This is a note to let you know that I've just added the patch titled
bus: ixp4xx: Don't touch bit 7 on IXP42x
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bus-ixp4xx-don-t-touch-bit-7-on-ixp42x.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ff5a19909b49fe5c0b01ae197f84b741e0f698dc Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
Date: Tue, 22 Nov 2022 14:44:11 +0100
Subject: bus: ixp4xx: Don't touch bit 7 on IXP42x
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
commit ff5a19909b49fe5c0b01ae197f84b741e0f698dc upstream.
We face some regressions on a few IXP42x systems when
accessing flash, the following unrelated error prints
appear from the PCI driver:
ixp4xx-pci c0000000.pci: PCI: abort_handler addr = 0xff9ffb5f,
isr = 0x0, status = 0x22a0
ixp4xx-pci c0000000.pci: imprecise abort
(...)
It turns out that while bit 7 is masked "reserved" it is
not unused, so masking it off as zero is dangerous, and
breaks flash access on some systems such as the NSLU2.
Be more careful and avoid masking off any of the reserved
bits 7, 8, 9 or 30. Only keep masking EXP_WORD (bit 2)
on IXP43x which is necessary in some setups.
Fixes: 1c953bda90ca ("bus: ixp4xx: Add a driver for IXP4xx expansion bus")
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20221122134411.2030372-1-linus.walleij@xxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/bus/intel-ixp4xx-eb.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/bus/intel-ixp4xx-eb.c b/drivers/bus/intel-ixp4xx-eb.c
index a4388440aca7..91db001eb69a 100644
--- a/drivers/bus/intel-ixp4xx-eb.c
+++ b/drivers/bus/intel-ixp4xx-eb.c
@@ -49,7 +49,7 @@
#define IXP4XX_EXP_SIZE_SHIFT 10
#define IXP4XX_EXP_CNFG_0 BIT(9) /* Always zero */
#define IXP43X_EXP_SYNC_INTEL BIT(8) /* Only on IXP43x */
-#define IXP43X_EXP_EXP_CHIP BIT(7) /* Only on IXP43x */
+#define IXP43X_EXP_EXP_CHIP BIT(7) /* Only on IXP43x, dangerous to touch on IXP42x */
#define IXP4XX_EXP_BYTE_RD16 BIT(6)
#define IXP4XX_EXP_HRDY_POL BIT(5) /* Only on IXP42x */
#define IXP4XX_EXP_MUX_EN BIT(4)
@@ -57,8 +57,6 @@
#define IXP4XX_EXP_WORD BIT(2) /* Always zero */
#define IXP4XX_EXP_WR_EN BIT(1)
#define IXP4XX_EXP_BYTE_EN BIT(0)
-#define IXP42X_RESERVED (BIT(30)|IXP4XX_EXP_CNFG_0|BIT(8)|BIT(7)|IXP4XX_EXP_WORD)
-#define IXP43X_RESERVED (BIT(30)|IXP4XX_EXP_CNFG_0|BIT(5)|IXP4XX_EXP_WORD)
#define IXP4XX_EXP_CNFG0 0x20
#define IXP4XX_EXP_CNFG0_MEM_MAP BIT(31)
@@ -252,10 +250,9 @@ static void ixp4xx_exp_setup_chipselect(struct ixp4xx_eb *eb,
cs_cfg |= val << IXP4XX_EXP_CYC_TYPE_SHIFT;
}
- if (eb->is_42x)
- cs_cfg &= ~IXP42X_RESERVED;
if (eb->is_43x) {
- cs_cfg &= ~IXP43X_RESERVED;
+ /* Should always be zero */
+ cs_cfg &= ~IXP4XX_EXP_WORD;
/*
* This bit for Intel strata flash is currently unused, but let's
* report it if we find one.
--
2.38.1
Patches currently in stable-queue which might be from linus.walleij@xxxxxxxxxx are
queue-5.15/bus-ixp4xx-don-t-touch-bit-7-on-ixp42x.patch
