[MTD] NAND Modularize read function
Split the core of the read function out and implement
seperate handling functions for software and hardware
ECC.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 49bca24..21fce2b 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -976,256 +976,224 @@
#endif
/**
- * nand_read - [MTD Interface] MTD compability function for nand_do_read_ecc
- * @mtd: MTD device structure
- * @from: offset to read from
- * @len: number of bytes to read
- * @retlen: pointer to variable to store the number of read bytes
- * @buf: the databuffer to put data
- *
- * This function simply calls nand_do_read_ecc with oob buffer and oobsel = NULL
- * and flags = 0xff
+ * nand_read_page_swecc - {REPLACABLE] software ecc based page read function
+ * @mtd: mtd info structure
+ * @chip: nand chip info structure
+ * @buf: buffer to store read data
*/
-static int nand_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, uint8_t *buf)
+static int nand_read_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
+ uint8_t *buf)
{
- return nand_do_read_ecc(mtd, from, len, retlen, buf, NULL, &mtd->oobinfo, 0xff);
+ int i, eccsize = chip->ecc.size;
+ int eccbytes = chip->ecc.bytes;
+ int eccsteps = chip->ecc.steps;
+ uint8_t *p = buf;
+ uint8_t *ecc_calc = chip->oob_buf + mtd->oobsize;
+ uint8_t *ecc_code = ecc_calc + mtd->oobsize;
+ int *eccpos = chip->autooob->eccpos;
+
+ chip->read_buf(mtd, buf, mtd->writesize);
+ chip->read_buf(mtd, chip->oob_buf, mtd->oobsize);
+
+ if (chip->ecc.mode == NAND_ECC_NONE)
+ return 0;
+
+ for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
+ chip->ecc.calculate(mtd, p, &ecc_calc[i]);
+
+ for (i = 0; i < chip->ecc.total; i++)
+ ecc_code[i] = chip->oob_buf[eccpos[i]];
+
+ eccsteps = chip->ecc.steps;
+ p = buf;
+
+ for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+ int stat;
+
+ stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
+ if (stat == -1)
+ mtd->ecc_stats.failed++;
+ else
+ mtd->ecc_stats.corrected += stat;
+ }
+ return 0;
}
/**
- * nand_do_read_ecc - [MTD Interface] Read data with ECC
+ * nand_read_page_hwecc - {REPLACABLE] hardware ecc based page read function
+ * @mtd: mtd info structure
+ * @chip: nand chip info structure
+ * @buf: buffer to store read data
+ *
+ * Not for syndrome calculating ecc controllers which need a special oob layout
+ */
+static int nand_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
+ uint8_t *buf)
+{
+ int i, eccsize = chip->ecc.size;
+ int eccbytes = chip->ecc.bytes;
+ int eccsteps = chip->ecc.steps;
+ uint8_t *p = buf;
+ uint8_t *ecc_calc = chip->oob_buf + mtd->oobsize;
+ uint8_t *ecc_code = ecc_calc + mtd->oobsize;
+ int *eccpos = chip->autooob->eccpos;
+
+ for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+ chip->ecc.hwctl(mtd, NAND_ECC_READ);
+ chip->read_buf(mtd, p, eccsize);
+ chip->ecc.calculate(mtd, p, &ecc_calc[i]);
+ }
+ chip->read_buf(mtd, chip->oob_buf, mtd->oobsize);
+
+ for (i = 0; i < chip->ecc.total; i++)
+ ecc_code[i] = chip->oob_buf[eccpos[i]];
+
+ eccsteps = chip->ecc.steps;
+ p = buf;
+
+ for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+ int stat;
+
+ stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
+ if (stat == -1)
+ mtd->ecc_stats.failed++;
+ else
+ mtd->ecc_stats.corrected += stat;
+ }
+ return 0;
+}
+
+/**
+ * nand_read_page_syndrome - {REPLACABLE] hardware ecc syndrom based page read
+ * @mtd: mtd info structure
+ * @chip: nand chip info structure
+ * @buf: buffer to store read data
+ *
+ * The hw generator calculates the error syndrome automatically. Therefor
+ * we need a special oob layout and .
