From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: From: Kishon Vijay Abraham I To: Bjorn Helgaas , Jingoo Han , Joao Pinto Subject: [PATCH v2 13/22] PCI: dwc: dra7xx: Workaround for errata id i870 Date: Fri, 17 Feb 2017 15:20:33 +0530 Message-ID: <1487325042-28227-14-git-send-email-kishon@ti.com> In-Reply-To: <1487325042-28227-1-git-send-email-kishon@ti.com> References: <1487325042-28227-1-git-send-email-kishon@ti.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-pci@vger.kernel.org, nsekhar@ti.com, linux-kernel@vger.kernel.org, Kishon Vijay Abraham I , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: According to errata i870, access to the PCIe slave port that are not 32-bit aligned will result in incorrect mapping to TLP Address and Byte enable fields. Accessing non 32-bit aligned data causes incorrect data in the target buffer if memcpy is used. Implement the workaround for this errata here. Signed-off-by: Kishon Vijay Abraham I --- drivers/pci/dwc/pci-dra7xx.c | 50 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c index 47bb563..df11a49 100644 --- a/drivers/pci/dwc/pci-dra7xx.c +++ b/drivers/pci/dwc/pci-dra7xx.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include #include "pcie-designware.h" @@ -528,6 +530,48 @@ static int dra7xx_pcie_enable_phy(struct dra7xx_pcie *dra7xx) {}, }; +/* + * dra7xx_pcie_ep_legacy_mode: workaround for AM572x/AM571x Errata i870 + * @dra7xx: the dra7xx device where the workaround should be applied + * + * Access to the PCIe slave port that are not 32-bit aligned will result + * in incorrect mapping to TLP Address and Byte enable fields. Therefore, + * byte and half-word accesses are not possible to byte offset 0x1, 0x2, or + * 0x3. + * + * To avoid this issue set PCIE_SS1_AXI2OCP_LEGACY_MODE_ENABLE to 1. + */ +static int dra7xx_pcie_ep_legacy_mode(struct device *dev) +{ + int ret; + struct device_node *np = dev->of_node; + struct regmap *regmap; + unsigned int reg; + unsigned int field; + + regmap = syscon_regmap_lookup_by_phandle(np, "syscon-legacy-mode"); + if (IS_ERR(regmap)) { + dev_dbg(dev, "can't get syscon-legacy-mode\n"); + return -EINVAL; + } + + if (of_property_read_u32_index(np, "syscon-legacy-mode", 1, ®)) { + dev_err(dev, "couldn't get legacy mode register offset\n"); + return -EINVAL; + } + + if (of_property_read_u32_index(np, "syscon-legacy-mode", 2, &field)) { + dev_err(dev, "can't get bit field for setting legacy mode\n"); + return -EINVAL; + } + + ret = regmap_update_bits(regmap, reg, field, field); + if (ret) + dev_err(dev, "failed to set legacy mode\n"); + + return ret; +} + static int __init dra7xx_pcie_probe(struct platform_device *pdev) { u32 reg; @@ -644,6 +688,7 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev) case DW_PCIE_RC_TYPE: dra7xx_pcie_writel(dra7xx, PCIECTRL_TI_CONF_DEVICE_TYPE, DEVICE_TYPE_RC); + ret = dra7xx_add_pcie_port(dra7xx, pdev); if (ret < 0) goto err_gpio; @@ -651,6 +696,11 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev) case DW_PCIE_EP_TYPE: dra7xx_pcie_writel(dra7xx, PCIECTRL_TI_CONF_DEVICE_TYPE, DEVICE_TYPE_EP); + + ret = dra7xx_pcie_ep_legacy_mode(dev); + if (ret) + goto err_gpio; + ret = dra7xx_add_pcie_ep(dra7xx, pdev); if (ret < 0) goto err_gpio; -- 1.7.9.5 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel