[U-Boot] [PATCH v1 1/4] mtd: nand: omap: enable BCH ECC scheme using ELM for generic platform

Pekon Gupta pekon at ti.com
Tue Aug 6 11:55:17 CEST 2013


BCH8_ECC scheme implemented in omap_gpmc.c driver has following two favours
+-----------------------------------+-----------------+-----------------+
|ECC Scheme                         | ECC Calculation | Error Detection |
+-----------------------------------+-----------------+-----------------+
|OMAP_ECC_BCH8_CODE_HW              |GPMC             |ELM H/W engine   |
|OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |GPMC             |S/W BCH library  |
+-----------------------------------+-----------------+-----------------+

Current implementation enables of BCH8_CODE_HW only for AM33xx SoC family.
(using CONFIG_AM33XX). However, other SoC families (like TI81xx) also have
ELM hardware module, and can support ECC error detection using ELM.

This patch
- replaces CONFIG_AM33xx define with generic CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW
  so that all device families having required h/w capability can use ELM for
  error detection in ECC_BCHx schemes.

- replaces CONFIG_NAND_OMAP_BCH8 with CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
  and separates out code for above mentioned BCH8_ECC implementations so that
  driver can be build independently using anyone of them.

Signed-off-by: Pekon Gupta <pekon at ti.com>
---
 drivers/mtd/nand/omap_gpmc.c | 117 +++++++++++++++++++++++--------------------
 include/configs/am335x_evm.h |   1 +
 include/configs/ti814x_evm.h |   2 +-
 include/configs/tricorder.h  |   2 +-
 4 files changed, 65 insertions(+), 57 deletions(-)

diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index ec1787f..c6c5cec 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -12,11 +12,12 @@
 #include <asm/arch/cpu.h>
 #include <asm/omap_gpmc.h>
 #include <linux/mtd/nand_ecc.h>
-#include <linux/bch.h>
 #include <linux/compiler.h>
 #include <nand.h>
-#ifdef CONFIG_AM33XX
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
 #include <asm/arch/elm.h>
+#elif defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW)
+#include <linux/bch.h>
 #endif
 
 static uint8_t cs;
@@ -274,7 +275,7 @@ static void omap_hwecc_init_bch(struct nand_chip *chip, int32_t mode)
 {
 	uint32_t val;
 	uint32_t dev_width = (chip->options & NAND_BUSWIDTH_16) >> 1;
-#ifdef CONFIG_AM33XX
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
 	uint32_t unused_length = 0;
 #endif
 	uint32_t wr_mode = BCH_WRAPMODE_6;
@@ -283,7 +284,7 @@ static void omap_hwecc_init_bch(struct nand_chip *chip, int32_t mode)
 	/* Clear the ecc result registers, select ecc reg as 1 */
 	writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
 
-#ifdef CONFIG_AM33XX
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
 	wr_mode = BCH_WRAPMODE_1;
 
 	switch (bch->nibbles) {
@@ -375,10 +376,10 @@ static void __maybe_unused omap_ecc_disable(struct mtd_info *mtd)
 	writel((readl(&gpmc_cfg->ecc_config) & ~0x1), &gpmc_cfg->ecc_config);
 }
 
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
 /*
  * BCH8 support (needs ELM and thus AM33xx-only)
  */
-#ifdef CONFIG_AM33XX
 /*
  * omap_read_bch8_result - Read BCH result for BCH8 level
  *
@@ -631,12 +632,12 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
 	}
 	return 0;
 }
-#endif /* CONFIG_AM33XX */
+#endif /* CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW */
 
 /*
  * OMAP3 BCH8 support (with BCH library)
  */
-#ifdef CONFIG_NAND_OMAP_BCH8
+#ifdef CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
 /*
  *  omap_calculate_ecc_bch - Read BCH ECC result
  *
@@ -752,7 +753,7 @@ static void __maybe_unused omap_free_bch(struct mtd_info *mtd)
 		chip_priv->control = NULL;
 	}
 }
-#endif /* CONFIG_NAND_OMAP_BCH8 */
+#endif /* CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW */
 