+ */
+static int nand_read_page_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
+ uint8_t *buf)
+{
+ int i, eccsize = chip->ecc.size;
+ int eccbytes = chip->ecc.bytes;
+ int eccsteps = chip->ecc.steps;
+ uint8_t *p = buf;
+ uint8_t *oob = chip->oob_buf;
+
+ for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+ int stat;
+
+ chip->ecc.hwctl(mtd, NAND_ECC_READ);
+ chip->read_buf(mtd, p, eccsize);
+
+ if (chip->ecc.prepad) {
+ chip->read_buf(mtd, oob, chip->ecc.prepad);
+ oob += chip->ecc.prepad;
+ }
+
+ chip->ecc.hwctl(mtd, NAND_ECC_READSYN);
+ chip->read_buf(mtd, oob, eccbytes);
+ stat = chip->ecc.correct(mtd, p, oob, NULL);
+
+ if (stat == -1)
+ mtd->ecc_stats.failed++;
+ else
+ mtd->ecc_stats.corrected += stat;
+
+ oob += eccbytes;
+
+ if (chip->ecc.postpad) {
+ chip->read_buf(mtd, oob, chip->ecc.postpad);
+ oob += chip->ecc.postpad;
+ }
+ }
+
+ /* Calculate remaining oob bytes */
+ i = oob - chip->oob_buf;
+ if (i)
+ chip->read_buf(mtd, oob, i);
+
+ return 0;
+}
+
+/**
+ * nand_do_read - [Internal] Read data with ECC
+ *
* @mtd: MTD device structure
* @from: offset to read from
* @len: number of bytes to read
* @retlen: pointer to variable to store the number of read bytes
* @buf: the databuffer to put data
- * @oob_buf: filesystem supplied oob data buffer (can be NULL)
- * @oobsel: oob selection structure
- * @flags: flag to indicate if nand_get_device/nand_release_device should be preformed
- * and how many corrected error bits are acceptable:
- * bits 0..7 - number of tolerable errors
- * bit 8 - 0 == do not get/release chip, 1 == get/release chip
*
- * NAND read with ECC
+ * Internal function. Called with chip held.
*/
-int nand_do_read_ecc(struct mtd_info *mtd, loff_t from, size_t len,
- size_t *retlen, uint8_t *buf, uint8_t *oob_buf, struct nand_oobinfo *oobsel, int flags)
+int nand_do_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, uint8_t *buf)
{
-
- int i, j, col, realpage, page, end, ecc, chipnr, sndcmd = 1;
- int read = 0, oob = 0, ecc_status = 0, ecc_failed = 0;
+ int chipnr, page, realpage, col, bytes, aligned;
struct nand_chip *chip = mtd->priv;
- uint8_t *data_poi, *oob_data = oob_buf;
- uint8_t ecc_calc[32];
- uint8_t ecc_code[32];
- int eccmode, eccsteps;
- int *oob_config, datidx;
- int blockcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
- int eccbytes;
- int compareecc = 1;
- int oobreadlen;
+ struct mtd_ecc_stats stats;
+ int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
+ int sndcmd = 1;
+ int ret = 0;
+ uint32_t readlen = len;
+ uint8_t *bufpoi;
- DEBUG(MTD_DEBUG_LEVEL3, "nand_read_ecc: from = 0x%08x, len = %i\n", (unsigned int)from, (int)len);
+ stats = mtd->ecc_stats;
- /* Do not allow reads past end of device */
- if ((from + len) > mtd->size) {
- DEBUG(MTD_DEBUG_LEVEL0, "nand_read_ecc: Attempt read beyond end of device\n");
- *retlen = 0;
- return -EINVAL;
- }
-
- /* Grab the lock and see if the device is available */
- if (flags & NAND_GET_DEVICE)
- nand_get_device(chip, mtd, FL_READING);
-
- /* Autoplace of oob data ? Use the default placement scheme */
- if (oobsel->useecc == MTD_NANDECC_AUTOPLACE)
- oobsel = chip->autooob;
