mtd: msm_nand: Support for partial page read and multi page write
Linux UBI (Unsorted Block Images) driver is a volume management system
for raw flash devices. It makes use of MTD character device interface,
and it allows having UBIFS (UBI filesystem) on top of it.
The current msm nand driver doesn't support partial page read
and multi page write of vmalloc'ed data buffer which is needed by
UBI driver. Add support for these in low level nand driver.
Change-Id: Ibe47116b1b8c9e58f8703f62710ff5926eb8b6dc
Acked-by: Ho Lee <holee@qualcomm.com>
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
diff --git a/drivers/mtd/devices/msm_nand.c b/drivers/mtd/devices/msm_nand.c
index bd36aea..c43abca 100644
--- a/drivers/mtd/devices/msm_nand.c
+++ b/drivers/mtd/devices/msm_nand.c
@@ -1990,20 +1990,74 @@
{
int ret;
struct mtd_oob_ops ops;
+ int (*read_oob)(struct mtd_info *, loff_t, struct mtd_oob_ops *);
- /* printk("msm_nand_read %llx %x\n", from, len); */
+ if (!dual_nand_ctlr_present)
+ read_oob = msm_nand_read_oob;
+ else
+ read_oob = msm_nand_read_oob_dualnandc;
ops.mode = MTD_OPS_PLACE_OOB;
- ops.len = len;
ops.retlen = 0;
ops.ooblen = 0;
- ops.datbuf = buf;
ops.oobbuf = NULL;
- if (!dual_nand_ctlr_present)
- ret = msm_nand_read_oob(mtd, from, &ops);
- else
- ret = msm_nand_read_oob_dualnandc(mtd, from, &ops);
- *retlen = ops.retlen;
+ ret = 0;
+ *retlen = 0;
+
+ if ((from & (mtd->writesize - 1)) == 0 && len == mtd->writesize) {
+ /* reading a page on page boundary */
+ ops.len = len;
+ ops.datbuf = buf;
+ ret = read_oob(mtd, from, &ops);
+ *retlen = ops.retlen;
+ } else if (len > 0) {
+ /* reading any size on any offset. partial page is supported */
+ u8 *bounce_buf;
+ loff_t aligned_from;
+ loff_t offset;
+ size_t actual_len;
+
+ bounce_buf = kmalloc(mtd->writesize, GFP_KERNEL);
+ if (!bounce_buf) {
+ pr_err("%s: could not allocate memory\n", __func__);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ops.len = mtd->writesize;
+ offset = from & (mtd->writesize - 1);
+ aligned_from = from - offset;
+
+ for (;;) {
+ int no_copy;
+
+ actual_len = mtd->writesize - offset;
+ if (actual_len > len)
+ actual_len = len;
+
+ no_copy = (offset == 0 && actual_len == mtd->writesize);
+ ops.datbuf = (no_copy) ? buf : bounce_buf;
+ ret = read_oob(mtd, aligned_from, &ops);
+ if (ret < 0)
+ break;
+
+ if (!no_copy)
+ memcpy(buf, bounce_buf + offset, actual_len);
+
+ len -= actual_len;
+ *retlen += actual_len;
+ if (len == 0)
+ break;
+
+ buf += actual_len;
+ offset = 0;
+ aligned_from += mtd->writesize;
+ }
+
+ kfree(bounce_buf);
+ }
+
+out:
return ret;
}
@@ -2963,18 +3017,54 @@
{
int ret;
struct mtd_oob_ops ops;
+ int (*write_oob)(struct mtd_info *, loff_t, struct mtd_oob_ops *);
+
+ if (!dual_nand_ctlr_present)
+ write_oob = msm_nand_write_oob;
+ else
+ write_oob = msm_nand_write_oob_dualnandc;
ops.mode = MTD_OPS_PLACE_OOB;
- ops.len = len;
ops.retlen = 0;
ops.ooblen = 0;
- ops.datbuf = (uint8_t *)buf;
ops.oobbuf = NULL;
- if (!dual_nand_ctlr_present)
- ret = msm_nand_write_oob(mtd, to, &ops);
- else
- ret = msm_nand_write_oob_dualnandc(mtd, to, &ops);
- *retlen = ops.retlen;
+ ret = 0;
+ *retlen = 0;
+
+ if (!virt_addr_valid(buf) &&
+ ((to | len) & (mtd->writesize - 1)) == 0 &&
+ ((unsigned long) buf & ~PAGE_MASK) + len > PAGE_SIZE) {
+ /*
+ * Handle writing of large size write buffer in vmalloc
+ * address space that does not fit in an MMU page.
+ * The destination address must be on page boundary,
+ * and the size must be multiple of NAND page size.
+ * Writing partial page is not supported.
+ */
+ ops.len = mtd->writesize;
+
+ for (;;) {
+ ops.datbuf = (uint8_t *) buf;
+
+ ret = write_oob(mtd, to, &ops);
+ if (ret < 0)
+ break;
+
+ len -= mtd->writesize;
+ *retlen += mtd->writesize;
+ if (len == 0)
+ break;
+
+ buf += mtd->writesize;
+ to += mtd->writesize;
+ }
+ } else {
+ ops.len = len;
+ ops.datbuf = (uint8_t *) buf;
+ ret = write_oob(mtd, to, &ops);
+ *retlen = ops.retlen;
+ }
+
return ret;
}
@@ -6747,6 +6837,7 @@
mtd->writesize = supported_flash.pagesize * i;
mtd->oobsize = supported_flash.oobsize * i;
mtd->erasesize = supported_flash.blksize * i;
+ mtd->writebufsize = mtd->writesize;
if (!interleave_enable)
mtd_writesize = mtd->writesize;