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mtd: cfi_cmdset_0001: Support the absence of protection registers

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[ Upstream commit b359ed5184 ]

The flash controller implemented by the Arm Base platform behaves like
the Intel StrataFlash J3 device, but omits several features. In
particular it doesn't implement a protection register, so "Number of
Protection register fields" in the Primary Vendor-Specific Extended
Query, is 0.

The Intel StrataFlash J3 datasheet only lists 1 as a valid value for
NumProtectionFields. It describes the field as:

	"Number of Protection register fields in JEDEC ID space.
	“00h,” indicates that 256 protection bytes are available"

While a value of 0 may arguably not be architecturally valid, the
driver's current behavior is certainly wrong: if NumProtectionFields is
0, read_pri_intelext() adds a negative value to the unsigned extra_size,
and ends up in an infinite loop.

Fix it by ignoring a NumProtectionFields of 0.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Stable-dep-of: 565fe150624e ("mtd: cfi_cmdset_0001: Byte swap OTP info")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jean-Philippe Brucker
2020-04-17 16:23:26 +02:00
committed by Greg Kroah-Hartman
parent 21ad8c1c4f
commit 416dad018e
1 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/mtd/chips/cfi_cmdset_0001.c
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@@ -420,8 +420,9 @@ read_pri_intelext(struct map_info *map, __u16 adr)
extra_size = 0;
/* Protection Register info */
extra_size += (extp->NumProtectionFields - 1) *
sizeof(struct cfi_intelext_otpinfo);
if (extp->NumProtectionFields)
extra_size += (extp->NumProtectionFields - 1) *
sizeof(struct cfi_intelext_otpinfo);
}
if (extp->MinorVersion >= '1') {
@@ -695,14 +696,16 @@ static int cfi_intelext_partition_fixup(struct mtd_info *mtd,
*/
if (extp && extp->MajorVersion == '1' && extp->MinorVersion >= '3'
&& extp->FeatureSupport & (1 << 9)) {
int offs = 0;
struct cfi_private *newcfi;
struct flchip *chip;
struct flchip_shared *shared;
int offs, numregions, numparts, partshift, numvirtchips, i, j;
int numregions, numparts, partshift, numvirtchips, i, j;
/* Protection Register info */
offs = (extp->NumProtectionFields - 1) *
sizeof(struct cfi_intelext_otpinfo);
if (extp->NumProtectionFields)
offs = (extp->NumProtectionFields - 1) *
sizeof(struct cfi_intelext_otpinfo);
/* Burst Read info */
offs += extp->extra[offs+1]+2;