From c92409812206ac67a7fa7aae298539a9c3804a46 Mon Sep 17 00:00:00 2001 From: Grzegorz Bernacki Date: Tue, 31 Jul 2007 18:51:48 +0200 Subject: [PATCH] [ppc440SPe] Graceful recovery from machine check during PCIe configuration During config transactions on the PCIe bus an attempt to scan for a non-existent device can lead to a machine check exception with certain peripheral devices. In order to avoid crashing in such scenarios the instrumented versions of the config cycle read routines are introduced, so the exceptions fixups framework can gracefully recover. Signed-off-by: Grzegorz Bernacki Acked-by: Rafal Jaworowski --- cpu/ppc4xx/440spe_pcie.c | 36 ++++++++++++++++++++++++++++++++---- cpu/ppc4xx/440spe_pcie.h | 19 +++++++++++++++++-- cpu/ppc4xx/traps.c | 11 ++++++++--- lib_ppc/extable.c | 2 +- 4 files changed, 58 insertions(+), 10 deletions(-) diff --git a/cpu/ppc4xx/440spe_pcie.c b/cpu/ppc4xx/440spe_pcie.c index 7b27e8707a..bf68cc1e96 100644 --- a/cpu/ppc4xx/440spe_pcie.c +++ b/cpu/ppc4xx/440spe_pcie.c @@ -1,5 +1,5 @@ /* - * (C) Copyright 2006 + * (C) Copyright 2006 - 2007 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. * * Copyright (c) 2005 Cisco Systems. All rights reserved. @@ -40,6 +40,34 @@ enum { LNKW_X8 = 0x8 }; +static inline int pcie_in_8(const volatile unsigned char __iomem *addr) +{ + int ret; + + PCIE_IN(lbzx, ret, addr); + + return ret; +} + +static inline int pcie_in_le16(const volatile unsigned short __iomem *addr) +{ + int ret; + + PCIE_IN(lhbrx, ret, addr) + + return ret; +} + +static inline unsigned pcie_in_le32(const volatile unsigned __iomem *addr) +{ + unsigned ret; + + PCIE_IN(lwbrx, ret, addr); + + return ret; +} + + static int pcie_read_config(struct pci_controller *hose, unsigned int devfn, int offset, int len, u32 *val) { @@ -55,13 +83,13 @@ static int pcie_read_config(struct pci_controller *hose, unsigned int devfn, switch (len) { case 1: - *val = in_8(hose->cfg_data + offset); + *val = pcie_in_8(hose->cfg_data + offset); break; case 2: - *val = in_le16((u16 *)(hose->cfg_data + offset)); + *val = pcie_in_le16((u16 *)(hose->cfg_data + offset)); break; default: - *val = in_le32((u32 *)(hose->cfg_data + offset)); + *val = pcie_in_le32((u32*)(hose->cfg_data + offset)); break; } return 0; diff --git a/cpu/ppc4xx/440spe_pcie.h b/cpu/ppc4xx/440spe_pcie.h index 2becc77722..eb7cecf82f 100644 --- a/cpu/ppc4xx/440spe_pcie.h +++ b/cpu/ppc4xx/440spe_pcie.h @@ -145,8 +145,8 @@ #define PECFG_PIMEN 0x33c #define PECFG_PIM0LAL 0x340 #define PECFG_PIM0LAH 0x344 -#define PECFG_PIM1LAL 0x348 -#define PECFG_PIM1LAH 0x34c +#define PECFG_PIM1LAL 0x348 +#define PECFG_PIM1LAH 0x34c #define PECFG_PIM01SAL 0x350 #define PECFG_PIM01SAH 0x354 @@ -161,6 +161,21 @@ mtdcr(DCRN_SDR0_CFGADDR, offset); \ mtdcr(DCRN_SDR0_CFGDATA,data);}) +#define PCIE_IN(opcode, ret, addr) \ + __asm__ __volatile__( \ + "sync\n" \ + #opcode " %0,0,%1\n" \ + "1: twi 0,%0,0\n" \ + "isync\n" \ + "b 3f\n" \ + "2: li %0,-1\n" \ + "3:\n" \ + ".section __ex_table,\"a\"\n" \ + ".balign 4\n" \ + ".long 1b,2b\n" \ + ".previous\n" \ + : "=r" (ret) : "r" (addr), "m" (*addr)); + int ppc440spe_init_pcie(void); int ppc440spe_init_pcie_rootport(int port); void yucca_setup_pcie_fpga_rootpoint(int port); diff --git a/cpu/ppc4xx/traps.c b/cpu/ppc4xx/traps.c index 2fcce3de8b..6b15a9ea28 100755 --- a/cpu/ppc4xx/traps.c +++ b/cpu/ppc4xx/traps.c @@ -151,12 +151,17 @@ MachineCheckException(struct pt_regs *regs) int uncorr_ecc = 0; #endif - /* Probing PCI using config cycles cause this exception - * when a device is not present. Catch it and return to - * the PCI exception handler. + /* Probing PCI(E) using config cycles may cause this exception + * when a device is not present. To gracefully recover in such + * scenarios config read/write routines need to be instrumented in + * order to return via fixup handler. For examples refer to + * pcie_in_8(), pcie_in_le16() and pcie_in_le32() */ if ((fixup = search_exception_table(regs->nip)) != 0) { regs->nip = fixup; + val = mfspr(MCSR); + /* Clear MCSR */ + mtspr(SPRN_MCSR, val); return; } diff --git a/lib_ppc/extable.c b/lib_ppc/extable.c index 8354411f01..2d995fa30a 100644 --- a/lib_ppc/extable.c +++ b/lib_ppc/extable.c @@ -89,7 +89,7 @@ search_exception_table(unsigned long addr) /* if the serial port does not hang in exception, printf can be used */ #if !defined(CFG_SERIAL_HANG_IN_EXCEPTION) if (ex_tab_message) - printf("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret); + debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret); #endif if (ret) return ret; -- 2.39.5