[OpenWrt-Devel] [PATCH] generic: spi-nor: rework broken-flash-reset
Chuanhong Guo
gch981213 at gmail.com
Mon Apr 6 07:44:28 EDT 2020
Instead of resetting flash to 3B address on remove hook, this
implementation only enters 4B mode when needed, which prevents more
unexpected reboot stuck. This implementation makes it only break when
a kernel panic happens during flash operation on 16M+ areas.
Also silent broken-flash-reset warning. We are not dealing with vendors
and it's unpleasant for users to see that unnecessary and long WARN_ON
print.
Signed-off-by: Chuanhong Guo <gch981213 at gmail.com>
---
This patch is inspired by previous work from:
target/linux/ramips/patches-4.14/0053-mtd-spi-nor-add-w25q256-3b-mode-switch.patch
I was initially porting this patch to 5.4 for w25q256 rebooting issue,
but later realized that this read_op implementation is just two lines
away from a better broken-flash-reset support. I then chose to do this
because:
1. comparing to w25q256 4b_read_op, this only loss the ability to recover
from panic during flash read on >16M region.
2. broken-flash-reset is needed for devices with mx25l25635e anyway.
...or-rework-broken-flash-reset-support.patch | 167 ++++++++++++++++++
.../302-spi-nor-add-gd25q512.patch | 2 +-
2 files changed, 168 insertions(+), 1 deletion(-)
create mode 100644 target/linux/generic/pending-5.4/481-mtd-spi-nor-rework-broken-flash-reset-support.patch
diff --git a/target/linux/generic/pending-5.4/481-mtd-spi-nor-rework-broken-flash-reset-support.patch b/target/linux/generic/pending-5.4/481-mtd-spi-nor-rework-broken-flash-reset-support.patch
new file mode 100644
index 0000000000..b2f73a5cbd
--- /dev/null
+++ b/target/linux/generic/pending-5.4/481-mtd-spi-nor-rework-broken-flash-reset-support.patch
@@ -0,0 +1,167 @@
+From ea92cbb50a78404e29de2cc3999a240615ffb1c8 Mon Sep 17 00:00:00 2001
+From: Chuanhong Guo <gch981213 at gmail.com>
+Date: Mon, 6 Apr 2020 17:58:48 +0800
+Subject: [PATCH] mtd: spi-nor: rework broken-flash-reset support
+
+Instead of resetting flash to 3B address on remove hook, this
+implementation only enters 4B mode when needed, which prevents
+more unexpected reboot stuck. This implementation makes it only
+break when a kernel panic happens during flash operation on 16M+
+areas.
+*OpenWrt only*: silent broken-flash-reset warning. We are not dealing
+with vendors and it's unpleasant for users to se that unnecessary
+and long WARN_ON print.
+
+Signed-off-by: Chuanhong Guo <gch981213 at gmail.com>
+---
+ drivers/mtd/spi-nor/spi-nor.c | 52 +++++++++++++++++++++++++++++++++--
+ 1 file changed, 49 insertions(+), 3 deletions(-)
+
+--- a/drivers/mtd/spi-nor/spi-nor.c
++++ b/drivers/mtd/spi-nor/spi-nor.c
+@@ -616,6 +616,22 @@ static void spi_nor_set_4byte_opcodes(st
+ }
+ }
+
++static int spi_nor_check_set_addr_width(struct spi_nor *nor, loff_t addr)
++{
++ u8 addr_width;
++
++ if ((nor->flags & (SNOR_F_4B_OPCODES | SNOR_F_BROKEN_RESET)) !=
++ SNOR_F_BROKEN_RESET)
++ return 0;
++
++ addr_width = addr & 0xff000000 ? 4 : 3;
++ if (nor->addr_width == addr_width)
++ return 0;
++
++ nor->addr_width = addr_width;
++ return nor->params.set_4byte(nor, addr_width == 4);
++}
++
+ static int macronix_set_4byte(struct spi_nor *nor, bool enable)
+ {
+ if (nor->spimem) {
+@@ -1259,6 +1275,10 @@ static int spi_nor_erase(struct mtd_info
+ if (ret)
+ return ret;
+
++ ret = spi_nor_check_set_addr_width(nor, instr->addr + instr->len);
++ if (ret < 0)
++ return ret;
++
+ /* whole-chip erase? */
+ if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
+ unsigned long timeout;
+@@ -1315,6 +1335,7 @@ static int spi_nor_erase(struct mtd_info
