Re: [PATCH v2 2/4] pci: dwc: pci-dra7xx: Enable errata i870 for both EP and RC mode

From: Vignesh R
Date: Thu Jul 19 2018 - 06:33:57 EST


Hi Lorenzo,

On Wednesday 18 July 2018 04:32 PM, Lorenzo Pieralisi wrote:
> On Wed, Jun 27, 2018 at 05:59:17PM +0530, Vignesh R wrote:
>> Errata i870 is applicable in both EP and RC mode. Therefore rename
>> function dra7xx_pcie_ep_unaligned_memaccess(), that implements errata
>> workaround, to dra7xx_pcie_unaligned_memaccess() and call it from a
>> common place. So, that errata workaround is applied for both modes of
>> operation.
>>
>> Reported-by: Chris Welch <Chris.Welch@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Vignesh R <vigneshr@xxxxxx>
>> ---
>> drivers/pci/controller/dwc/pci-dra7xx.c | 12 ++++++------
>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
>> index 345aab56ce8b..95d9076e3fde 100644
>> --- a/drivers/pci/controller/dwc/pci-dra7xx.c
>> +++ b/drivers/pci/controller/dwc/pci-dra7xx.c
>> @@ -542,7 +542,7 @@ static const struct of_device_id of_dra7xx_pcie_match[] = {
>> };
>>
>> /*
>> - * dra7xx_pcie_ep_unaligned_memaccess: workaround for AM572x/AM571x Errata i870
>> + * dra7xx_pcie_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
>> @@ -552,7 +552,7 @@ static const struct of_device_id of_dra7xx_pcie_match[] = {
>> *
>> * To avoid this issue set PCIE_SS1_AXI2OCP_LEGACY_MODE_ENABLE to 1.
>> */
>> -static int dra7xx_pcie_ep_unaligned_memaccess(struct device *dev)
>> +static int dra7xx_pcie_unaligned_memaccess(struct device *dev)
>> {
>> int ret;
>> struct device_node *np = dev->of_node;
>> @@ -695,6 +695,10 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
>> if (dra7xx->link_gen < 0 || dra7xx->link_gen > 2)
>> dra7xx->link_gen = 2;
>>
>> + ret = dra7xx_pcie_unaligned_memaccess(dev);
>> + if (ret)
>> + dev_err(dev, "WA for Errata i870 not appplied. Update DT\n");
>
> Hi Vignesh,
>
> Nit: s/appplied/applied
>

Oops, let me know if you want me to resend with this fixed.

> Two questions:
>
> - Current code applies the unaligned_memaccess() workaround for all
> compatible variants. This is fine for current controllers (since
> they are all affected), the code path above will have to be
> reworked if there is any other compatible IP re-using the driver
> that does not require the workaround.

There are no compatible IPs that don't require this workaround. Also, I
don't see this IP being re-used in future. If you insist, I can add a
errata flag

> - How do you want this series to go upstream ? If it goes via arm-soc,
> which I think it should, here is my ACK on this patch:
>
Patch 1 and 2(dt bindings update and driver patch) can go in via PCI
tree. And DT changes(patch 3 and 4) can be picked up by Tony via
omap/arm-soc tree. They are mostly independent and should not cause any
problems. Does that sound good?

> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
>

Thanks!

> Please let me know if I can drop this series from the PCI patchwork.
>
> Thanks,
> Lorenzo
>
>> +
>> switch (mode) {
>> case DW_PCIE_RC_TYPE:
>> if (!IS_ENABLED(CONFIG_PCI_DRA7XX_HOST)) {
>> @@ -717,10 +721,6 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
>> 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;
>> --
>> 2.18.0
>>

--
Regards
Vignesh