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/*
* (C) Copyright 2004-2008 Texas Instruments, <www.ti.com>
* Rohit Choraria <rohitkc@ti.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/io.h>
#include <asm/errno.h>
#include <asm/arch/mem.h>
#include <asm/arch/omap_gpmc.h>
#include <linux/mtd/nand_ecc.h>
#include <nand.h>
static uint8_t cs;
static struct nand_ecclayout hw_nand_oob = GPMC_NAND_HW_ECC_LAYOUT;
/*
* omap_nand_hwcontrol - Set the address pointers corretly for the
* following address/data/command operation
*/
static void omap_nand_hwcontrol(struct mtd_info *mtd, int32_t cmd,
uint32_t ctrl)
{
register struct nand_chip *this = mtd->priv;
/*
* Point the IO_ADDR to DATA and ADDRESS registers instead
* of chip address
*/
switch (ctrl) {
case NAND_CTRL_CHANGE | NAND_CTRL_CLE:
this->IO_ADDR_W = (void __iomem *)&gpmc_cfg->cs[cs].nand_cmd;
break;
case NAND_CTRL_CHANGE | NAND_CTRL_ALE:
this->IO_ADDR_W = (void __iomem *)&gpmc_cfg->cs[cs].nand_adr;
break;
case NAND_CTRL_CHANGE | NAND_NCE:
this->IO_ADDR_W = (void __iomem *)&gpmc_cfg->cs[cs].nand_dat;
break;
}
if (cmd != NAND_CMD_NONE)
writeb(cmd, this->IO_ADDR_W);
}
#ifdef CONFIG_SPL_BUILD
/* Check wait pin as dev ready indicator */
int omap_spl_dev_ready(struct mtd_info *mtd)
{
return gpmc_cfg->status & (1 << 8);
}
#endif
/*
* omap_hwecc_init - Initialize the Hardware ECC for NAND flash in
* GPMC controller
* @mtd: MTD device structure
*
*/
static void omap_hwecc_init(struct nand_chip *chip)
{
/*
* Init ECC Control Register
* Clear all ECC | Enable Reg1
*/
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL, &gpmc_cfg->ecc_size_config);
}
/*
* gen_true_ecc - This function will generate true ECC value, which
* can be used when correcting data read from NAND flash memory core
*
* @ecc_buf: buffer to store ecc code
*
* @return: re-formatted ECC value
*/
static uint32_t gen_true_ecc(uint8_t *ecc_buf)
{
return ecc_buf[0] | (ecc_buf[1] << 16) | ((ecc_buf[2] & 0xF0) << 20) |
((ecc_buf[2] & 0x0F) << 8);
}
/*
* omap_correct_data - Compares the ecc read from nand spare area with ECC
* registers values and corrects one bit error if it has occured
* Further details can be had from OMAP TRM and the following selected links:
* http://en.wikipedia.org/wiki/Hamming_code
* http://www.cs.utexas.edu/users/plaxton/c/337/05f/slides/ErrorCorrection-4.pdf
*
* @mtd: MTD device structure
* @dat: page data
* @read_ecc: ecc read from nand flash
* @calc_ecc: ecc read from ECC registers
*
* @return 0 if data is OK or corrected, else returns -1
*/
static int omap_correct_data(struct mtd_info *mtd, uint8_t *dat,
uint8_t *read_ecc, uint8_t *calc_ecc)
{
uint32_t orig_ecc, new_ecc, res, hm;
uint16_t parity_bits, byte;
uint8_t bit;
/* Regenerate the orginal ECC */
orig_ecc = gen_true_ecc(read_ecc);
new_ecc = gen_true_ecc(calc_ecc);
/* Get the XOR of real ecc */
res = orig_ecc ^ new_ecc;
if (res) {
/* Get the hamming width */
hm = hweight32(res);
/* Single bit errors can be corrected! */
if (hm == 12) {
/* Correctable data! */
parity_bits = res >> 16;
bit = (parity_bits & 0x7);
byte = (parity_bits >> 3) & 0x1FF;
/* Flip the bit to correct */
dat[byte] ^= (0x1 << bit);
} else if (hm == 1) {
printf("Error: Ecc is wrong\n");
/* ECC itself is corrupted */
return 2;
} else {
/*
* hm distance != parity pairs OR one, could mean 2 bit
* error OR potentially be on a blank page..