-
- eccmode = oobsel->useecc ? chip->ecc.mode : NAND_ECC_NONE;
- oob_config = oobsel->eccpos;
-
- /* Select the NAND device */
chipnr = (int)(from >> chip->chip_shift);
chip->select_chip(mtd, chipnr);
- /* First we calculate the starting page */
realpage = (int)(from >> chip->page_shift);
page = realpage & chip->pagemask;
- /* Get raw starting column */
- col = from & (mtd->writesize - 1);
+ col = (int)(from & (mtd->writesize - 1));
- end = mtd->writesize;
- ecc = chip->ecc.size;
- eccbytes = chip->ecc.bytes;
+ while(1) {
+ bytes = min(mtd->writesize - col, readlen);
+ aligned = (bytes == mtd->writesize);
- if ((eccmode == NAND_ECC_NONE) || (chip->options & NAND_HWECC_SYNDROME))
- compareecc = 0;
+ /* Is the current page in the buffer ? */
+ if (realpage != chip->pagebuf) {
+ bufpoi = aligned ? buf : chip->data_buf;
- oobreadlen = mtd->oobsize;
- if (chip->options & NAND_HWECC_SYNDROME)
- oobreadlen -= oobsel->eccbytes;
+ if (likely(sndcmd)) {
+ chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
+ sndcmd = 0;
+ }
- /* Loop until all data read */
- while (read < len) {
-
- int aligned = (!col && (len - read) >= end);
- /*
- * If the read is not page aligned, we have to read into data buffer
- * due to ecc, else we read into return buffer direct
- */
- if (aligned)
- data_poi = &buf[read];
- else
- data_poi = chip->data_buf;
-
- /* Check, if we have this page in the buffer
- *
- * FIXME: Make it work when we must provide oob data too,
- * check the usage of data_buf oob field
- */
- if (realpage == chip->pagebuf && !oob_buf) {
- /* aligned read ? */
- if (aligned)
- memcpy(data_poi, chip->data_buf, end);
- goto readdata;
- }
-
- /* Check, if we must send the read command */
- if (sndcmd) {
- chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
- sndcmd = 0;
- }
-
- /* get oob area, if we have no oob buffer from fs-driver */
- if (!oob_buf || oobsel->useecc == MTD_NANDECC_AUTOPLACE ||
- oobsel->useecc == MTD_NANDECC_AUTOPL_USR)
- oob_data = &chip->data_buf[end];
-
- eccsteps = chip->ecc.steps;
-
- switch (eccmode) {
- case NAND_ECC_NONE:{
- /* No ECC, Read in a page */
- static unsigned long lastwhinge = 0;
- if ((lastwhinge / HZ) != (jiffies / HZ)) {
- printk(KERN_WARNING
- "Reading data from NAND FLASH without ECC is not recommended\n");
- lastwhinge = jiffies;
- }
- chip->read_buf(mtd, data_poi, end);
+ /* Now read the page into the buffer */
+ ret = chip->ecc.read_page(mtd, chip, bufpoi);
+ if (ret < 0)
break;
+
+ /* Transfer not aligned data */
+ if (!aligned) {
+ chip->pagebuf = realpage;
+ memcpy(buf, chip->data_buf + col, bytes);
}
- case NAND_ECC_SOFT: /* Software ECC 3/256: Read in a page + oob data */
- chip->read_buf(mtd, data_poi, end);
- for (i = 0, datidx = 0; eccsteps; eccsteps--, i += 3, datidx += ecc)
- chip->ecc.calculate(mtd, &data_poi[datidx], &ecc_calc[i]);
- break;
-
- default:
- for (i = 0, datidx = 0; eccsteps; eccsteps--, i += eccbytes, datidx += ecc) {
- chip->ecc.hwctl(mtd, NAND_ECC_READ);
- chip->read_buf(mtd, &data_poi[datidx], ecc);
-
- /* HW ecc with syndrome calculation must read the
- * syndrome from flash immidiately after the data */
