bcm53xx: use upstream accepted fix for ARM core aborts

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 75 insertions, 0 deletions

diff --git a/target/linux/bcm53xx/patches-4.4/045-ARM-BCM5301X-Add-back-handler-ignoring-external-impr.patch b/target/linux/bcm53xx/patches-4.4/045-ARM-BCM5301X-Add-back-handler-ignoring-external-impr.patch
new file mode 100644
index 0000000..a4f32f5
--- /dev/null
+++ b/target/linux/bcm53xx/patches-4.4/045-ARM-BCM5301X-Add-back-handler-ignoring-external-impr.patch
@@ -0,0 +1,75 @@
+From 09f3510fb70a46c8921f2cf4a90dbcae460a6820 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Sat, 29 Oct 2016 13:12:29 +0200
+Subject: [PATCH] ARM: BCM5301X: Add back handler ignoring external imprecise
+ aborts
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Since early BCM5301X days we got abort handler that was removed by
+commit 937b12306ea79 ("ARM: BCM5301X: remove workaround imprecise abort
+fault handler"). It assumed we need to deal only with pending aborts
+left by the bootloader. Unfortunately this isn't true for BCM5301X.
+
+When probing PCI config space (device enumeration) it is expected to
+have master aborts on the PCI bus. Most bridges don't forward (or they
+allow disabling it) these errors onto the AXI/AMBA bus but not the
+Northstar (BCM5301X) one.
+
+iProc PCIe controller on Northstar seems to be some older one, without
+a control register for errors forwarding. It means we need to workaround
+this at platform level. All newer platforms are not affected by this
+issue.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
+---
+ arch/arm/mach-bcm/bcm_5301x.c | 28 ++++++++++++++++++++++++++++
+ 1 file changed, 28 insertions(+)
+
+--- a/arch/arm/mach-bcm/bcm_5301x.c
++++ b/arch/arm/mach-bcm/bcm_5301x.c
+@@ -9,14 +9,42 @@
+ #include <asm/hardware/cache-l2x0.h>
+ 
+ #include <asm/mach/arch.h>
++#include <asm/siginfo.h>
++#include <asm/signal.h>
++
++#define FSR_EXTERNAL		(1 << 12)
++#define FSR_READ		(0 << 10)
++#define FSR_IMPRECISE		0x0406
+ 
+ static const char *const bcm5301x_dt_compat[] __initconst = {
+ 	"brcm,bcm4708",
+ 	NULL,
+ };
+ 
++static int bcm5301x_abort_handler(unsigned long addr, unsigned int fsr,
++				  struct pt_regs *regs)
++{
++	/*
++	 * We want to ignore aborts forwarded from the PCIe bus that are
++	 * expected and shouldn't really be passed by the PCIe controller.
++	 * The biggest disadvantage is the same FSR code may be reported when
++	 * reading non-existing APB register and we shouldn't ignore that.
++	 */
++	if (fsr == (FSR_EXTERNAL | FSR_READ | FSR_IMPRECISE))
++		return 0;
++
++	return 1;
++}
++
++static void __init bcm5301x_init_early(void)
++{
++	hook_fault_code(16 + 6, bcm5301x_abort_handler, SIGBUS, BUS_OBJERR,
++			"imprecise external abort");
++}
++
+ DT_MACHINE_START(BCM5301X, "BCM5301X")
+ 	.l2c_aux_val	= 0,
+ 	.l2c_aux_mask	= ~0,
+ 	.dt_compat	= bcm5301x_dt_compat,
++	.init_early	= bcm5301x_init_early,
+ MACHINE_END