* orig_ecc: contains spare area data from nand flash.
* new_ecc: generated ecc while reading data area.
* Note: if the ecc = 0, all data bits from which it was
* generated are 0xFF.
* The 3 byte(24 bits) ecc is generated per 512byte
* chunk of a page. If orig_ecc(from spare area)
* is 0xFF && new_ecc(computed now from data area)=0x0,
* this means that data area is 0xFF and spare area is
* 0xFF. A sure sign of a erased page!
*/
if ((orig_ecc == 0x0FFF0FFF) && (new_ecc == 0x00000000))
return 0;
printf("Error: Bad compare! failed\n");
/* detected 2 bit error */
return -1;
}
}
return 0;
}
/*
* omap_calculate_ecc - Generate non-inverted ECC bytes.
*
* Using noninverted ECC can be considered ugly since writing a blank
* page ie. padding will clear the ECC bytes. This is no problem as
* long nobody is trying to write data on the seemingly unused page.
* Reading an erased page will produce an ECC mismatch between
* generated and read ECC bytes that has to be dealt with separately.
* E.g. if page is 0xFF (fresh erased), and if HW ECC engine within GPMC
* is used, the result of read will be 0x0 while the ECC offsets of the
* spare area will be 0xFF which will result in an ECC mismatch.
* @mtd: MTD structure
* @dat: unused
* @ecc_code: ecc_code buffer
*/
static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
uint8_t *ecc_code)
{
u_int32_t val;
/* Start Reading from HW ECC1_Result = 0x200 */
val = readl(&gpmc_cfg->ecc1_result);
ecc_code[0] = val & 0xFF;
ecc_code[1] = (val >> 16) & 0xFF;
ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
/*
* Stop reading anymore ECC vals and clear old results
* enable will be called if more reads are required
*/
writel(0x000, &gpmc_cfg->ecc_config);
return 0;
}
/*
* omap_enable_ecc - This function enables the hardware ecc functionality
* @mtd: MTD device structure
* @mode: Read/Write mode
*/
static void omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
{
struct nand_chip *chip = mtd->priv;
uint32_t val, dev_width = (chip->options & NAND_BUSWIDTH_16) >> 1;
switch (mode) {
case NAND_ECC_READ:
case NAND_ECC_WRITE:
/* Clear the ecc result registers, select ecc reg as 1 */
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
/*
* Size 0 = 0xFF, Size1 is 0xFF - both are 512 bytes
* tell all regs to generate size0 sized regs
* we just have a single ECC engine for all CS
*/
writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL,
&gpmc_cfg->ecc_size_config);
val = (dev_width << 7) | (cs << 1) | (0x1);
writel(val, &gpmc_cfg->ecc_config);
break;
default:
printf("Error: Unrecognized Mode[%d]!\n", mode);
break;
}
}
#ifndef CONFIG_SPL_BUILD
/*
* omap_nand_switch_ecc - switch the ECC operation b/w h/w ecc and s/w ecc.