- if (!compareecc) {
- /* Some hw ecc generators need to know when the
- * syndrome is read from flash */
- chip->ecc.hwctl(mtd, NAND_ECC_READSYN);
- chip->read_buf(mtd, &oob_data[i], eccbytes);
- /* We calc error correction directly, it checks the hw
- * generator for an error, reads back the syndrome and
- * does the error correction on the fly */
- ecc_status = chip->ecc.correct(mtd, &data_poi[datidx], &oob_data[i], &ecc_code[i]);
- if ((ecc_status == -1) || (ecc_status > (flags && 0xff))) {
- DEBUG(MTD_DEBUG_LEVEL0, "nand_read_ecc: "
- "Failed ECC read, page 0x%08x on chip %d\n", page, chipnr);
- ecc_failed++;
- }
- } else {
- chip->ecc.calculate(mtd, &data_poi[datidx], &ecc_calc[i]);
- }
+ if (!(chip->options & NAND_NO_READRDY)) {
+ /*
+ * Apply delay or wait for ready/busy pin. Do
+ * this before the AUTOINCR check, so no
+ * problems arise if a chip which does auto
+ * increment is marked as NOAUTOINCR by the
+ * board driver.
+ */
+ if (!chip->dev_ready)
+ udelay(chip->chip_delay);
+ else
+ nand_wait_ready(mtd);
}
- break;
- }
-
- /* read oobdata */
- chip->read_buf(mtd, &oob_data[mtd->oobsize - oobreadlen], oobreadlen);
-
- /* Skip ECC check, if not requested (ECC_NONE or HW_ECC with syndromes) */
- if (!compareecc)
- goto readoob;
-
- /* Pick the ECC bytes out of the oob data */
- for (j = 0; j < oobsel->eccbytes; j++)
- ecc_code[j] = oob_data[oob_config[j]];
-
- /* correct data, if necessary */
- for (i = 0, j = 0, datidx = 0; i < chip->ecc.steps; i++, datidx += ecc) {
- ecc_status = chip->ecc.correct(mtd, &data_poi[datidx], &ecc_code[j], &ecc_calc[j]);
-
- /* Get next chunk of ecc bytes */
- j += eccbytes;
-
- /* Check, if we have a fs supplied oob-buffer,
- * This is the legacy mode. Used by YAFFS1
- * Should go away some day
- */
- if (oob_buf && oobsel->useecc == MTD_NANDECC_PLACE) {
- int *p = (int *)(&oob_data[mtd->oobsize]);
- p[i] = ecc_status;
- }
-
- if ((ecc_status == -1) || (ecc_status > (flags && 0xff))) {
- DEBUG(MTD_DEBUG_LEVEL0, "nand_read_ecc: " "Failed ECC read, page 0x%08x\n", page);
- ecc_failed++;
- }
- }
-
- readoob:
- /* check, if we have a fs supplied oob-buffer */
- if (oob_buf) {
- /* without autoplace. Legacy mode used by YAFFS1 */
- switch (oobsel->useecc) {
- case MTD_NANDECC_AUTOPLACE:
- case MTD_NANDECC_AUTOPL_USR:
- /* Walk through the autoplace chunks */
- for (i = 0; oobsel->oobfree[i][1]; i++) {
- int from = oobsel->oobfree[i][0];
- int num = oobsel->oobfree[i][1];
- memcpy(&oob_buf[oob], &oob_data[from], num);
- oob += num;
- }
- break;
- case MTD_NANDECC_PLACE:
- /* YAFFS1 legacy mode */
- oob_data += chip->ecc.steps * sizeof(int);
- default:
- oob_data += mtd->oobsize;
- }
- }
- readdata:
- /* Partial page read, transfer data into fs buffer */
- if (!aligned) {
- for (j = col; j < end && read < len; j++)
- buf[read++] = data_poi[j];
- chip->pagebuf = realpage;
} else
- read += mtd->writesize;
+ memcpy(buf, chip->data_buf + col, bytes);
- /* Apply delay or wait for ready/busy pin
- * Do this before the AUTOINCR check, so no problems
- * arise if a chip which does auto increment
- * is marked as NOAUTOINCR by the board driver.
