generic: mtd: backport unlock support and asserted fixes for certain Winbond/Spansion flash chips

This patch got lost in the OpenWrt -> LEDE transition and fixes flash
writes on new UBNT PicoStations.

patches/lede/0031-generic-mtd-backport-unlock-support-and-asserted-fixes-for-certain-Winbond-Spansion-flash-chips.patch

@@ -0,0 +1,139 @@
+From: Matthias Schiffer <mschiffer@universe-factory.net>
+Date: Tue, 20 Jun 2017 11:01:27 +0200
+Subject: generic: mtd: backport unlock support and asserted fixes for certain Winbond/Spansion flash chips
+
+diff --git a/target/linux/generic/patches-4.4/049-0001-mtd-spi-nor-wait-until-lock-unlock-operations-are-re.patch b/target/linux/generic/patches-4.4/049-0001-mtd-spi-nor-wait-until-lock-unlock-operations-are-re.patch
+new file mode 100644
+index 0000000000000000000000000000000000000000..c8aafe2ebbf7368f47e8f4d7a24dd5e45583a136
+--- /dev/null
++++ b/target/linux/generic/patches-4.4/049-0001-mtd-spi-nor-wait-until-lock-unlock-operations-are-re.patch
+@@ -0,0 +1,66 @@
++From 32321e950d8a237d7e8f3a9b76220007dfa87544 Mon Sep 17 00:00:00 2001
++Message-Id: <32321e950d8a237d7e8f3a9b76220007dfa87544.1462572686.git.mschiffer@universe-factory.net>
++From: =?UTF-8?q?Ezequiel=20Garc=C3=ADa?= <ezequiel@vanguardiasur.com.ar>
++Date: Mon, 28 Dec 2015 17:54:51 -0300
++Subject: [PATCH] mtd: spi-nor: wait until lock/unlock operations are ready
++
++On Micron and Numonyx devices, the status register write command
++(WRSR), raises a work-in-progress bit (WIP) on the status register.
++The datasheets for these devices specify that while the status
++register write is in progress, the status register WIP bit can still
++be read to check the end of the operation.
++
++This commit adds a wait_till_ready call on lock/unlock operations,
++which is required for Micron and Numonyx but should be harmless for
++others. This is needed to prevent applications from issuing erase or
++program operations before the unlock operation is completed.
++
++Reported-by: Stas Sergeev <stsp@list.ru>
++Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
++Signed-off-by: Brian Norris <computersforpeace@gmail.com>
++---
++ drivers/mtd/spi-nor/spi-nor.c | 12 ++++++++++--
++ 1 file changed, 10 insertions(+), 2 deletions(-)
++
++--- a/drivers/mtd/spi-nor/spi-nor.c
+++++ b/drivers/mtd/spi-nor/spi-nor.c
++@@ -463,6 +463,7 @@ static int stm_lock(struct spi_nor *nor,
++ 	u8 status_old, status_new;
++ 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
++ 	u8 shift = ffs(mask) - 1, pow, val;
+++	int ret;
++ 
++ 	status_old = read_sr(nor);
++ 
++@@ -499,7 +500,10 @@ static int stm_lock(struct spi_nor *nor,
++ 		return -EINVAL;
++ 
++ 	write_enable(nor);
++-	return write_sr(nor, status_new);
+++	ret = write_sr(nor, status_new);
+++	if (ret)
+++		return ret;
+++	return spi_nor_wait_till_ready(nor);
++ }
++ 
++ /*
++@@ -513,6 +517,7 @@ static int stm_unlock(struct spi_nor *no
++ 	uint8_t status_old, status_new;
++ 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
++ 	u8 shift = ffs(mask) - 1, pow, val;
+++	int ret;
++ 
++ 	status_old = read_sr(nor);
++ 
++@@ -547,7 +552,10 @@ static int stm_unlock(struct spi_nor *no
++ 		return -EINVAL;
++ 
++ 	write_enable(nor);
++-	return write_sr(nor, status_new);
