NAND: DaVinci: V2 Adding 4 BIT ECC support
authorSandeep Paulraj <s-paulraj@ti.com>
Tue, 18 Aug 2009 14:10:42 +0000 (10:10 -0400)
committerScott Wood <scottwood@freescale.com>
Wed, 26 Aug 2009 20:37:03 +0000 (15:37 -0500)
This patch adds 4 BIT ECC support in the DaVinci NAND
driver. Tested on both the DM355 and DM365.

Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
drivers/mtd/nand/davinci_nand.c
include/asm-arm/arch-davinci/emif_defs.h

index 7837a8e3275239ce3053388b158fdc2ca4b00f3a..37d8b7312cf96d172b4132cb8b3f8db8ec5879b4 100644 (file)
 #include <asm/arch/nand_defs.h>
 #include <asm/arch/emif_defs.h>
 
+/* Definitions for 4-bit hardware ECC */
+#define NAND_TIMEOUT                   10240
+#define NAND_ECC_BUSY                  0xC
+#define NAND_4BITECC_MASK              0x03FF03FF
+#define EMIF_NANDFSR_ECC_STATE_MASK    0x00000F00
+#define ECC_STATE_NO_ERR               0x0
+#define ECC_STATE_TOO_MANY_ERRS                0x1
+#define ECC_STATE_ERR_CORR_COMP_P      0x2
+#define ECC_STATE_ERR_CORR_COMP_N      0x3
+
 static emif_registers *const emif_regs = (void *) DAVINCI_ASYNC_EMIF_CNTRL_BASE;
 
 static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
@@ -170,6 +180,268 @@ static int nand_davinci_correct_data(struct mtd_info *mtd, u_char *dat, u_char *
 }
 #endif /* CONFIG_SYS_NAND_HW_ECC */
 
