From 66507c7bc8895f0da6b4ad87e96d61a9f7d7a118 Mon Sep 17 00:00:00 2001 From: Kamal Dasu Date: Thu, 1 May 2014 20:51:19 -0400 Subject: [PATCH] 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 Signed-off-by: Brian Norris --- drivers/mtd/nand/nand_base.c | 37 +++++++++++++++++++++++++++++++------ include/linux/mtd/nand.h | 5 +++++ 2 files changed, 36 insertions(+), 6 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 7853b9b..1b844b8 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -1500,6 +1501,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, mtd->oobavail : mtd->oobsize; uint8_t *bufpoi, *oob, *buf; + int use_bufpoi; unsigned int max_bitflips = 0; int retry_mode = 0; bool ecc_fail = false; @@ -1522,9 +1524,20 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, bytes = min(mtd->writesize - col, readlen); aligned = (bytes == mtd->writesize); + if (!aligned) + use_bufpoi = 1; + else if (chip->options & NAND_USE_BOUNCE_BUFFER) + use_bufpoi = !virt_addr_valid(buf); + else + use_bufpoi = 0; + /* Is the current page in the buffer? */ if (realpage != chip->pagebuf || oob) { - bufpoi = aligned ? buf : chip->buffers->databuf; + bufpoi = use_bufpoi ? chip->buffers->databuf : buf; + + if (use_bufpoi && aligned) + pr_debug("%s: using read bounce buffer for buf@%p\n", + __func__, buf); read_retry: chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); @@ -1546,7 +1559,7 @@ read_retry: ret = chip->ecc.read_page(mtd, chip, bufpoi, oob_required, page); if (ret < 0) { - if (!aligned) + if (use_bufpoi) /* Invalidate page cache */ chip->pagebuf = -1; break; @@ -1555,7 +1568,7 @@ read_retry: max_bitflips = max_t(unsigned int, max_bitflips, ret); /* Transfer not aligned data */ - if (!aligned) { + if (use_bufpoi) { if (!NAND_HAS_SUBPAGE_READ(chip) && !oob && !(mtd->ecc_stats.failed - ecc_failures) && (ops->mode != MTD_OPS_RAW)) { @@ -2375,11 +2388,23 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to, int bytes = mtd->writesize; int cached = writelen > bytes && page != blockmask; uint8_t *wbuf = buf; + int use_bufpoi; + int part_pagewr = (column || writelen < (mtd->writesize - 1)); + + if (part_pagewr) + use_bufpoi = 1; + else if (chip->options & NAND_USE_BOUNCE_BUFFER) + use_bufpoi = !virt_addr_valid(buf); + else + use_bufpoi = 0; - /* Partial page write? */ - if (unlikely(column || writelen < (mtd->writesize - 1))) { + /* Partial page write?, or need to use bounce buffer */ + if (use_bufpoi) { + pr_debug("%s: using write bounce buffer for buf@%p\n", + __func__, buf); cached = 0; - bytes = min_t(int, bytes - column, (int) writelen); + if (part_pagewr) + bytes = min_t(int, bytes - column, writelen); chip->pagebuf = -1; memset(chip->buffers->databuf, 0xff, mtd->writesize); memcpy(&chip->buffers->databuf[column], buf, bytes); diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 7a922e6..2f0af28 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -176,6 +176,11 @@ typedef enum { /* Chip may not exist, so silence any errors in scan */ #define NAND_SCAN_SILENT_NODEV 0x00040000 /* + * This option could be defined by controller drivers to protect against + * kmap'ed, vmalloc'ed highmem buffers being passed from upper layers + */ +#define NAND_USE_BOUNCE_BUFFER 0x00080000 +/* * Autodetect nand buswidth with readid/onfi. * This suppose the driver will configure the hardware in 8 bits mode * when calling nand_scan_ident, and update its configuration -- 2.7.4