 #ifndef CONFIG_SPL_BUILD
 /*
@@ -803,25 +804,32 @@ void omap_nand_switch_ecc(uint32_t hardware, uint32_t eccstrength)
 			nand->ecc.calculate = omap_calculate_ecc;
 			omap_hwecc_init(nand);
 			printf("1-bit hamming HW ECC selected\n");
-		}
-#if defined(CONFIG_AM33XX) || defined(CONFIG_NAND_OMAP_BCH8)
-		else if (eccstrength == 8) {
-			nand->ecc.mode = NAND_ECC_HW;
-			nand->ecc.layout = &hw_bch8_nand_oob;
-			nand->ecc.size = 512;
-#ifdef CONFIG_AM33XX
-			nand->ecc.bytes = 14;
-			nand->ecc.read_page = omap_read_page_bch;
+		} else if (eccstrength == 8) {
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
+			nand->ecc.mode		= NAND_ECC_HW;
+			nand->ecc.layout	= &hw_bch8_nand_oob;
+			nand->ecc.size		= 512;
+			nand->ecc.bytes		= 14;
+			nand->ecc.read_page	= omap_read_page_bch;
+			nand->ecc.hwctl		= omap_enable_ecc_bch;
+			nand->ecc.correct	= omap_correct_data_bch;
+			nand->ecc.calculate	= omap_calculate_ecc_bch;
+			omap_hwecc_init_bch(nand, NAND_ECC_READ);
+			printf("using OMAP_ECC_BCH8_CODE_HW\n");
+#elif defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW)
+			nand->ecc.mode		= NAND_ECC_HW;
+			nand->ecc.layout	= &hw_bch8_nand_oob;
+			nand->ecc.size		= 512;
+			nand->ecc.bytes		= 13;
+			nand->ecc.hwctl		= omap_enable_ecc_bch;
+			nand->ecc.correct	= omap_correct_data_bch;
+			nand->ecc.calculate	= omap_calculate_ecc_bch;
+			omap_hwecc_init_bch(nand, NAND_ECC_READ);
+			printf("using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
 #else
-			nand->ecc.bytes = 13;
+			printf("selected ECC not supported or not enabled\n");
 #endif
-			nand->ecc.hwctl = omap_enable_ecc_bch;
-			nand->ecc.correct = omap_correct_data_bch;
-			nand->ecc.calculate = omap_calculate_ecc_bch;
-			omap_hwecc_init_bch(nand, NAND_ECC_READ);
-			printf("8-bit BCH HW ECC selected\n");
 		}
-#endif
 	} else {
 		nand->ecc.mode = NAND_ECC_SOFT;
 		/* Use mtd default settings */
@@ -894,44 +902,44 @@ int board_nand_init(struct nand_chip *nand)
 
 	nand->chip_delay = 100;
 
-#if defined(CONFIG_AM33XX) || defined(CONFIG_NAND_OMAP_BCH8)
-#ifdef CONFIG_AM33XX
-	/* AM33xx uses the ELM */
-	/* required in case of BCH */
+#if defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW)
+	printf("nand: using OMAP_ECC_BCH8_CODE_HW\n");
+	nand->ecc.mode		= NAND_ECC_HW;
+	nand->ecc.layout	= &hw_bch8_nand_oob;
+	nand->ecc.size		= CONFIG_SYS_NAND_ECCSIZE;
+	nand->ecc.bytes		= CONFIG_SYS_NAND_ECCBYTES;
+	nand->ecc.strength	= 8;
+	nand->ecc.hwctl		= omap_enable_ecc_bch;
+	nand->ecc.correct	= omap_correct_data_bch;
+	nand->ecc.calculate	= omap_calculate_ecc_bch;
+	nand->ecc.read_page	= omap_read_page_bch;
+	omap_hwecc_init_bch(nand, NAND_ECC_READ);
+	/* ELM is used for ECC error detection */
 	elm_init();
-#else
-	/*
-	 * Whereas other OMAP based SoC do not have the ELM, they use the BCH
-	 * SW library.
-	 */
-	bch_priv.control = init_bch(13, 8, 0x201b /* hw polynominal */);
+	nand->priv = &bch_priv;
+#elif defined(CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW)
+	printf("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
+	nand->ecc.mode		= NAND_ECC_HW;
+	nand->ecc.layout	= &hw_bch8_nand_oob;
+	nand->ecc.size		= CONFIG_SYS_NAND_ECCSIZE;
+	nand->ecc.bytes		= CONFIG_SYS_NAND_ECCBYTES;
+	nand->ecc.strength	= 8;
+	nand->ecc.hwctl		= omap_enable_ecc_bch;
+	nand->ecc.correct	= omap_correct_data_bch;
+	nand->ecc.calculate	= omap_calculate_ecc_bch;
+	omap_hwecc_init_bch(nand, NAND_ECC_READ);
+	/* BCH SW library is used for error detection */
+	bch_priv.control	= init_bch(13, 8, 0x201b /* hw polynominal */);
 	if (!bch_priv.control) {
 		puts("Could not init_bch()\n");
 		return -ENODEV;
 	}
-#endif
-	/* BCH info that will be correct for SPL or overridden otherwise. */
 	nand->priv = &bch_priv;
-#endif
-
-	/* Default ECC mode */
-#if defined(CONFIG_AM33XX) || defined(CONFIG_NAND_OMAP_BCH8)
-	nand->ecc.mode = NAND_ECC_HW;
-	nand->ecc.layout = &hw_bch8_nand_oob;
-	nand->ecc.size = CONFIG_SYS_NAND_ECCSIZE;
-	nand->ecc.bytes = CONFIG_SYS_NAND_ECCBYTES;
-	nand->ecc.strength = 8;
-	nand->ecc.hwctl = omap_enable_ecc_bch;
-	nand->ecc.correct = omap_correct_data_bch;
-	nand->ecc.calculate = omap_calculate_ecc_bch;
-#ifdef CONFIG_AM33XX
-	nand->ecc.read_page = omap_read_page_bch;
-#endif
-	omap_hwecc_init_bch(nand, NAND_ECC_READ);
-#else
-#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_NAND_SOFTECC)
+#elif !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_NAND_SOFTECC)
+	printf("nand: using OMAP_ECC_HAM1_CODE_SW\n");
 	nand->ecc.mode = NAND_ECC_SOFT;
 #else
+	printf("nand: using OMAP_ECC_HAM1_CODE_HW\n");
 	nand->ecc.mode = NAND_ECC_HW;
 	nand->ecc.layout = &hw_nand_oob;
 	nand->ecc.size = CONFIG_SYS_NAND_ECCSIZE;
@@ -942,7 +950,6 @@ int board_nand_init(struct nand_chip *nand)
 	nand->ecc.strength = 1;
 	omap_hwecc_init(nand);
 #endif
-#endif
 
 #ifdef CONFIG_SPL_BUILD
 	if (nand->options & NAND_BUSWIDTH_16)
diff --git a/include/configs/am335x_evm.h b/include/configs/am335x_evm.h
index c5a6d4b..8f3bd54 100644
--- a/include/configs/am335x_evm.h
+++ b/include/configs/am335x_evm.h
@@ -493,6 +493,7 @@
 #define CONFIG_NAND
 /* NAND support */
 #ifdef CONFIG_NAND
+#define CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW
 #define CONFIG_CMD_NAND
 #define CONFIG_CMD_MTDPARTS
 #define MTDIDS_DEFAULT			"nand0=omap2-nand.0"
diff --git a/include/configs/ti814x_evm.h b/include/configs/ti814x_evm.h
index b6fafc7..546cc07 100644
--- a/include/configs/ti814x_evm.h
+++ b/include/configs/ti814x_evm.h
@@ -286,7 +286,7 @@
 #define CONFIG_NAND
 /* NAND support */
 #ifdef CONFIG_NAND
-#define CONFIG_MTD_NAND_OMAP_BCH
+#define CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW
 #define CONFIG_CMD_NAND
 #define CONFIG_CMD_MTDPARTS
 #define MTDIDS_DEFAULT			"nand0=omap2-nand.0"
diff --git a/include/configs/tricorder.h b/include/configs/tricorder.h
index 4e2cb65..dc4f6dc 100644
--- a/include/configs/tricorder.h
+++ b/include/configs/tricorder.h
@@ -109,7 +109,7 @@
 
 #define CONFIG_SYS_MAX_NAND_DEVICE	1		/* Max number of NAND */
 							/* devices */
-#define CONFIG_NAND_OMAP_BCH8
+#define CONFIG_NAND_OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
 #define CONFIG_BCH
 
 /* commands to include */
-- 
1.8.1



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