+#ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
+static struct nand_ecclayout nand_davinci_4bit_layout_oobfirst = {
+/*
+ * TI uses a different layout for 4K page deviecs. Since the
+ * eccpos filed can hold only a limited number of entries, adding
+ * support for 4K page will result in compilation warnings
+ * 4K Support will be added later
+ */
+#ifdef CONFIG_SYS_NAND_PAGE_2K
+       .eccbytes = 40,
+       .eccpos = {
+               24, 25, 26, 27, 28,
+               29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
+               39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
+               49, 50, 51, 52, 53, 54, 55, 56, 57, 58,
+               59, 60, 61, 62, 63,
+               },
+       .oobfree = {
+               {.offset = 2, .length = 22, },
+       },
+#endif
+};
+#endif
+
+static void nand_davinci_4bit_enable_hwecc(struct mtd_info *mtd, int mode)
+{
+       u32 val;
+
+       switch (mode) {
+       case NAND_ECC_WRITE:
+       case NAND_ECC_READ:
+               /*
+                * Start a new ECC calculation for reading or writing 512 bytes
+                * of data.
+                */
+               val = (emif_regs->NANDFCR & ~(3 << 4)) | (1 << 12);
+               emif_regs->NANDFCR = val;
+               break;
+       case NAND_ECC_READSYN:
+               val = emif_regs->NAND4BITECC1;
+               break;
+       default:
+               break;
+       }
+}
+
+static u32 nand_davinci_4bit_readecc(struct mtd_info *mtd, unsigned int ecc[4])
+{
+       ecc[0] = emif_regs->NAND4BITECC1 & NAND_4BITECC_MASK;
+       ecc[1] = emif_regs->NAND4BITECC2 & NAND_4BITECC_MASK;
+       ecc[2] = emif_regs->NAND4BITECC3 & NAND_4BITECC_MASK;
+       ecc[3] = emif_regs->NAND4BITECC4 & NAND_4BITECC_MASK;
+
+       return 0;
+}
+
+static int nand_davinci_4bit_calculate_ecc(struct mtd_info *mtd,
+                                          const uint8_t *dat,
+                                          uint8_t *ecc_code)
+{
+       unsigned int hw_4ecc[4] = { 0, 0, 0, 0 };
+       unsigned int const1 = 0, const2 = 0;
+       unsigned char count1 = 0;
+
+       nand_davinci_4bit_readecc(mtd, hw_4ecc);
+
+       /*Convert 10 bit ecc value to 8 bit */
+       for (count1 = 0; count1 < 2; count1++) {
+               const2 = count1 * 5;
+               const1 = count1 * 2;
+
+               /* Take first 8 bits from val1 (count1=0) or val5 (count1=1) */
+               ecc_code[const2] = hw_4ecc[const1] & 0xFF;
+
+               /*
+                * Take 2 bits as LSB bits from val1 (count1=0) or val5
+                * (count1=1) and 6 bits from val2 (count1=0) or
+                * val5 (count1=1)
+                */
+               ecc_code[const2 + 1] =
+                   ((hw_4ecc[const1] >> 8) & 0x3) | ((hw_4ecc[const1] >> 14) &
+                                                     0xFC);
+
+               /*
+                * Take 4 bits from val2 (count1=0) or val5 (count1=1) and
+                * 4 bits from val3 (count1=0) or val6 (count1=1)
+                */
+               ecc_code[const2 + 2] =
+                   ((hw_4ecc[const1] >> 22) & 0xF) |
+                   ((hw_4ecc[const1 + 1] << 4) & 0xF0);
+
+               /*
+                * Take 6 bits from val3(count1=0) or val6 (count1=1) and
+                * 2 bits from val4 (count1=0) or  val7 (count1=1)
+                */
+               ecc_code[const2 + 3] =
+                   ((hw_4ecc[const1 + 1] >> 4) & 0x3F) |
+                   ((hw_4ecc[const1 + 1] >> 10) & 0xC0);
+
+               /* Take 8 bits from val4 (count1=0) or val7 (count1=1) */
+               ecc_code[const2 + 4] = (hw_4ecc[const1 + 1] >> 18) & 0xFF;
+       }
+       return 0;
+}
+
+
+static int nand_davinci_4bit_correct_data(struct mtd_info *mtd, uint8_t *dat,
+                                         uint8_t *read_ecc, uint8_t *calc_ecc)
+{
+       struct nand_chip *this = mtd->priv;
+       unsigned short ecc_10bit[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+       int i;
+       unsigned int hw_4ecc[4] = { 0, 0, 0, 0 }, iserror = 0;
+       unsigned short *pspare = NULL, *pspare1 = NULL;
+       unsigned int numerrors, erroraddress, errorvalue;
+       u32 val;
+
+       /*
+        * Check for an ECC where all bytes are 0xFF.  If this is the case, we
+        * will assume we are looking at an erased page and we should ignore
+        * the ECC.
+        */
+       for (i = 0; i < 10; i++) {
+               if (read_ecc[i] != 0xFF)
+                       break;
+       }
+       if (i == 10)
+               return 0;
+
+       /* Convert 8 bit in to 10 bit */
+       pspare = (unsigned short *)&read_ecc[2];
+       pspare1 = (unsigned short *)&read_ecc[0];
+
+       /* Take 10 bits from 0th and 1st bytes */
+       ecc_10bit[0] = (*pspare1) & 0x3FF;
+
+       /* Take 6 bits from 1st byte and 4 bits from 2nd byte */
+       ecc_10bit[1] = (((*pspare1) >> 10) & 0x3F)
+           | (((pspare[0]) << 6) & 0x3C0);
+
+       /* Take 4 bits form 2nd bytes and 6 bits from 3rd bytes */
+       ecc_10bit[2] = ((pspare[0]) >> 4) & 0x3FF;
+
+       /*Take 2 bits from 3rd byte and 8 bits from 4th byte */
+       ecc_10bit[3] = (((pspare[0]) >> 14) & 0x3)
+           | ((((pspare[1])) << 2) & 0x3FC);
+
+       /* Take 8 bits from 5th byte and 2 bits from 6th byte */
+       ecc_10bit[4] = ((pspare[1]) >> 8)
+           | ((((pspare[2])) << 8) & 0x300);
+
+       /* Take 6 bits from 6th byte and 4 bits from 7th byte */
+       ecc_10bit[5] = (pspare[2] >> 2) & 0x3FF;
+
+       /* Take 4 bits from 7th byte and 6 bits from 8th byte */
+       ecc_10bit[6] = (((pspare[2]) >> 12) & 0xF)
