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PCI: dwc: dra7xx: Workaround for errata id i870

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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 <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Kishon Vijay Abraham I 2017-03-27 15:15:11 +05:30 committed by Bjorn Helgaas
parent 40cc72e2b5
commit f7a2757f6c
1 changed files with 49 additions and 0 deletions
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49
drivers/pci/dwc/pci-dra7xx.c
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@ -26,6 +26,8 @@
#include <linux/pm_runtime.h>
#include <linux/resource.h>
#include <linux/types.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include "pcie-designware.h"
@ -528,6 +530,48 @@ static const struct of_device_id of_dra7xx_pcie_match[] = {
{},
};
/*
* dra7xx_pcie_ep_unaligned_memaccess: 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_unaligned_memaccess(struct device *dev)
{
int ret;
struct device_node *np = dev->of_node;
struct of_phandle_args args;
struct regmap *regmap;
regmap = syscon_regmap_lookup_by_phandle(np,
"ti,syscon-unaligned-access");
if (IS_ERR(regmap)) {
dev_dbg(dev, "can't get ti,syscon-unaligned-access\n");
return -EINVAL;
}
ret = of_parse_phandle_with_fixed_args(np, "ti,syscon-unaligned-access",
2, 0, &args);
if (ret) {
dev_err(dev, "failed to parse ti,syscon-unaligned-access\n");
return ret;
}
ret = regmap_update_bits(regmap, args.args[0], args.args[1],
args.args[1]);
if (ret)
dev_err(dev, "failed to enable unaligned access\n");
of_node_put(args.np);
return ret;
}
static int __init dra7xx_pcie_probe(struct platform_device *pdev)
{
u32 reg;
@ -644,6 +688,11 @@ 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_unaligned_memaccess(dev);
if (ret)
goto err_gpio;
ret = dra7xx_add_pcie_ep(dra7xx, pdev);
if (ret < 0)
goto err_gpio;