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/*
* (C) Copyright 2007 STMicroelectronics, <www.st.com>
* (C) Copyright 2009 Alessandro Rubini <rubini@unipv.it>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <nand.h>
#include <asm/io.h>
static inline int parity(int b) /* b is really a byte; returns 0 or ~0 */
{
__asm__ __volatile__(
"eor %0, %0, %0, lsr #4\n\t"
"eor %0, %0, %0, lsr #2\n\t"
"eor %0, %0, %0, lsr #1\n\t"
"ands %0, %0, #1\n\t"
"subne %0, %0, #2\t"
: "=r" (b) : "0" (b));
return b;
}
/*
* This is the ECC routine used in hardware, according to the manual.
* HW claims to make the calculation but not the correction; so we must
* recalculate the bytes for a comparison.
*/
static int ecc512(const unsigned char *data, unsigned char *ecc)
{
int gpar = 0;
int i, val, par;
int pbits = 0; /* P8, P16, ... P2048 */
int pprime = 0; /* P8', P16', ... P2048' */
int lowbits; /* P1, P2, P4 and primes */
for (i = 0; i < 512; i++) {
par = parity((val = data[i]));
gpar ^= val;
pbits ^= (i & par);
}
/*
* Ok, now gpar is global parity (xor of all bytes)
* pbits are all the parity bits (non-prime ones)
*/
par = parity(gpar);
pprime = pbits ^ par;
/* Put low bits in the right position for ecc[2] (bits 7..2) */
lowbits = 0
| (parity(gpar & 0xf0) & 0x80) /* P4 */
| (parity(gpar & 0x0f) & 0x40) /* P4' */
| (parity(gpar & 0xcc) & 0x20) /* P2 */
| (parity(gpar & 0x33) & 0x10) /* P2' */
| (parity(gpar & 0xaa) & 0x08) /* P1 */
| (parity(gpar & 0x55) & 0x04); /* P1' */
ecc[2] = ~(lowbits | ((pbits & 0x100) >> 7) | ((pprime & 0x100) >> 8));
/* now intermix bits for ecc[1] (P1024..P128') and ecc[0] (P64..P8') */
ecc[1] = ~( (pbits & 0x80) >> 0 | ((pprime & 0x80) >> 1)
| ((pbits & 0x40) >> 1) | ((pprime & 0x40) >> 2)
| ((pbits & 0x20) >> 2) | ((pprime & 0x20) >> 3)
| ((pbits & 0x10) >> 3) | ((pprime & 0x10) >> 4));
ecc[0] = ~( (pbits & 0x8) << 4 | ((pprime & 0x8) << 3)
| ((pbits & 0x4) << 3) | ((pprime & 0x4) << 2)
| ((pbits & 0x2) << 2) | ((pprime & 0x2) << 1)
| ((pbits & 0x1) << 1) | ((pprime & 0x1) << 0));
return 0;
}
/* This is the method in the chip->ecc field */
static int nomadik_ecc_calculate(struct mtd_info *mtd, const uint8_t *dat,
uint8_t *ecc_code)
{
return ecc512(dat, ecc_code);
}
static int nomadik_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
uint8_t *r_ecc, uint8_t *c_ecc)
{
struct nand_chip *chip = mtd->priv;
uint32_t r, c, d, diff; /*read, calculated, xor of them */
if (!memcmp(r_ecc, c_ecc, chip->ecc.bytes))
return 0;
/* Reorder the bytes into ascending-order 24 bits -- see manual */
r = r_ecc[2] << 22 | r_ecc[1] << 14 | r_ecc[0] << 6 | r_ecc[2] >> 2;
c = c_ecc[2] << 22 | c_ecc[1] << 14 | c_ecc[0] << 6 | c_ecc[2] >> 2;
diff = (r ^ c) & ((1<<24)-1); /* use 24 bits only */
/* If 12 bits are different, one per pair, it's correctable */
if (((diff | (diff>>1)) & 0x555555) == 0x555555) {
int bit = ((diff & 2) >> 1)
| ((diff & 0x8) >> 2) | ((diff & 0x20) >> 3);
int byte;
d = diff >> 6; /* remove bit-order info */
byte = ((d & 2) >> 1)
