[U-Boot] [PATCH v2] Nand driver for Nomadik SoC

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 16:04 Sat 07 Feb     , Alessandro Rubini wrote:
> From: Alessandro Rubini <rubini@unipv.it>
> 
> This driver implements the ECC algorithm described in
> the CPU data sheet and uses the OOB layout chosen in
> already-released development systems (shipped with a custom-made
> u-boot 1.3.1).
> 
> Signed-off-by: Alessandro Rubini <rubini@unipv.it>
> Acked-by: Andrea Gallo <andrea.gallo@stnwireless.com>
> ---
> 
> About V2: I noticed I forgot to run through checkpatch, I fixed all
> whitespace warnings.I left 2 of them (space after open parens) as I
> think the bit fiddling is more readable this way.
> 
>  cpu/arm926ejs/nomadik/Makefile |    6 +-
>  cpu/arm926ejs/nomadik/nand.c   |  240 ++++++++++++++++++++++++++++++++++++++++
>  include/configs/nmdk8815.h     |   14 +--
>  3 files changed, 250 insertions(+), 10 deletions(-)
>  create mode 100644 cpu/arm926ejs/nomadik/nand.c
> 
> diff --git a/cpu/arm926ejs/nomadik/Makefile b/cpu/arm926ejs/nomadik/Makefile
> index e3bd2ee..9c73327 100644
> --- a/cpu/arm926ejs/nomadik/Makefile
> +++ b/cpu/arm926ejs/nomadik/Makefile
> @@ -25,11 +25,13 @@ include $(TOPDIR)/config.mk
>  
>  LIB	= $(obj)lib$(SOC).a
>  
> -COBJS	= timer.o
>  SOBJS	= reset.o
>  
> +COBJS-y	= timer.o
> +COBJS-$(CONFIG_CMD_NAND) += nand.o
> +
>  SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
> -OBJS	:= $(addprefix $(obj),$(COBJS)) $(addprefix $(obj),$(SOBJS))
> +OBJS	:= $(addprefix $(obj),$(COBJS-y)) $(addprefix $(obj),$(SOBJS))
please use this

SRCS	:= $(SOBJS:.o=.S) $(COBJS-y:.o=.c)
OBJS	:= $(addprefix $(obj),$(COBJS-y))
SOBJS	:= $(addprefix $(obj),$(SOBJS))
>  
>  all:	$(obj).depend $(LIB)
>  
> diff --git a/cpu/arm926ejs/nomadik/nand.c b/cpu/arm926ejs/nomadik/nand.c
> new file mode 100644
> index 0000000..22ee591
> --- /dev/null
> +++ b/cpu/arm926ejs/nomadik/nand.c
> @@ -0,0 +1,240 @@
> +/*
> + * (C) Copyright 2007 STMicroelectronics, <www.st.com>
> + * (C) Copyright 2009 Alessandro Rubini <rubini@unipv.it>
> + *
> + * 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 <nand.h>
> +#include <asm/io.h>
> +
> +#ifdef __arm__ /* Assembly version of the parity-of-byte procedure */
we should need only one
> +
> +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;
> +}
> +
> +#else /* Equivalent in C, which I used for testing the main procedure */
> +
> +static inline int parity(int b)
> +{
> +	b = b ^ (b >> 4);
> +	b = b ^ (b >> 2);
> +	return (b ^ (b>>1)) & 1
> +		? ~0 : 0;
> +}
> +
> +#endif
> +
> +/*
> + * 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(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  */
						     ^^
whitespace please fix
> +		| (parity(gpar & 0x0f) & 0x40)	/* P4' */
> +		| (parity(gpar & 0xcc) & 0x20)	/* P2  */
						     ^^
whitespace please fix
> +		| (parity(gpar & 0x33) & 0x10)	/* P2' */
> +		| (parity(gpar & 0xaa) & 0x08)	/* P1  */
						     ^^
whitespace please fix
> +		| (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,
	     ^^
whitespace please fix
> +				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,
please add a space before and after '*'
> +	.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 REG_FSMC_PCR0	(NOMADIK_FSMC_BASE + 0x40)
> +#define REG_FSMC_PMEM0	(NOMADIK_FSMC_BASE + 0x48)
> +#define REG_FSMC_PATT0	(NOMADIK_FSMC_BASE + 0x4c)
> +#define REG_FSMC_ECCR0	(NOMADIK_FSMC_BASE + 0x54)
please move this to a header
> +
> +#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);
				     ^^
whitespace please fix
> +		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;
please add an empty line
> +	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.layout = &nomadik_ecc_layout;
> +	chip->ecc.calculate = nomadik_ecc_calculate;
> +	chip->ecc.hwctl = nomadik_ecc_hwctl;
> +	chip->ecc.correct = nomadik_ecc_correct;
> +
> +	return 0;
> +}
Best Regards,
J.