From 2a027b47dba6b77ab8c8e47b589ae9bbc5ac6175 Mon Sep 17 00:00:00 2001
From: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Date: Sun, 3 Jun 2018 23:02:01 +0900
Subject: [PATCH] MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum
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The erratum and workaround are described by BCM5300X-ES300-RDS.pdf as
below.
R10: PCIe Transactions Periodically Fail
Description: The BCM5300X PCIe does not maintain transaction ordering.
This may cause PCIe transaction failure.
Fix Comment: Add a dummy PCIe configuration read after a PCIe
configuration write to ensure PCIe configuration access
ordering. Set ES bit of CP0 configu7 register to enable
sync function so that the sync instruction is functional.
Resolution: hndpci.c: extpci_write_config()
hndmips.c: si_mips_init()
mipsinc.h CONF7_ES
This is fixed by the CFE MIPS bcmsi chipset driver also for BCM47XX.
Also the dummy PCIe configuration read is already implemented in the
Linux BCMA driver.
Enable ExternalSync in Config7 when CONFIG_BCMA_DRIVER_PCI_HOSTMODE=y
too so that the sync instruction is externalised.
Signed-off-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/19461/
Signed-off-by: James Hogan <jhogan@kernel.org>
---
arch/mips/bcm47xx/setup.c | 6 ++++++
arch/mips/include/asm/mipsregs.h | 3 +++
2 files changed, 9 insertions(+)
diff --git a/arch/mips/bcm47xx/setup.c b/arch/mips/bcm47xx/setup.c
index 6054d49e608ee..8c9cbf13d32a0 100644
--- a/arch/mips/bcm47xx/setup.c
+++ b/arch/mips/bcm47xx/setup.c
@@ -212,6 +212,12 @@ static int __init bcm47xx_cpu_fixes(void)
*/
if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
cpu_wait = NULL;
+
+ /*
+ * BCM47XX Erratum "R10: PCIe Transactions Periodically Fail"
+ * Enable ExternalSync for sync instruction to take effect
+ */
+ set_c0_config7(MIPS_CONF7_ES);
break;
#endif
}
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index ae461d91cd1fa..0bc270806ec5a 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -681,6 +681,8 @@
#define MIPS_CONF7_WII (_ULCAST_(1) << 31)
#define MIPS_CONF7_RPS (_ULCAST_(1) << 2)
+/* ExternalSync */
+#define MIPS_CONF7_ES (_ULCAST_(1) << 8)
#define MIPS_CONF7_IAR (_ULCAST_(1) << 10)
#define MIPS_CONF7_AR (_ULCAST_(1) << 16)
@@ -2765,6 +2767,7 @@ __BUILD_SET_C0(status)
__BUILD_SET_C0(cause)
__BUILD_SET_C0(config)
__BUILD_SET_C0(config5)
+__BUILD_SET_C0(config7)
__BUILD_SET_C0(intcontrol)
__BUILD_SET_C0(intctl)
__BUILD_SET_C0(srsmap)
--
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