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MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum 

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>
This commit is contained in:
Tokunori Ikegami 2018-06-03 23:02:01 +09:00 committed by James Hogan
parent 326345f995
commit 2a027b47db
No known key found for this signature in database
GPG Key ID: 35CEE4862B1023F2
2 changed files with 9 additions and 0 deletions
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6
arch/mips/bcm47xx/setup.c
View File

@ -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
}

3
arch/mips/include/asm/mipsregs.h
View File

@ -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)