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Commit 8c61b7a7 authored by Segher Boessenkool's avatar Segher Boessenkool Committed by David Woodhouse
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[MTD] [NAND] Use rslib for CAFÉ ECC 



Signed-off-by: default avatarSegher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent d7e5a546

drivers/mtd/nand/Kconfig

+7 −5
Original line number Diff line number Diff line
@@ -234,6 +234,8 @@ config MTD_NAND_BASLER_EXCITE 
config MTD_NAND_CAFE

	tristate "NAND support for OLPC CAFÉ chip"

	depends on PCI

	select REED_SOLOMON

	select REED_SOLOMON_DEC16

	help

	  Use NAND flash attached to the CAFÉ chip designed for the $100

	  laptop.

drivers/mtd/nand/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -28,4 +28,4 @@ obj-$(CONFIG_MTD_NAND_CM_X270) += cmx270_nand.o 
obj-$(CONFIG_MTD_NAND_BASLER_EXCITE)	+= excite_nandflash.o



nand-objs := nand_base.o nand_bbt.o

cafe_nand-objs := cafe.o cafe_ecc.o
 
cafe_nand-objs := cafe.o

drivers/mtd/nand/cafe.c

+98 −12
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#undef DEBUG

#include <linux/mtd/mtd.h>

#include <linux/mtd/nand.h>

#include <linux/rslib.h>

#include <linux/pci.h>

#include <linux/delay.h>

#include <linux/interrupt.h>
@@ -46,13 +47,11 @@ 
#define CAFE_GLOBAL_IRQ_MASK	0x300c

#define CAFE_NAND_RESET		0x3034



int cafe_correct_ecc(unsigned char *buf,

		     unsigned short *chk_syndrome_list);



struct cafe_priv {

	struct nand_chip nand;

	struct pci_dev *pdev;

	void __iomem *mmio;

	struct rs_control *rs;

	uint32_t ctl1;

	uint32_t ctl2;

	int datalen;
@@ -374,28 +373,66 @@ static int cafe_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip, 
	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);



	if (checkecc && cafe_readl(cafe, NAND_ECC_RESULT) & (1<<18)) {

		unsigned short syn[8];

		int i;

		unsigned short syn[8], pat[4];

		int pos[4];

		u8 *oob = chip->oob_poi;

		int i, n;



		for (i=0; i<8; i+=2) {

			uint32_t tmp = cafe_readl(cafe, NAND_ECC_SYN01 + (i*2));

			syn[i] = tmp & 0xfff;

			syn[i+1] = (tmp >> 16) & 0xfff;

			syn[i] = cafe->rs->index_of[tmp & 0xfff];

			syn[i+1] = cafe->rs->index_of[(tmp >> 16) & 0xfff];

		}



		if ((i = cafe_correct_ecc(buf, syn)) < 0) {

		n = decode_rs16(cafe->rs, NULL, NULL, 1367, syn, 0, pos, 0,

		                pat);



		for (i = 0; i < n; i++) {

			int p = pos[i];



			/* The 12-bit symbols are mapped to bytes here */



			if (p > 1374) {

				/* out of range */

				n = -1374;

			} else if (p == 0) {

				/* high four bits do not correspond to data */

				if (pat[i] > 0xff)

					n = -2048;

				else

					buf[0] ^= pat[i];

			} else if (p == 1365) {

				buf[2047] ^= pat[i] >> 4;

				oob[0] ^= pat[i] << 4;

			} else if (p > 1365) {

				if ((p & 1) == 1) {

					oob[3*p/2 - 2048] ^= pat[i] >> 4;

					oob[3*p/2 - 2047] ^= pat[i] << 4;

				} else {

					oob[3*p/2 - 2049] ^= pat[i] >> 8;

					oob[3*p/2 - 2048] ^= pat[i];

				}

			} else if ((p & 1) == 1) {

				buf[3*p/2] ^= pat[i] >> 4;

				buf[3*p/2 + 1] ^= pat[i] << 4;

			} else {

				buf[3*p/2 - 1] ^= pat[i] >> 8;

				buf[3*p/2] ^= pat[i];

			}

		}



		if (n < 0) {

			dev_dbg(&cafe->pdev->dev, "Failed to correct ECC at %08x\n",

				cafe_readl(cafe, NAND_ADDR2) * 2048);

			for (i = 0; i < 0x5c; i += 4)

				printk("Register %x: %08x\n", i, readl(cafe->mmio + i));

			mtd->ecc_stats.failed++;

		} else {

			dev_dbg(&cafe->pdev->dev, "Corrected %d symbol errors\n", i);

			mtd->ecc_stats.corrected += i;

			dev_dbg(&cafe->pdev->dev, "Corrected %d symbol errors\n", n);

			mtd->ecc_stats.corrected += n;

		}

	}





	return 0;

}
@@ -525,6 +562,48 @@ static int cafe_nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip) 
	return 0;

}



/* F_2[X]/(X**6+X+1)  */

static unsigned short __devinit gf64_mul(u8 a, u8 b)

{

	u8 c;

	unsigned int i;



	c = 0;

	for (i = 0; i < 6; i++) {

		if (a & 1)

			c ^= b;

		a >>= 1;

		b <<= 1;

		if ((b & 0x40) != 0)

			b ^= 0x43;

	}



	return c;

}



/* F_64[X]/(X**2+X+A**-1) with A the generator of F_64[X]  */

static u16 __devinit gf4096_mul(u16 a, u16 b)

{

	u8 ah, al, bh, bl, ch, cl;



	ah = a >> 6;

	al = a & 0x3f;

	bh = b >> 6;

	bl = b & 0x3f;



	ch = gf64_mul(ah ^ al, bh ^ bl) ^ gf64_mul(al, bl);

	cl = gf64_mul(gf64_mul(ah, bh), 0x21) ^ gf64_mul(al, bl);



	return (ch << 6) ^ cl;

}



static int __devinit cafe_mul(int x)

{

	if (x == 0)

		return 1;

	return gf4096_mul(x, 0xe01);

}



static int __devinit cafe_nand_probe(struct pci_dev *pdev,

				     const struct pci_device_id *ent)

{
@@ -564,6 +643,12 @@ static int __devinit cafe_nand_probe(struct pci_dev *pdev, 
	}

	cafe->nand.buffers = (void *)cafe->dmabuf + 2112;



	cafe->rs = init_rs_non_canonical(12, &cafe_mul, 0, 1, 8);

	if (!cafe->rs) {

		err = -ENOMEM;

		goto out_ior;

	}



	cafe->nand.cmdfunc = cafe_nand_cmdfunc;

	cafe->nand.dev_ready = cafe_device_ready;

	cafe->nand.read_byte = cafe_read_byte;
@@ -713,6 +798,7 @@ static void __devexit cafe_nand_remove(struct pci_dev *pdev) 
	cafe_writel(cafe, ~1 & cafe_readl(cafe, GLOBAL_IRQ_MASK), GLOBAL_IRQ_MASK);

	free_irq(pdev->irq, mtd);

	nand_release(mtd);

	free_rs(cafe->rs);

	pci_iounmap(pdev, cafe->mmio);

	dma_free_coherent(&cafe->pdev->dev, 2112, cafe->dmabuf, cafe->dmaaddr);

	kfree(mtd);