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authorRafał Miłecki <rafal@milecki.pl>2016-08-16 22:33:21 +0200
committerRafał Miłecki <rafal@milecki.pl>2016-08-16 22:42:00 +0200
commit2803527237c27bc18a0b9260e1dcbce9dfbbaae5 (patch)
tree7d0a52d97b401a94d51951178c3fb03690b3a9e9 /target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch
parent13e20e6956320bd642314a4e364d5eea584a5849 (diff)
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kernel: add BCM53573 flash fix sent upstream
This fixes flash corruptions. It touches bcm47xxsflash driver shared between brcm47xx and bcm53xx so put it in generic. Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Diffstat (limited to 'target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch')
-rw-r--r--target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch57
1 files changed, 57 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch b/target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch
new file mode 100644
index 0000000000..98c62caf5f
--- /dev/null
+++ b/target/linux/generic/patches-4.4/143-mtd-bcm47xxsflash-use-uncached-MMIO-access-for-BCM53.patch
@@ -0,0 +1,57 @@
+From 77fab8f7dc756ba65f37145c493cc04f17e36bea Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Mon, 15 Aug 2016 14:13:09 +0200
+Subject: [PATCH] mtd: bcm47xxsflash: use uncached MMIO access for BCM53573
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+BCM53573 is a new series of Broadcom's SoCs. It's based on ARM and uses
+this old ChipCommon-based flash access. Early tests resulted in flash
+corruptions that were tracked down to using cached MMIO for flash read
+access. Switch to ioremap_nocache conditionally to support BCM53573 and
+don't break performance on old MIPS devices.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ drivers/mtd/devices/bcm47xxsflash.c | 24 +++++++++++++++++++-----
+ 1 file changed, 19 insertions(+), 5 deletions(-)
+
+--- a/drivers/mtd/devices/bcm47xxsflash.c
++++ b/drivers/mtd/devices/bcm47xxsflash.c
+@@ -296,16 +296,30 @@ static int bcm47xxsflash_bcma_probe(stru
+ dev_err(dev, "can't request region for resource %pR\n", res);
+ return -EBUSY;
+ }
+- b47s->window = ioremap_cache(res->start, resource_size(res));
+- if (!b47s->window) {
+- dev_err(dev, "ioremap failed for resource %pR\n", res);
+- return -ENOMEM;
+- }
+
+ b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
+ b47s->cc_read = bcm47xxsflash_bcma_cc_read;
+ b47s->cc_write = bcm47xxsflash_bcma_cc_write;
+
++ /*
++ * On old MIPS devices cache was magically invalidated when needed,
++ * allowing us to use cached access and gain some performance. Trying
++ * the same on ARM based BCM53573 results in flash corruptions, we need
++ * to use uncached access for it.
++ *
++ * It may be arch specific, but right now there is only 1 ARM SoC using
++ * this driver, so let's follow Broadcom's reference code and check
++ * ChipCommon revision.
++ */
++ if (b47s->bcma_cc->core->id.rev == 54)
++ b47s->window = ioremap_nocache(res->start, resource_size(res));
++ else
++ b47s->window = ioremap_cache(res->start, resource_size(res));
++ if (!b47s->window) {
++ dev_err(dev, "ioremap failed for resource %pR\n", res);
++ return -ENOMEM;
++ }
++
+ switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
+ case BCMA_CC_FLASHT_STSER:
+ b47s->type = BCM47XXSFLASH_TYPE_ST;