From: Tokunori Ikegami Date: Sun, 3 Jun 2018 14:02:01 +0000 (+0900) Subject: MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum X-Git-Tag: v5.15~8550^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2a027b47dba6b77ab8c8e47b589ae9bbc5ac6175;p=platform%2Fkernel%2Flinux-starfive.git 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 Reviewed-by: Paul Burton Acked-by: Hauke Mehrtens Cc: Chris Packham Cc: Rafał Miłecki Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/19461/ Signed-off-by: James Hogan --- diff --git a/arch/mips/bcm47xx/setup.c b/arch/mips/bcm47xx/setup.c index 6054d49..8c9cbf1 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 ae461d9..0bc2708 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)