- */
- if (!chip->dev_ready)
- udelay(chip->chip_delay);
- else
- nand_wait_ready(mtd);
+ buf += bytes;
+ readlen -= bytes;
- if (read == len)
+ if (!readlen)
break;
/* For subsequent reads align to page boundary. */
@@ -1240,24 +1208,51 @@
chip->select_chip(mtd, -1);
chip->select_chip(mtd, chipnr);
}
+
/* Check, if the chip supports auto page increment
* or if we have hit a block boundary.
*/
- if (!NAND_CANAUTOINCR(chip) || !(page & blockcheck))
+ if (!NAND_CANAUTOINCR(chip) || !(page & blkcheck))
sndcmd = 1;
}
- /* Deselect and wake up anyone waiting on the device */
- if (flags & NAND_GET_DEVICE)
- nand_release_device(mtd);
+ *retlen = len - (size_t) readlen;
- /*
- * Return success, if no ECC failures, else -EBADMSG
- * fs driver will take care of that, because
- * retlen == desired len and result == -EBADMSG
- */
- *retlen = read;
- return ecc_failed ? -EBADMSG : 0;
+ if (ret)
+ return ret;
+
+ return mtd->ecc_stats.failed - stats.failed ? -EBADMSG : 0;
+}
+
+/**
+ * nand_read - [MTD Interface] MTD compability function for nand_do_read_ecc
+ * @mtd: MTD device structure
+ * @from: offset to read from
+ * @len: number of bytes to read
+ * @retlen: pointer to variable to store the number of read bytes
+ * @buf: the databuffer to put data
+ *
+ * Get hold of the chip and call nand_do_read
+ */
+static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, uint8_t *buf)
+{
+ int ret;
+
+ *retlen = 0;
+ /* Do not allow reads past end of device */
+ if ((from + len) > mtd->size)
+ return -EINVAL;
+ if (!len)
+ return 0;
+
+ nand_get_device(mtd->priv, mtd, FL_READING);
+
+ ret = nand_do_read(mtd, from, len, retlen, buf);
+
+ nand_release_device(mtd);
+
+ return ret;
}
/**
@@ -2417,6 +2412,10 @@
*/
switch (chip->ecc.mode) {
case NAND_ECC_HW:
+ /* Use standard hwecc read page function ? */
+ if (!chip->ecc.read_page)
+ chip->ecc.read_page = nand_read_page_hwecc;
+
case NAND_ECC_HW_SYNDROME:
if (!chip->ecc.calculate || !chip->ecc.correct ||
!chip->ecc.hwctl) {
@@ -2424,6 +2423,10 @@
"Hardware ECC not possible\n");
BUG();
}
+ /* Use standard syndrome read page function ? */
+ if (!chip->ecc.read_page)
+ chip->ecc.read_page = nand_read_page_syndrome;
+
if (mtd->writesize >= chip->ecc.size)
break;
printk(KERN_WARNING "%d byte HW ECC not possible on "
@@ -2434,6 +2437,7 @@
case NAND_ECC_SOFT:
chip->ecc.calculate = nand_calculate_ecc;
chip->ecc.correct = nand_correct_data;
+ chip->ecc.read_page = nand_read_page_swecc;
chip->ecc.size = 256;
chip->ecc.bytes = 3;
break;
@@ -2441,6 +2445,7 @@
case NAND_ECC_NONE:
printk(KERN_WARNING "NAND_ECC_NONE selected by board driver. "
"This is not recommended !!\n");
+ chip->ecc.read_page = nand_read_page_swecc;
chip->ecc.size = mtd->writesize;
chip->ecc.bytes = 0;
break;
@@ -2459,6 +2464,7 @@
printk(KERN_WARNING "Invalid ecc parameters\n");
BUG();
}
+ chip->ecc.total = chip->ecc.steps * chip->ecc.bytes;
/* Initialize state */
chip->state = FL_READY;