Bjorn, thanks for the comments!
On 12/16/2015 11:53 PM, Bjorn Helgaas wrote:
> On Thu, Dec 03, 2015 at 03:35:22PM +0200, Stanimir Varbanov wrote:
>> From: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
>>
>> The PCIe driver reuse the Designware common code for host
>> and MSI initialization, and also program the Qualcomm
>> application specific registers.
>>
>> Signed-off-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
>> ---
>> MAINTAINERS | 7 +
>> drivers/pci/host/Kconfig | 10 +
>> drivers/pci/host/Makefile | 1 +
>> drivers/pci/host/pcie-qcom.c | 624 ++++++++++++++++++++++++++++++++++++++++++
>
>> +#define PCIE20_CAP 0x70
>> +#define PCIE20_CAP_LINKCTRLSTATUS (PCIE20_CAP + 0x10)
>> +#define PCIE20_CAP_LINKCTRLSTATUS_LINK_UP BIT(29)
>
> This looks like it could be referring to a standard PCIe Capability;
> could you use the existing PCI_EXP_LNKSTA and PCI_EXP_LNKSTA_DLLLA
> symbols here? And readw() instead of readl()?
Yes, that is possible but I still need to keep PCIE20_CAP capabilities
offset.
>
>> +static int qcom_pcie_enable_link_training(struct qcom_pcie *pcie)
>> +{
>> + struct device *dev = pcie->dev;
>> + u32 val;
>> + int ret;
>> +
>> + /* enable link training */
>> + val = readl(pcie->elbi + PCIE20_ELBI_SYS_CTRL);
>> + val |= PCIE20_ELBI_SYS_CTRL_LT_ENABLE;
>> + writel(val, pcie->elbi + PCIE20_ELBI_SYS_CTRL);
>> +
>> + /* wait for up to 100ms for the link to come up */
>> + ret = readl_poll_timeout(pcie->elbi + PCIE20_ELBI_SYS_STTS, val,
>> + val & XMLH_LINK_UP, LINKUP_DELAY_US,
>> + LINKUP_TIMEOUT_US);
>> +
>> + if (ret < 0 || !dw_pcie_link_up(&pcie->pp)) {
>> + dev_err(dev, "link initialization failed\n");
>> + return -ETIMEDOUT;
>> + }
>> +
>> + return 0;
>> +}
>
> This looks a lot like the *_establish_link() functions in other
> DesignWare-based drivers. Can you make it look even more similar,
> e.g., by renaming it to qcom_pcie_establish_link() and maybe moving
> some of the PHY functionality here?
>
> readl_poll_timeout() is nice and avoids the hand-coded timeout loop
> the other drivers use. But is there benefit in checking for
> XMLH_LINK_UP, or could you simply poll dw_pcie_link_up() like the
> others do? If it's sufficient, I'd prefer using dw_pcie_link_up()
> by itself because it's a little more generic.
OK I will modify the code to use dw_pcie_link_up() and ensure that this
check is sufficient.
--
regards,
Stan
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