From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from devils.ext.ti.com ([198.47.26.153]:33752 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754092AbaIHQ6j (ORCPT ); Mon, 8 Sep 2014 12:58:39 -0400 From: Murali Karicheri To: , , , , CC: Murali Karicheri Subject: [PATCH - v3] PCI: keystone: add a pci quirk to limit mrrs Date: Mon, 8 Sep 2014 12:58:34 -0400 Message-ID: <1410195514-29945-1-git-send-email-m-karicheri2@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-pci-owner@vger.kernel.org List-ID: Keystone PCI controller has a limitation that memory read request size must not exceed 256 bytes. This is a hardware limitation and add a quirk to force this limit on all downstream devices by updating mrrs. Signed-off-by: Murali Karicheri --- -v3: added check for vendor id and use pci_matc_id() to do matching -v2: made the quirk happens after tuning -v1: changed printk to indicate PCI bdf drivers/pci/host/pci-keystone.c | 47 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c index c1cfaef..0a477e5 100644 --- a/drivers/pci/host/pci-keystone.c +++ b/drivers/pci/host/pci-keystone.c @@ -42,8 +42,55 @@ /* 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; -- 1.7.9.5