* The default is to come up on s/w ecc
*
* @hardware - 1 -switch to h/w ecc, 0 - s/w ecc
*
*/
void omap_nand_switch_ecc(int32_t hardware)
{
struct nand_chip *nand;
struct mtd_info *mtd;
if (nand_curr_device < 0 ||
nand_curr_device >= CONFIG_SYS_MAX_NAND_DEVICE ||
!nand_info[nand_curr_device].name) {
printf("Error: Can't switch ecc, no devices available\n");
return;
}
mtd = &nand_info[nand_curr_device];
nand = mtd->priv;
nand->options |= NAND_OWN_BUFFERS;
/* Reset ecc interface */
nand->ecc.read_page = NULL;
nand->ecc.write_page = NULL;
nand->ecc.read_oob = NULL;
nand->ecc.write_oob = NULL;
nand->ecc.hwctl = NULL;
nand->ecc.correct = NULL;
nand->ecc.calculate = NULL;
/* Setup the ecc configurations again */
if (hardware) {
nand->ecc.mode = NAND_ECC_HW;
nand->ecc.layout = &hw_nand_oob;
nand->ecc.size = 512;
nand->ecc.bytes = 3;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data;
nand->ecc.calculate = omap_calculate_ecc;
omap_hwecc_init(nand);
printf("HW ECC selected\n");
} else {
nand->ecc.mode = NAND_ECC_SOFT;
/* Use mtd default settings */
nand->ecc.layout = NULL;
printf("SW ECC selected\n");
}
/* Update NAND handling after ECC mode switch */
nand_scan_tail(mtd);
nand->options &= ~NAND_OWN_BUFFERS;
}
#endif /* CONFIG_SPL_BUILD */
/*
* Board-specific NAND initialization. The following members of the
* argument are board-specific:
* - IO_ADDR_R: address to read the 8 I/O lines of the flash device
* - IO_ADDR_W: address to write the 8 I/O lines of the flash device
* - cmd_ctrl: hardwarespecific function for accesing control-lines
* - waitfunc: hardwarespecific function for accesing device ready/busy line
* - ecc.hwctl: function to enable (reset) hardware ecc generator
* - ecc.mode: mode of ecc, see defines
* - chip_delay: chip dependent delay for transfering data from array to
* read regs (tR)
* - options: various chip options. They can partly be set to inform
* nand_scan about special functionality. See the defines for further
* explanation
*/
int board_nand_init(struct nand_chip *nand)
{
int32_t gpmc_config = 0;
cs = 0;
/*
* xloader/Uboot's gpmc configuration would have configured GPMC for
* nand type of memory. The following logic scans and latches on to the
* first CS with NAND type memory.
* TBD: need to make this logic generic to handle multiple CS NAND
* devices.
*/
while (cs < GPMC_MAX_CS) {
/* Check if NAND type is set */
if ((readl(&gpmc_cfg->cs[cs].config1) & 0xC00) == 0x800) {
/* Found it!! */
break;
}
cs++;
}
if (cs >= GPMC_MAX_CS) {
printf("NAND: Unable to find NAND settings in "
"GPMC Configuration - quitting\n");
return -ENODEV;
}
gpmc_config = readl(&gpmc_cfg->config);
/* Disable Write protect */
gpmc_config |= 0x10;
writel(gpmc_config, &gpmc_cfg->config);
nand->IO_ADDR_R = (void __iomem *)&gpmc_cfg->cs[cs].nand_dat;
nand->IO_ADDR_W = (void __iomem *)&gpmc_cfg->cs[cs].nand_cmd;
nand->cmd_ctrl = omap_nand_hwcontrol;
nand->options = NAND_NO_PADDING | NAND_CACHEPRG | NAND_NO_AUTOINCR;
/* If we are 16 bit dev, our gpmc config tells us that */
if ((readl(&gpmc_cfg->cs[cs].config1) & 0x3000) == 0x1000)
nand->options |= NAND_BUSWIDTH_16;
nand->chip_delay = 100;
/* Default ECC mode */
#ifndef CONFIG_SPL_BUILD
nand->ecc.mode = NAND_ECC_SOFT;
#else
nand->ecc.mode = NAND_ECC_HW;
nand->ecc.layout = &hw_nand_oob;
nand->ecc.size = CONFIG_SYS_NAND_ECCSIZE;
nand->ecc.bytes = CONFIG_SYS_NAND_ECCBYTES;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data;
nand->ecc.calculate = omap_calculate_ecc;
omap_hwecc_init(nand);
if (nand->options & NAND_BUSWIDTH_16)
nand->read_buf = nand_read_buf16;
else
nand->read_buf = nand_read_buf;
nand->dev_ready = omap_spl_dev_ready;
#endif
return 0;
}