From d556ad4bbe75faf17b239e151a9f003322b2e851 Mon Sep 17 00:00:00 2001 From: Peter Oruba Date: Tue, 15 May 2007 13:59:13 +0200 Subject: [PATCH] PCI: add PCI-X/PCI-Express read control interfaces This patch introduces an interface to read and write PCI-X / PCI-Express maximum read byte count values from PCI config space. There is a second function that returns the maximum _designed_ read byte count, which marks the maximum value for a device, since some drivers try to set MMRBC to the highest allowed value and rely on such a function. Based on patch set by Stephen Hemminger Cc: Stephen Hemminger Signed-off-by: Peter Oruba Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci.c | 160 +++++++++++++++++++++++++++++++++++++++++++ drivers/pci/quirks.c | 16 +++++ include/linux/pci.h | 7 +- 3 files changed, 182 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index fd47ac0c47..1bb879959a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1374,6 +1374,166 @@ pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask) } #endif +/** + * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count + * @dev: PCI device to query + * + * Returns mmrbc: maximum designed memory read count in bytes + * or appropriate error value. + */ +int pcix_get_max_mmrbc(struct pci_dev *dev) +{ + int ret, err, cap; + u32 stat; + + cap = pci_find_capability(dev, PCI_CAP_ID_PCIX); + if (!cap) + return -EINVAL; + + err = pci_read_config_dword(dev, cap + PCI_X_STATUS, &stat); + if (err) + return -EINVAL; + + ret = (stat & PCI_X_STATUS_MAX_READ) >> 12; + + return ret; +} +EXPORT_SYMBOL(pcix_get_max_mmrbc); + +/** + * pcix_get_mmrbc - get PCI-X maximum memory read byte count + * @dev: PCI device to query + * + * Returns mmrbc: maximum memory read count in bytes + * or appropriate error value. + */ +int pcix_get_mmrbc(struct pci_dev *dev) +{ + int ret, cap; + u32 cmd; + + cap = pci_find_capability(dev, PCI_CAP_ID_PCIX); + if (!cap) + return -EINVAL; + + ret = pci_read_config_dword(dev, cap + PCI_X_CMD, &cmd); + if (!ret) + ret = 512 << ((cmd & PCI_X_CMD_MAX_READ) >> 2); + + return ret; +} +EXPORT_SYMBOL(pcix_get_mmrbc); + +/** + * pcix_set_mmrbc - set PCI-X maximum memory read byte count + * @dev: PCI device to query + * @mmrbc: maximum memory read count in bytes + * valid values are 512, 1024, 2048, 4096 + * + * If possible sets maximum memory read byte count, some bridges have erratas + * that prevent this. + */ +int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc) +{ + int cap, err = -EINVAL; + u32 stat, cmd, v, o; + + if (mmrbc < 512 || mmrbc > 4096 || (mmrbc & (mmrbc-1))) + goto out; + + v = ffs(mmrbc) - 10; + + cap = pci_find_capability(dev, PCI_CAP_ID_PCIX); + if (!cap) + goto out; + + err = pci_read_config_dword(dev, cap + PCI_X_STATUS, &stat); + if (err) + goto out; + + if (v > (stat & PCI_X_STATUS_MAX_READ) >> 21) + return -E2BIG; + + err = pci_read_config_dword(dev, cap + PCI_X_CMD, &cmd); + if (err) + goto out; + + o = (cmd & PCI_X_CMD_MAX_READ) >> 2; + if (o != v) { + if (v > o && dev->bus && + (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_MMRBC)) + return -EIO; + + cmd &= ~PCI_X_CMD_MAX_READ; + cmd |= v << 2; + err = pci_write_config_dword(dev, cap + PCI_X_CMD, cmd); + } +out: + return err; +} +EXPORT_SYMBOL(pcix_set_mmrbc); + +/** + * pcie_get_readrq - get PCI Express read request size + * @dev: PCI device to query + * + * Returns maximum memory read request in bytes + * or appropriate error value. + */ +int pcie_get_readrq(struct pci_dev *dev) +{ + int ret, cap; + u16 ctl; + + cap = pci_find_capability(dev, PCI_CAP_ID_EXP); + if (!cap) + return -EINVAL; + + ret = pci_read_config_word(dev, cap + PCI_EXP_DEVCTL, &ctl); + if (!ret) + ret = 128 << ((ctl & PCI_EXP_DEVCTL_READRQ) >> 12); + + return ret; +} +EXPORT_SYMBOL(pcie_get_readrq); + +/** + * pcie_set_readrq - set PCI Express maximum memory read request + * @dev: PCI device to query + * @count: maximum memory read count in bytes + * valid values are 128, 256, 512, 1024, 2048, 4096 + * + * If possible sets maximum read byte count + */ +int pcie_set_readrq(struct pci_dev *dev, int rq) +{ + int cap, err = -EINVAL; + u16 ctl, v; + + if (rq < 128 || rq > 4096 || (rq & (rq-1))) + goto out; + + v = (ffs(rq) - 8) << 12; + + cap = pci_find_capability(dev, PCI_CAP_ID_EXP); + if (!cap) + goto out; + + err = pci_read_config_word(dev, cap + PCI_EXP_DEVCTL, &ctl); + if (err) + goto out; + + if ((ctl & PCI_EXP_DEVCTL_READRQ) != v) { + ctl &= ~PCI_EXP_DEVCTL_READRQ; + ctl |= v; + err = pci_write_config_dword(dev, cap + PCI_EXP_DEVCTL, ctl); + } + +out: + return err; +} +EXPORT_SYMBOL(pcie_set_readrq); + /** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 01d8f8a884..75bd6a8648 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -627,6 +627,22 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8131_BRIDGE, quirk_ DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8131_BRIDGE, quirk_amd_8131_ioapic); #endif /* CONFIG_X86_IO_APIC */ +/* + * Some settings of MMRBC can lead to data corruption so block changes. + * See AMD 8131 HyperTransport PCI-X Tunnel Revision Guide + */ +static void __init quirk_amd_8131_mmrbc(struct pci_dev *dev) +{ + unsigned char revid; + + pci_read_config_byte(dev, PCI_REVISION_ID, &revid); + if (dev->subordinate && revid <= 0x12) { + printk(KERN_INFO "AMD8131 rev %x detected, disabling PCI-X MMRBC\n", + revid); + dev->subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MMRBC; + } +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8131_BRIDGE, quirk_amd_8131_mmrbc); /* * FIXME: it is questionable that quirk_via_acpi diff --git a/include/linux/pci.h b/include/linux/pci.h index 086a0e5a63..ac403d74a2 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -111,7 +111,8 @@ enum pcie_reset_state { typedef unsigned short __bitwise pci_bus_flags_t; enum pci_bus_flags { - PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1, + PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1, + PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2, }; struct pci_cap_saved_state { @@ -549,6 +550,10 @@ void pci_intx(struct pci_dev *dev, int enable); void pci_msi_off(struct pci_dev *dev); int pci_set_dma_mask(struct pci_dev *dev, u64 mask); int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask); +int pcix_get_max_mmrbc(struct pci_dev *dev); +int pcix_get_mmrbc(struct pci_dev *dev); +int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc); +int pcie_set_readrq(struct pci_dev *dev, int rq); void pci_update_resource(struct pci_dev *dev, struct resource *res, int resno); int __must_check pci_assign_resource(struct pci_dev *dev, int i); int __must_check pci_assign_resource_fixed(struct pci_dev *dev, int i); -- 2.20.1