+ write_disable(nor);
+
+ erase_err:
++ spi_nor_check_set_addr_width(nor, 0);
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);
+
+ return ret;
+@@ -1621,7 +1642,9 @@ static int spi_nor_lock(struct mtd_info
+ if (ret)
+ return ret;
+
++ spi_nor_check_set_addr_width(nor, ofs + len);
+ ret = nor->params.locking_ops->lock(nor, ofs, len);
++ spi_nor_check_set_addr_width(nor, 0);
+
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
+ return ret;
+@@ -1636,7 +1659,9 @@ static int spi_nor_unlock(struct mtd_inf
+ if (ret)
+ return ret;
+
++ spi_nor_check_set_addr_width(nor, ofs + len);
+ ret = nor->params.locking_ops->unlock(nor, ofs, len);
++ spi_nor_check_set_addr_width(nor, 0);
+
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
+ return ret;
+@@ -1651,7 +1676,9 @@ static int spi_nor_is_locked(struct mtd_
+ if (ret)
+ return ret;
+
++ spi_nor_check_set_addr_width(nor, ofs + len);
+ ret = nor->params.locking_ops->is_locked(nor, ofs, len);
++ spi_nor_check_set_addr_width(nor, 0);
+
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
+ return ret;
+@@ -2557,6 +2584,10 @@ static int spi_nor_read(struct mtd_info
+ if (ret)
+ return ret;
+
++ ret = spi_nor_check_set_addr_width(nor, from + len);
++ if (ret < 0)
++ return ret;
++
+ while (len) {
+ loff_t addr = from;
+
+@@ -2580,6 +2611,7 @@ static int spi_nor_read(struct mtd_info
+ ret = 0;
+
+ read_err:
++ spi_nor_check_set_addr_width(nor, 0);
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
+ return ret;
+ }
+@@ -2597,6 +2629,10 @@ static int sst_write(struct mtd_info *mt
+ if (ret)
+ return ret;
+
++ ret = spi_nor_check_set_addr_width(nor, to + len);
++ if (ret < 0)
++ return ret;
++
+ write_enable(nor);
+
+ nor->sst_write_second = false;
+@@ -2659,6 +2695,7 @@ static int sst_write(struct mtd_info *mt
+ }
+ sst_write_err:
+ *retlen += actual;
++ spi_nor_check_set_addr_width(nor, 0);
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
+ return ret;
+ }
+@@ -2681,6 +2718,10 @@ static int spi_nor_write(struct mtd_info
+ if (ret)
+ return ret;
+
++ ret = spi_nor_check_set_addr_width(nor, to + len);
++ if (ret < 0)
++ return ret;
++
+ for (i = 0; i < len; ) {
+ ssize_t written;
+ loff_t addr = to + i;
+@@ -2720,6 +2761,7 @@ static int spi_nor_write(struct mtd_info
+ }
+
+ write_err:
++ spi_nor_check_set_addr_width(nor, 0);
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
+ return ret;
+ }
+@@ -4726,9 +4768,13 @@ static int spi_nor_init(struct spi_nor *
+ * reboots (e.g., crashes). Warn the user (or hopefully, system
+ * designer) that this is bad.
+ */
+- WARN_ONCE(nor->flags & SNOR_F_BROKEN_RESET,
+- "enabling reset hack; may not recover from unexpected reboots\n");
+- nor->params.set_4byte(nor, true);
++ if (nor->flags & SNOR_F_BROKEN_RESET) {
++ dev_warn(nor->dev,
++ "enabling reset hack; may not recover from unexpected reboots\n");
++ nor->addr_width = 3;
++ } else {
++ nor->params.set_4byte(nor, true);
++ }
+ }
+
+ return 0;
diff --git a/target/linux/ramips/patches-5.4/302-spi-nor-add-gd25q512.patch b/target/linux/ramips/patches-5.4/302-spi-nor-add-gd25q512.patch
index 3e229bcc1b..52eeb3545b 100644
--- a/target/linux/ramips/patches-5.4/302-spi-nor-add-gd25q512.patch
+++ b/target/linux/ramips/patches-5.4/302-spi-nor-add-gd25q512.patch
@@ -1,6 +1,6 @@
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
-@@ -2238,6 +2238,11 @@ static const struct flash_info spi_nor_i
+@@ -2265,6 +2265,11 @@ static const struct flash_info spi_nor_i
SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
.fixups = &gd25q256_fixups,
},
--
2.25.1
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