mtd: add bcmring nand driver

Signed-off-by: Leo Hao Chen <leochen@broadcom.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/nand_bcm_umi.c

@@ -0,0 +1,149 @@
+/*****************************************************************************
+* Copyright 2004 - 2009 Broadcom Corporation.  All rights reserved.
+*
+* Unless you and Broadcom execute a separate written software license
+* agreement governing use of this software, this software is licensed to you
+* under the terms of the GNU General Public License version 2, available at
+* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+*
+* Notwithstanding the above, under no circumstances may you combine this
+* software in any way with any other Broadcom software provided under a
+* license other than the GPL, without Broadcom's express prior written
+* consent.
+*****************************************************************************/
+
+/* ---- Include Files ---------------------------------------------------- */
+#include <mach/reg_umi.h>
+#include "nand_bcm_umi.h"
+#ifdef BOOT0_BUILD
+#include <uart.h>
+#endif
+
+/* ---- External Variable Declarations ----------------------------------- */
+/* ---- External Function Prototypes ------------------------------------- */
+/* ---- Public Variables ------------------------------------------------- */
+/* ---- Private Constants and Types -------------------------------------- */
+/* ---- Private Function Prototypes -------------------------------------- */
+/* ---- Private Variables ------------------------------------------------ */
+/* ---- Private Functions ------------------------------------------------ */
+
+#if NAND_ECC_BCH
+/****************************************************************************
+*  nand_bch_ecc_flip_bit - Routine to flip an errored bit
+*
+*  PURPOSE:
+*     This is a helper routine that flips the bit (0 -> 1 or 1 -> 0) of the
+*     errored bit specified
+*
+*  PARAMETERS:
+*     datap - Container that holds the 512 byte data
+*     errorLocation - Location of the bit that needs to be flipped
+*
+*  RETURNS:
+*     None
+****************************************************************************/
+static void nand_bcm_umi_bch_ecc_flip_bit(uint8_t *datap, int errorLocation)
+{
+	int locWithinAByte = (errorLocation & REG_UMI_BCH_ERR_LOC_BYTE) >> 0;
+	int locWithinAWord = (errorLocation & REG_UMI_BCH_ERR_LOC_WORD) >> 3;
+	int locWithinAPage = (errorLocation & REG_UMI_BCH_ERR_LOC_PAGE) >> 5;
+
+	uint8_t errorByte = 0;
+	uint8_t byteMask = 1 << locWithinAByte;
+
+	/* BCH uses big endian, need to change the location
+	 * bits to little endian */
+	locWithinAWord = 3 - locWithinAWord;
+
+	errorByte = datap[locWithinAPage * sizeof(uint32_t) + locWithinAWord];
+
+#ifdef BOOT0_BUILD
+	puthexs("\nECC Correct Offset: ",
+		locWithinAPage * sizeof(uint32_t) + locWithinAWord);
+	puthexs(" errorByte:", errorByte);
+	puthex8(" Bit: ", locWithinAByte);
+#endif
+
+	if (errorByte & byteMask) {
+		/* bit needs to be cleared */
+		errorByte &= ~byteMask;
+	} else {
+		/* bit needs to be set */
+		errorByte |= byteMask;
+	}
+
+	/* write back the value with the fixed bit */
+	datap[locWithinAPage * sizeof(uint32_t) + locWithinAWord] = errorByte;
+}
+
+/****************************************************************************
+*  nand_correct_page_bch - Routine to correct bit errors when reading NAND
+*
+*  PURPOSE:
+*     This routine reads the BCH registers to determine if there are any bit
+*     errors during the read of the last 512 bytes of data + ECC bytes.  If
+*     errors exists, the routine fixes it.
+*
+*  PARAMETERS:
+*     datap - Container that holds the 512 byte data
+*
+*  RETURNS:
+*     0 or greater = Number of errors corrected
+*                    (No errors are found or errors have been fixed)
+*    -1 = Error(s) cannot be fixed
+****************************************************************************/
+int nand_bcm_umi_bch_correct_page(uint8_t *datap, uint8_t *readEccData,
+				  int numEccBytes)
+{
+	int numErrors;
+	int errorLocation;
+	int idx;
+	uint32_t regValue;
+
+	/* wait for read ECC to be valid */
+	regValue = nand_bcm_umi_bch_poll_read_ecc_calc();
+
+	/*
+	 * read the control status register to determine if there
+	 * are error'ed bits
+	 * see if errors are correctible
+	 */
+	if ((regValue & REG_UMI_BCH_CTRL_STATUS_UNCORR_ERR) > 0) {
+		int i;
+
+		for (i = 0; i < numEccBytes; i++) {
+			if (readEccData[i] != 0xff) {
+				/* errors cannot be fixed, return -1 */
+				return -1;
+			}
+		}
+		/* If ECC is unprogrammed then we can't correct,
+		 * assume everything OK */
+		return 0;
+	}
+
+	if ((regValue & REG_UMI_BCH_CTRL_STATUS_CORR_ERR) == 0) {
+		/* no errors */
+		return 0;
+	}
+
+	/*
+	 * Fix errored bits by doing the following:
+	 * 1. Read the number of errors in the control and status register
+	 * 2. Read the error location registers that corresponds to the number
+	 *    of errors reported
+	 * 3. Invert the bit in the data
+	 */
+	numErrors = (regValue & REG_UMI_BCH_CTRL_STATUS_NB_CORR_ERROR) >> 20;
+
+	for (idx = 0; idx < numErrors; idx++) {
+		errorLocation =
+		    REG_UMI_BCH_ERR_LOC_ADDR(idx) & REG_UMI_BCH_ERR_LOC_MASK;
+
+		/* Flip bit */
+		nand_bcm_umi_bch_ecc_flip_bit(datap, errorLocation);
+	}
+	/* Errors corrected */
+	return numErrors;
+}
+#endif