+++	ret = write_sr(nor, status_new);
+++	if (ret)
+++		return ret;
+++	return spi_nor_wait_till_ready(nor);
++ }
++ 
++ /*
+diff --git a/target/linux/generic/patches-4.4/049-0002-mtd-spi-nor-wait-for-SR_WIP-to-clear-on-initial-unlo.patch b/target/linux/generic/patches-4.4/049-0002-mtd-spi-nor-wait-for-SR_WIP-to-clear-on-initial-unlo.patch
+new file mode 100644
+index 0000000000000000000000000000000000000000..0541c95594ec14f62b5db787f4d52d5a42777cdc
+--- /dev/null
++++ b/target/linux/generic/patches-4.4/049-0002-mtd-spi-nor-wait-for-SR_WIP-to-clear-on-initial-unlo.patch
+@@ -0,0 +1,33 @@
++From edf891ef9ab773363f8e58022a26d7d31604aed6 Mon Sep 17 00:00:00 2001
++Message-Id: <edf891ef9ab773363f8e58022a26d7d31604aed6.1462572703.git.mschiffer@universe-factory.net>
++From: Brian Norris <computersforpeace@gmail.com>
++Date: Fri, 29 Jan 2016 11:25:30 -0800
++Subject: [PATCH] mtd: spi-nor: wait for SR_WIP to clear on initial unlock
++
++Fixup a piece leftover by commit 32321e950d8a ("mtd: spi-nor: wait until
++lock/unlock operations are ready"). That commit made us wait for the WIP
++bit to settle after lock/unlock operations, but it missed the open-coded
++"unlock" that happens at probe() time.
++
++We should probably have this code utilize the unlock() routines in the
++future, to avoid duplication, but unfortunately, flash which need to be
++unlocked don't all have a proper ->flash_unlock() callback.
++
++Signed-off-by: Brian Norris <computersforpeace@gmail.com>
++Cc: Stas Sergeev <stsp@users.sourceforge.net>
++Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
++Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
++---
++ drivers/mtd/spi-nor/spi-nor.c | 1 +
++ 1 file changed, 1 insertion(+)
++
++--- a/drivers/mtd/spi-nor/spi-nor.c
+++++ b/drivers/mtd/spi-nor/spi-nor.c
++@@ -1169,6 +1169,7 @@ int spi_nor_scan(struct spi_nor *nor, co
++ 	    info->flags & SPI_NOR_HAS_LOCK) {
++ 		write_enable(nor);
++ 		write_sr(nor, 0);
+++		spi_nor_wait_till_ready(nor);
++ 	}
++ 
++ 	if (!mtd->name)
+diff --git a/target/linux/generic/patches-4.4/466-revert-mtd-spi-nor-fix-Spansion-regressions-aliased-.patch b/target/linux/generic/patches-4.4/466-revert-mtd-spi-nor-fix-Spansion-regressions-aliased-.patch
+new file mode 100644
+index 0000000000000000000000000000000000000000..7c6530a5e0e8bc144e1d4497428e3c3691c2ef22
+--- /dev/null
++++ b/target/linux/generic/patches-4.4/466-revert-mtd-spi-nor-fix-Spansion-regressions-aliased-.patch
+@@ -0,0 +1,18 @@
++--- a/drivers/mtd/spi-nor/spi-nor.c
+++++ b/drivers/mtd/spi-nor/spi-nor.c
++@@ -1161,6 +1161,7 @@ int spi_nor_scan(struct spi_nor *nor, co
++ 	    JEDEC_MFR(info) == SNOR_MFR_INTEL ||
++ 	    JEDEC_MFR(info) == SNOR_MFR_MACRONIX ||
++ 	    JEDEC_MFR(info) == SNOR_MFR_SST ||
+++	    JEDEC_MFR(info) == SNOR_MFR_WINBOND ||
++ 	    info->flags & SPI_NOR_HAS_LOCK) {
++ 		write_enable(nor);
++ 		write_sr(nor, 0);
++@@ -1178,6 +1179,7 @@ int spi_nor_scan(struct spi_nor *nor, co
++ 
++ 	/* NOR protection support for STmicro/Micron chips and similar */
++ 	if (JEDEC_MFR(info) == SNOR_MFR_MICRON ||
+++	    JEDEC_MFR(info) == SNOR_MFR_WINBOND ||
++ 		info->flags & SPI_NOR_HAS_LOCK) {
++ 		nor->flash_lock = stm_lock;
++ 		nor->flash_unlock = stm_unlock;