mtd: nand: Add support to use nand_base poi databuf as bounce buffer
nand_base can be passed a kmap()'d buffers from highmem by filesystems like jffs2. This results in failure to map the physical address of the DMA buffer on various contoller driver on different platforms. This change adds a chip option to use preallocated databuf as bounce buffers used in nand_do_read_ops() and nand_do_write_ops(). This allows for specific nand controller driver to set this option as needed. Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
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@ -37,6 +37,7 @@
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/nand.h>
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@ -1500,6 +1501,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
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mtd->oobavail : mtd->oobsize;
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uint8_t *bufpoi, *oob, *buf;
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int use_bufpoi;
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unsigned int max_bitflips = 0;
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int retry_mode = 0;
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bool ecc_fail = false;
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@ -1522,9 +1524,20 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
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bytes = min(mtd->writesize - col, readlen);
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aligned = (bytes == mtd->writesize);
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if (!aligned)
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use_bufpoi = 1;
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else if (chip->options & NAND_USE_BOUNCE_BUFFER)
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use_bufpoi = !virt_addr_valid(buf);
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else
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use_bufpoi = 0;
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/* Is the current page in the buffer? */
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if (realpage != chip->pagebuf || oob) {
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bufpoi = aligned ? buf : chip->buffers->databuf;
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bufpoi = use_bufpoi ? chip->buffers->databuf : buf;
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if (use_bufpoi && aligned)
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pr_debug("%s: using read bounce buffer for buf@%p\n",
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__func__, buf);
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read_retry:
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chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
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@ -1546,7 +1559,7 @@ read_retry:
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ret = chip->ecc.read_page(mtd, chip, bufpoi,
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oob_required, page);
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if (ret < 0) {
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if (!aligned)
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if (use_bufpoi)
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/* Invalidate page cache */
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chip->pagebuf = -1;
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break;
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@ -1555,7 +1568,7 @@ read_retry:
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max_bitflips = max_t(unsigned int, max_bitflips, ret);
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/* Transfer not aligned data */
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if (!aligned) {
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if (use_bufpoi) {
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if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
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!(mtd->ecc_stats.failed - ecc_failures) &&
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(ops->mode != MTD_OPS_RAW)) {
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@ -2375,11 +2388,23 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
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int bytes = mtd->writesize;
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int cached = writelen > bytes && page != blockmask;
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uint8_t *wbuf = buf;
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int use_bufpoi;
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int part_pagewr = (column || writelen < (mtd->writesize - 1));
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/* Partial page write? */
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if (unlikely(column || writelen < (mtd->writesize - 1))) {
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if (part_pagewr)
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use_bufpoi = 1;
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else if (chip->options & NAND_USE_BOUNCE_BUFFER)
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use_bufpoi = !virt_addr_valid(buf);
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else
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use_bufpoi = 0;
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/* Partial page write?, or need to use bounce buffer */
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if (use_bufpoi) {
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pr_debug("%s: using write bounce buffer for buf@%p\n",
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__func__, buf);
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cached = 0;
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bytes = min_t(int, bytes - column, (int) writelen);
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if (part_pagewr)
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bytes = min_t(int, bytes - column, writelen);
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chip->pagebuf = -1;
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memset(chip->buffers->databuf, 0xff, mtd->writesize);
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memcpy(&chip->buffers->databuf[column], buf, bytes);
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@ -175,6 +175,11 @@ typedef enum {
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#define NAND_OWN_BUFFERS 0x00020000
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/* Chip may not exist, so silence any errors in scan */
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#define NAND_SCAN_SILENT_NODEV 0x00040000
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/*
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* This option could be defined by controller drivers to protect against
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* kmap'ed, vmalloc'ed highmem buffers being passed from upper layers
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*/
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#define NAND_USE_BOUNCE_BUFFER 0x00080000
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/*
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* Autodetect nand buswidth with readid/onfi.
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* This suppose the driver will configure the hardware in 8 bits mode
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