel(val, ptr);
+
+	/* BCH 8-bit with 26 nibbles (4*8=32) */
+	if (nibbles > 13) {
+		/* reg 2 */
+		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[2];
+		val = syndrome[8] | (syndrome[9] << 8) | (syndrome[10] << 16) |
+				(syndrome[11] << 24);
+		writel(val, ptr);
+		/* reg 3 */
+		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[3];
+		val = syndrome[12] | (syndrome[13] << 8) |
+			(syndrome[14] << 16) | (syndrome[15] << 24);
+		writel(val, ptr);
+	}
+
+	/* BCH 16-bit with 52 nibbles (7*8=56) */
+	if (nibbles > 26) {
+		/* reg 4 */
+		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[4];
+		val = syndrome[16] | (syndrome[17] << 8) |
+			(syndrome[18] << 16) | (syndrome[19] << 24);
+		writel(val, ptr);
+
+		/* reg 5 */
+		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[5];
+		val = syndrome[20] | (syndrome[21] << 8) |
+			(syndrome[22] << 16) | (syndrome[23] << 24);
+		writel(val, ptr);
+
+		/* reg 6 */
+		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6];
+		val = syndrome[24] | (syndrome[25] << 8) |
+			(syndrome[26] << 16) | (syndrome[27] << 24);
+		writel(val, ptr);
+	}
+}
+
+/**
+ * elm_check_errors - Check for BCH errors and return error locations
+ * @syndrome: BCH syndrome
+ * @nibbles:
+ * @error_count: Returns number of errrors in the syndrome
+ * @error_locations: Returns error locations (in decimal) in this array
+ *
+ * Check the provided syndrome for BCH errors and return error count
+ * and locations in the array passed. Returns -1 if error is not correctable,
+ * else returns 0
+ */
+int elm_check_error(u8 *syndrome, u32 nibbles, u32 *error_count,
+		u32 *error_locations)
+{
+	u8 poly = ELM_DEFAULT_POLY;
+	s8 i;
+	u32 location_status;
+
+	elm_load_syndromes(syndrome, nibbles, poly);
+
+	/* start processing */
+	writel((readl(&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6])
+				| ELM_SYNDROME_FRAGMENT_6_SYNDROME_VALID),
+		&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6]);
+
+	/* wait for processing to complete */
+	while ((readl(&elm_cfg->irqstatus) & (0x1 << poly)) != 0x1)
+		;
+	/* clear status */
+	writel((readl(&elm_cfg->irqstatus) | (0x1 << poly)),
+			&elm_cfg->irqstatus);
+
+	/* check if correctable */
+	location_status = readl(&elm_cfg->error_location[poly].location_status);
+	if (!(location_status & ELM_LOCATION_STATUS_ECC_CORRECTABLE_MASK))
+		return -1;
+
+	/* get error count */
+	*error_count = readl(&elm_cfg->error_location[poly].location_status) &
+					ELM_LOCATION_STATUS_ECC_NB_ERRORS_MASK;
+
+	for (i = 0; i < *error_count; i++) {
+		error_locations[i] =
+		     readl(&elm_cfg->error_location[poly].error_location_x[i]);
+	}
+
+	return 0;
+}
+
+
+/**
+ * elm_config - Configure ELM module
+ * @level: 4 / 8 / 16 bit BCH
+ *
+ * Configure ELM module based on BCH level.
+ * Set mode as continuous mode.
+ * Currently we are using only syndrome 0 and syndromes 1 to 6 are not used.
+ * Also, the mode is set only for syndrome 0
+ */
+int elm_config(enum bch_level level)
+{
+	u32 val;
+	u8 poly = ELM_DEFAULT_POLY;
+	u32 buffer_size = 0x7FF;
+
+	/* config size and level */
+	val = (u32)(level) & ELM_LOCATION_CONFIG_ECC_BCH_LEVEL_MASK;
+	val |= ((buffer_size << ELM_LOCATION_CONFIG_ECC_SIZE_POS) &
+				ELM_LOCATION_CONFIG_ECC_SIZE_MASK);
+	writel(val, &elm_cfg->location_config);
+
+	/* config continous mode */
+	/* enable interrupt generation for syndrome polynomial set */
+	writel((readl(&elm_cfg->irqenable) | (0x1 << poly)),
+			&elm_cfg->irqenable);
+	/* set continuous mode for the syndrome polynomial set */
+	writel((readl(&elm_cfg->page_ctrl) & ~(0x1 << poly)),
+			&elm_cfg->page_ctrl);
+
+	return 0;
+}
+
+/**
+ * elm_reset - Do a soft reset of ELM
+ *
+ * Perform a soft reset of ELM and return after reset is done.
+ */
+void elm_reset(void)
+{
+	/* initiate reset */
+	writel((readl(&elm_cfg->sysconfig) | ELM_SYSCONFIG_SOFTRESET),
+			&elm_cfg->sysconfig);
+
+	/* wait for reset complete and normal operation */
+	while ((readl(&elm_cfg->sysstatus) & ELM_SYSSTATUS_RESETDONE) !=
+		ELM_SYSSTATUS_RESETDONE)
+		;
+}
+
+/**
+ * elm_init - Initialize ELM module
+ *
+ * Initialize ELM support. Currently it does only base address init
+ * and ELM reset.
+ */
+void elm_init(void)
+{
+	elm_cfg = (struct elm *)ELM_BASE;
+	elm_reset();
+}
diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index ec1787f..c828859 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -16,7 +16,7 @@
 #include <linux/compiler.h>
 #include <nand.h>
 #ifdef CONFIG_AM33XX
-#include <asm/arch/elm.h>
+#include <asm/omap_elm.h>
 #endif
 
 static uint8_t cs;