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-rw-r--r--target/linux/sunxi/patches-4.1/113-mtd-nand-add-pst.patch261
1 files changed, 261 insertions, 0 deletions
diff --git a/target/linux/sunxi/patches-4.1/113-mtd-nand-add-pst.patch b/target/linux/sunxi/patches-4.1/113-mtd-nand-add-pst.patch
new file mode 100644
index 0000000..45b9679
--- /dev/null
+++ b/target/linux/sunxi/patches-4.1/113-mtd-nand-add-pst.patch
@@ -0,0 +1,261 @@
+From bec69bb8e85151729014d859106dcc3fe652b1d4 Mon Sep 17 00:00:00 2001
+From: Boris BREZILLON <boris.brezillon@free-electrons.com>
+Date: Mon, 28 Jul 2014 14:45:40 +0200
+Subject: [PATCH] mtd: nand: Add page status table (pst)
+
+Page status table is an byte array storing pages status.
+It defines 3 status:
+ - unknown: the page has not been read yet and we do not know its current
+ state
+ - empty: the page contains only FFs
+ - filled: the page has been filled with data
+
+Care must be taken: an empty page does not mean it can be written, because
+it might have already been written with only FFs.
+
+These page status are useful to check wether the controller should try to
+correct errors (using ECC) or a derandomize data (using a randomizer
+block).
+
+Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
+Signed-off-by: Hans de Goede <hdegoede@redhat.com>
+---
+ drivers/mtd/nand/nand_base.c | 154 +++++++++++++++++++++++++++++++++++++++++++
+ include/linux/mtd/nand.h | 21 ++++++
+ 2 files changed, 175 insertions(+)
+
+--- a/drivers/mtd/nand/nand_base.c
++++ b/drivers/mtd/nand/nand_base.c
+@@ -1102,6 +1102,138 @@ out:
+ EXPORT_SYMBOL(nand_lock);
+
+ /**
++ * nand_page_is_empty - check wether a NAND page contains only FFs
++ * @mtd: mtd info
++ * @data: data buffer
++ * @oob: oob buffer
++ *
++ * Reads the data stored in the databuf buffer and check if it contains only
++ * FFs.
++ *
++ * Return true if it does else return false.
++ */
++bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob)
++{
++ u8 *buf;
++ int length;
++ u32 pattern = 0xffffffff;
++ int bitflips = 0;
++ int cnt;
++
++ buf = data;
++ length = mtd->writesize;
++ while (length) {
++ cnt = length < sizeof(pattern) ? length : sizeof(pattern);
++ if (memcmp(&pattern, buf, cnt)) {
++ int i;
++ for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
++ if (!(buf[i / BITS_PER_BYTE] &
++ (1 << (i % BITS_PER_BYTE)))) {
++ bitflips++;
++ if (bitflips > mtd->ecc_strength)
++ return false;
++ }
++ }
++ }
++
++ buf += sizeof(pattern);
++ length -= sizeof(pattern);
++ }
++
++ buf = oob;
++ length = mtd->oobsize;
++ while (length) {
++ cnt = length < sizeof(pattern) ? length : sizeof(pattern);
++ if (memcmp(&pattern, buf, cnt)) {
++ int i;
++ for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
++ if (!(buf[i / BITS_PER_BYTE] &
++ (1 << (i % BITS_PER_BYTE)))) {
++ bitflips++;
++ if (bitflips > mtd->ecc_strength)
++ return false;
++ }
++ }
++ }
++
++ buf += sizeof(pattern);
++ length -= sizeof(pattern);
++ }
++
++ return true;
++}
++EXPORT_SYMBOL(nand_page_is_empty);
++
++/**
++ * nand_page_get_status - retrieve page status from the page status table (pst)
++ * @mtd: mtd info
++ * @page: page you want to get status on
++ *
++ * Return the page status.
++ */
++int nand_page_get_status(struct mtd_info *mtd, int page)
++{
++ struct nand_chip *chip = mtd->priv;
++ u8 shift = (page % 4) * 2;
++ uint64_t offset = page / 4;
++ int ret = NAND_PAGE_STATUS_UNKNOWN;
++
++ if (chip->pst)
++ ret = (chip->pst[offset] >> shift) & 0x3;
++
++ return ret;
++}
++EXPORT_SYMBOL(nand_page_get_status);
++
++/**
++ * nand_page_set_status - assign page status from in the page status table
++ * @mtd: mtd info
++ * @page: page you want to get status on
++ * @status: new status to assign
++ */
++void nand_page_set_status(struct mtd_info *mtd, int page,
++ enum nand_page_status status)
++{
++ struct nand_chip *chip = mtd->priv;
++ u8 shift;
++ uint64_t offset;
++
++ if (!chip->pst)
++ return;
++
++ shift = (page % 4) * 2;
++ offset = page / 4;
++ chip->pst[offset] &= ~(0x3 << shift);
++ chip->pst[offset] |= (status & 0x3) << shift;
++}
++EXPORT_SYMBOL(nand_page_set_status);
++
++/**
++ * nand_pst_create - create a page status table
++ * @mtd: mtd info
++ *
++ * Allocate a page status table and assign it to the mtd device.
++ *
++ * Returns 0 in case of success or -ERRNO in case of error.
++ */
++int nand_pst_create(struct mtd_info *mtd)
++{
++ struct nand_chip *chip = mtd->priv;
++
++ if (chip->pst)
++ return 0;
++
++ chip->pst = kzalloc(mtd->size >>
++ (chip->page_shift + mtd->subpage_sft + 2),
++ GFP_KERNEL);
++ if (!chip->pst)
++ return -ENOMEM;
++
++ return 0;
++}
++EXPORT_SYMBOL(nand_pst_create);
++
++/**
+ * nand_read_page_raw - [INTERN] read raw page data without ecc
+ * @mtd: mtd info structure
+ * @chip: nand chip info structure
+@@ -2539,6 +2671,7 @@ static int nand_do_write_ops(struct mtd_
+ uint8_t *wbuf = buf;
+ int use_bufpoi;
+ int part_pagewr = (column || writelen < (mtd->writesize - 1));
++ int subpage;
+
+ if (part_pagewr)
+ use_bufpoi = 1;
+@@ -2574,6 +2707,14 @@ static int nand_do_write_ops(struct mtd_
+ if (ret)
+ break;
+
++ for (subpage = column / chip->subpagesize;
++ subpage < (column + writelen) / chip->subpagesize;
++ subpage++)
++ nand_page_set_status(mtd,
++ (page << mtd->subpage_sft) +
++ subpage,
++ NAND_PAGE_FILLED);
++
+ writelen -= bytes;
+ if (!writelen)
+ break;
+@@ -2979,6 +3120,7 @@ int nand_erase_nand(struct mtd_info *mtd
+ int page, status, pages_per_block, ret, chipnr;
+ struct nand_chip *chip = mtd->priv;
+ loff_t len;
++ int i;
+
+ pr_debug("%s: start = 0x%012llx, len = %llu\n",
+ __func__, (unsigned long long)instr->addr,
+@@ -3051,6 +3193,18 @@ int nand_erase_nand(struct mtd_info *mtd
+ goto erase_exit;
+ }
+
++ for (i = 0; i < pages_per_block; i++) {
++ int subpage;
++ for (subpage = 0;
++ subpage < 1 << mtd->subpage_sft;
++ subpage++) {
++ nand_page_set_status(mtd,
++ ((page + i) << mtd->subpage_sft) +
++ subpage,
++ NAND_PAGE_EMPTY);
++ }
++ }
++
+ /* Increment page address and decrement length */
+ len -= (1ULL << chip->phys_erase_shift);
+ page += pages_per_block;
+--- a/include/linux/mtd/nand.h
++++ b/include/linux/mtd/nand.h
+@@ -521,6 +521,24 @@ struct nand_ecc_ctrl {
+ int page);
+ };
+
++/*
++ * Constants for page status
++ */
++enum nand_page_status {
++ NAND_PAGE_STATUS_UNKNOWN,
++ NAND_PAGE_EMPTY,
++ NAND_PAGE_FILLED,
++};
++
++bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob);
++
++int nand_page_get_status(struct mtd_info *mtd, int page);
++
++void nand_page_set_status(struct mtd_info *mtd, int page,
++ enum nand_page_status status);
++
++int nand_pst_create(struct mtd_info *mtd);
++
+ /**
+ * struct nand_buffers - buffer structure for read/write
+ * @ecccalc: buffer pointer for calculated ECC, size is oobsize.
+@@ -630,6 +648,7 @@ struct nand_buffers {
+ * @bbt_md: [REPLACEABLE] bad block table mirror descriptor
+ * @badblock_pattern: [REPLACEABLE] bad block scan pattern used for initial
+ * bad block scan.
++ * @pst: [INTERN] page status table
+ * @controller: [REPLACEABLE] a pointer to a hardware controller
+ * structure which is shared among multiple independent
+ * devices.
+@@ -718,6 +737,8 @@ struct nand_chip {
+
+ struct nand_bbt_descr *badblock_pattern;
+
++ uint8_t *pst;
++
+ struct list_head partitions;
+ struct mutex part_lock;
+
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