diff options
author | Murali Karicheri <m-karicheri2@ti.com> | 2014-09-08 17:03:34 (GMT) |
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committer | Bjorn Helgaas <bhelgaas@google.com> | 2014-09-16 21:31:21 (GMT) |
commit | c15982dfa8227f3e8fd2a6e2e13a009a9991d96c (patch) | |
tree | d4f37a5e49bf0f30f2c7900ffd84433f0b35fc49 /drivers/pci/host | |
parent | 0c4ffcfe1fbc1ef564ec137eab21137cb013b00e (diff) | |
download | linux-c15982dfa8227f3e8fd2a6e2e13a009a9991d96c.tar.xz |
PCI: keystone: Limit MRSS for all downstream devices
Keystone PCIe controller has a limitation that memory read request size
must not exceed 256 bytes. This is a hardware limitation. Add a quirk to
force this limit on all downstream devices by updating MRRS.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/host')
-rw-r--r-- | drivers/pci/host/pci-keystone.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c index c1cfaef..c58a9eb 100644 --- a/drivers/pci/host/pci-keystone.c +++ b/drivers/pci/host/pci-keystone.c @@ -42,8 +42,53 @@ /* DEV_STAT_CTRL */ #define PCIE_CAP_BASE 0x70 +/* PCIE controller device IDs */ +#define PCIE_RC_K2HK 0xb008 +#define PCIE_RC_K2E 0xb009 +#define PCIE_RC_K2L 0xb00a + #define to_keystone_pcie(x) container_of(x, struct keystone_pcie, pp) +static void quirk_limit_mrrs(struct pci_dev *dev) +{ + struct pci_bus *bus = dev->bus; + struct pci_dev *bridge = bus->self; + static const struct pci_device_id rc_pci_devids[] = { + { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2HK), + .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, }, + { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2E), + .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, }, + { PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2L), + .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, }, + { 0, }, + }; + + if (pci_is_root_bus(bus)) + return; + + /* look for the host bridge */ + while (!pci_is_root_bus(bus)) { + bridge = bus->self; + bus = bus->parent; + } + + if (bridge) { + /* + * Keystone PCI controller has a h/w limitation of + * 256 bytes maximum read request size. It can't handle + * anything higher than this. So force this limit on + * all downstream devices. + */ + if (pci_match_id(rc_pci_devids, bridge)) { + if (pcie_get_readrq(dev) > 256) { + dev_info(&dev->dev, "limiting MRRS to 256\n"); + pcie_set_readrq(dev, 256); + } + } + } +} +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, quirk_limit_mrrs); + static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie) { struct pcie_port *pp = &ks_pcie->pp; |