| ((d & 0x8) >> 2) | ((d & 0x20) >> 3)
| ((d & 0x80) >> 4) | ((d & 0x200) >> 5)
| ((d & 0x800) >> 6) | ((d & 0x2000) >> 7)
| ((d & 0x8000) >> 8) | ((d & 0x20000) >> 9);
/* correct the single bit */
dat[byte] ^= 1<<bit;
return 0;
}
/* If 1 bit only differs, it's one bit error in ECC, ignore */
if ((diff ^ (1 << (ffs(diff) - 1))) == 0)
return 0;
/* Otherwise, uncorrectable */
return -1;
}
static void nomadik_ecc_hwctl(struct mtd_info *mtd, int mode)
{ /* mandatory in the structure but not used here */ }
/* This is the layout used by older installations, we keep compatible */
struct nand_ecclayout nomadik_ecc_layout = {
.eccbytes = 3 * 4,
.eccpos = { /* each subpage has 16 bytes: pos 2,3,4 hosts ECC */
0x02, 0x03, 0x04,
0x12, 0x13, 0x14,
0x22, 0x23, 0x24,
0x32, 0x33, 0x34},
.oobfree = { {0x08, 0x08}, {0x18, 0x08}, {0x28, 0x08}, {0x38, 0x08} },
};
#define MASK_ALE (1 << 24) /* our ALE is AD21 */
#define MASK_CLE (1 << 23) /* our CLE is AD22 */
/* This is copied from the AT91SAM9 devices (Stelian Pop, Lead Tech Design) */
static void nomadik_nand_hwcontrol(struct mtd_info *mtd,
int cmd, unsigned int ctrl)
{
struct nand_chip *this = mtd->priv;
u32 pcr0 = readl(REG_FSMC_PCR0);
if (ctrl & NAND_CTRL_CHANGE) {
ulong IO_ADDR_W = (ulong) this->IO_ADDR_W;
IO_ADDR_W &= ~(MASK_ALE | MASK_CLE);
if (ctrl & NAND_CLE)
IO_ADDR_W |= MASK_CLE;
if (ctrl & NAND_ALE)
IO_ADDR_W |= MASK_ALE;
if (ctrl & NAND_NCE)
writel(pcr0 | 0x4, REG_FSMC_PCR0);
else
writel(pcr0 & ~0x4, REG_FSMC_PCR0);
this->IO_ADDR_W = (void *) IO_ADDR_W;
this->IO_ADDR_R = (void *) IO_ADDR_W;
}
if (cmd != NAND_CMD_NONE)
writeb(cmd, this->IO_ADDR_W);
}
/* Returns 1 when ready; upper layers timeout at 20ms with timer routines */
static int nomadik_nand_ready(struct mtd_info *mtd)
{
return 1; /* The ready bit is handled in hardware */
}
/* Copy a buffer 32bits at a time: faster than defualt method which is 8bit */
static void nomadik_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
int i;
struct nand_chip *chip = mtd->priv;
u32 *p = (u32 *) buf;
len >>= 2;
writel(0, REG_FSMC_ECCR0);
for (i = 0; i < len; i++)
p[i] = readl(chip->IO_ADDR_R);
}
int board_nand_init(struct nand_chip *chip)
{
/* Set up the FSMC_PCR0 for nand access*/
writel(0x0000004a, REG_FSMC_PCR0);
/* Set up FSMC_PMEM0, FSMC_PATT0 with timing data for access */
writel(0x00020401, REG_FSMC_PMEM0);
writel(0x00020404, REG_FSMC_PATT0);
chip->options = NAND_COPYBACK | NAND_CACHEPRG | NAND_NO_PADDING;
chip->cmd_ctrl = nomadik_nand_hwcontrol;
chip->dev_ready = nomadik_nand_ready;
/* The chip allows 32bit reads, so avoid the default 8bit copy */
chip->read_buf = nomadik_nand_read_buf;
/* ECC: follow the hardware-defined rulse, but do it in sw */
chip->ecc.mode = NAND_ECC_HW;
chip->ecc.bytes = 3;
chip->ecc.size = 512;
chip->ecc.strength = 1;
chip->ecc.layout = &nomadik_ecc_layout;
chip->ecc.calculate = nomadik_ecc_calculate;
chip->ecc.hwctl = nomadik_ecc_hwctl;
chip->ecc.correct = nomadik_ecc_correct;
return 0;
}
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