On 3/7/19 9:50 PM, Bjorn Helgaas wrote:
> On Sun, Feb 17, 2019 at 02:24:41PM +0100, [email protected] wrote:
>> From: Kazufumi Ikeda <[email protected]>
>>
>> Reestablish the PCIe link very early in the resume process in case it
>> went down to prevent PCI accesses from hanging the bus. Such accesses
>> can happen early in the PCI resume process, in the resume_noirq, thus
>> the link must be reestablished in the resume_noirq callback of the
>> driver.
>>
>> Signed-off-by: Kazufumi Ikeda <[email protected]>
>> Signed-off-by: Gaku Inami <[email protected]>
>> Signed-off-by: Marek Vasut <[email protected]>
>> Cc: Geert Uytterhoeven <[email protected]>
>> Cc: Phil Edworthy <[email protected]>
>> Cc: Simon Horman <[email protected]>
>> Cc: Wolfram Sang <[email protected]>
>> Cc: [email protected]
>> ---
>> V2: - Use BIT() macro for (1 << n)
>> - Since polling in rcar_pcie_wait_for_dl() uses udelay(), do not
>> add extra changes to this function anymore
>> - Make resume_noirq return early and clean up parenthesis therein
>> ---
>> drivers/pci/controller/pcie-rcar.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pcie-rcar.c
>> b/drivers/pci/controller/pcie-rcar.c
>> index c8febb009454..b8f8fb3bc640 100644
>> --- a/drivers/pci/controller/pcie-rcar.c
>> +++ b/drivers/pci/controller/pcie-rcar.c
>> @@ -46,6 +46,7 @@
>>
>> /* Transfer control */
>> #define PCIETCTLR 0x02000
>> +#define DL_DOWN BIT(3)
>> #define CFINIT 1
>
> I saw discussion after the V1 patch about using BIT() and making
> similar constants also use BIT() for consistency. That makes sense to
> me, and I think the best way would be:
>
> 1) in *this* patch, use "#define DL_DOWN 8"
> 2) in a followup patch, convert them all to BIT()
>
> That way each revision of pcie-rcar.c is self-consistent.
But the BIT() macros are already cleaned , see commit
0ee40820989b330e24926d82953ffb9e1c7a8425
PCI: rcar: Clean up the macros
>> #define PCIETSTR 0x02004
>> #define DATA_LINK_ACTIVE 1
>> @@ -1130,6 +1131,7 @@ static int rcar_pcie_probe(struct platform_device
>> *pdev)
>> pcie = pci_host_bridge_priv(bridge);
>>
>> pcie->dev = dev;
>> + platform_set_drvdata(pdev, pcie);
>>
>> err = pci_parse_request_of_pci_ranges(dev, &pcie->resources, NULL);
>> if (err)
>> @@ -1221,10 +1223,28 @@ static int rcar_pcie_probe(struct platform_device
>> *pdev)
>> return err;
>> }
>>
>> +static int rcar_pcie_resume_noirq(struct device *dev)
>> +{
>> + struct rcar_pcie *pcie = dev_get_drvdata(dev);
>> +
>> + if (rcar_pci_read_reg(pcie, PMSR) &&
>> + !(rcar_pci_read_reg(pcie, PCIETCTLR) & DL_DOWN))
>> + return 0;
>> +
>> + /* Re-establish the PCIe link */
>> + rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
>> + return rcar_pcie_wait_for_dl(pcie);
>> +}
>> +
>> +static const struct dev_pm_ops rcar_pcie_pm_ops = {
>> + .resume_noirq = rcar_pcie_resume_noirq,
>> +};
>
> I think there's the beginning of a convention to use #ifdef
> CONFIG_PM_SLEEP around the ops themselves [1]. Otherwise I think
> we'll get a warning about unused code when CONFIG_PM_SLEEP is unset.
Only if I used SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() , but I set the
resume_noirq directly.
>> static struct platform_driver rcar_pcie_driver = {
>> .driver = {
>> .name = "rcar-pcie",
>> .of_match_table = rcar_pcie_of_match,
>> + .pm = &rcar_pcie_pm_ops,
>> .suppress_bind_attrs = true,
>> },
>> .probe = rcar_pcie_probe,
>> --
>> 2.19.2
>>
>
> [1]
> https://lore.kernel.org/linux-pci/[email protected]
>
--
Best regards,
Marek Vasut