+           | ((((pspare[3])) << 4) & 0x3F0);
+
+       /*Take 2 bits from 8th byte and 8 bits from 9th byte */
+       ecc_10bit[7] = ((pspare[3]) >> 6) & 0x3FF;
+
+       /*
+        * Write the parity values in the NAND Flash 4-bit ECC Load register.
+        * Write each parity value one at a time starting from 4bit_ecc_val8
+        * to 4bit_ecc_val1.
+        */
+       for (i = 7; i >= 0; i--)
+               emif_regs->NAND4BITECCLOAD = ecc_10bit[i];
+
+       /*
+        * Perform a dummy read to the EMIF Revision Code and Status register.
+        * This is required to ensure time for syndrome calculation after
+        * writing the ECC values in previous step.
+        */
+
+       val = emif_regs->NANDFSR;
+
+       /*
+        * Read the syndrome from the NAND Flash 4-Bit ECC 1-4 registers.
+        * A syndrome value of 0 means no bit errors. If the syndrome is
+        * non-zero then go further otherwise return.
+        */
+       nand_davinci_4bit_readecc(mtd, hw_4ecc);
+
+       if (hw_4ecc[0] == ECC_STATE_NO_ERR && hw_4ecc[1] == ECC_STATE_NO_ERR &&
+           hw_4ecc[2] == ECC_STATE_NO_ERR && hw_4ecc[3] == ECC_STATE_NO_ERR)
+               return 0;
+
+       /*
+        * Clear any previous address calculation by doing a dummy read of an
+        * error address register.
+        */
+       val = emif_regs->NANDERRADD1;
+
+       /*
+        * Set the addr_calc_st bit(bit no 13) in the NAND Flash Control
+        * register to 1.
+        */
+       emif_regs->NANDFCR |= 1 << 13;
+
+       /*
+        * Wait for the corr_state field (bits 8 to 11)in the
+        * NAND Flash Status register to be equal to 0x0, 0x1, 0x2, or 0x3.
+        */
+       i = NAND_TIMEOUT;
+       do {
+               val = emif_regs->NANDFSR;
+               val &= 0xc00;
+               i--;
+       } while ((i > 0) && val);
+
+       iserror = emif_regs->NANDFSR;
+       iserror &= EMIF_NANDFSR_ECC_STATE_MASK;
+       iserror = iserror >> 8;
+
+       /*
+        * ECC_STATE_TOO_MANY_ERRS (0x1) means errors cannot be
+        * corrected (five or more errors).  The number of errors
+        * calculated (err_num field) differs from the number of errors
+        * searched.  ECC_STATE_ERR_CORR_COMP_P (0x2) means error
+        * correction complete (errors on bit 8 or 9).
+        * ECC_STATE_ERR_CORR_COMP_N (0x3) means error correction
+        * complete (error exists).
+        */
+
+       if (iserror == ECC_STATE_NO_ERR) {
+               val = emif_regs->NANDERRVAL1;
+               return 0;
+       } else if (iserror == ECC_STATE_TOO_MANY_ERRS) {
+               val = emif_regs->NANDERRVAL1;
+               return -1;
+       }
+
+       numerrors = ((emif_regs->NANDFSR >> 16) & 0x3) + 1;
+
+       /* Read the error address, error value and correct */
+       for (i = 0; i < numerrors; i++) {
+               if (i > 1) {
+                       erroraddress =
+                           ((emif_regs->NANDERRADD2 >>
+                             (16 * (i & 1))) & 0x3FF);
+                       erroraddress = ((512 + 7) - erroraddress);
+                       errorvalue =
+                           ((emif_regs->NANDERRVAL2 >>
+                             (16 * (i & 1))) & 0xFF);
+               } else {
+                       erroraddress =
+                           ((emif_regs->NANDERRADD1 >>
+                             (16 * (i & 1))) & 0x3FF);
+                       erroraddress = ((512 + 7) - erroraddress);
+                       errorvalue =
+                           ((emif_regs->NANDERRVAL1 >>
+                             (16 * (i & 1))) & 0xFF);
+               }
+               /* xor the corrupt data with error value */
+               if (erroraddress < 512)
+                       dat[erroraddress] ^= errorvalue;
+       }
+
+       return numerrors;
+}
+
 static int nand_davinci_dev_ready(struct mtd_info *mtd)
 {
        return emif_regs->NANDFSR & 0x1;
@@ -215,7 +487,7 @@ void davinci_nand_init(struct nand_chip *nand)
 {
        nand->chip_delay  = 0;
 #ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
-       nand->options     = NAND_USE_FLASH_BBT;
+       nand->options     |= NAND_USE_FLASH_BBT;
 #endif
 #ifdef CONFIG_SYS_NAND_HW_ECC
        nand->ecc.mode = NAND_ECC_HW;
@@ -227,7 +499,15 @@ void davinci_nand_init(struct nand_chip *nand)
 #else
        nand->ecc.mode = NAND_ECC_SOFT;
 #endif /* CONFIG_SYS_NAND_HW_ECC */
-
+#ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
+       nand->ecc.mode = NAND_ECC_HW_OOB_FIRST;
+       nand->ecc.size = 512;
+       nand->ecc.bytes = 10;
+       nand->ecc.calculate = nand_davinci_4bit_calculate_ecc;
+       nand->ecc.correct = nand_davinci_4bit_correct_data;
+       nand->ecc.hwctl = nand_davinci_4bit_enable_hwecc;
+       nand->ecc.layout = &nand_davinci_4bit_layout_oobfirst;
+#endif
        /* Set address of hardware control function */
        nand->cmd_ctrl = nand_davinci_hwcontrol;
 
index 646fc7746940dac5c25c3db4c3ba4b83df8f087c..c91e30c8fca2d57c39f33ab2f8412436f1cfec2c 100644 (file)
@@ -55,6 +55,16 @@ typedef struct {
        dv_reg          NANDF2ECC;
        dv_reg          NANDF3ECC;
        dv_reg          NANDF4ECC;
+       u_int8_t        RSVD2[60];
+       dv_reg          NAND4BITECCLOAD;
+       dv_reg          NAND4BITECC1;
+       dv_reg          NAND4BITECC2;
+       dv_reg          NAND4BITECC3;
+       dv_reg          NAND4BITECC4;
+       dv_reg          NANDERRADD1;
+       dv_reg          NANDERRADD2;
+       dv_reg          NANDERRVAL1;
+       dv_reg          NANDERRVAL2;
 } emif_registers;
 
 typedef emif_registers *emifregs;