Re: [PATCH v9 05/16] PCI: imx6: Using "linux,pci-domain" as slot ID

Lorenzo Pieralisi
2024-02-02T12:12:49Z

"PCI: imx6: Use "linux,pci-domain" as slot ID"

On Fri, Jan 19, 2024 at 12:11:11PM -0500, Frank Li wrote:
> Avoid use get slot id by compared with register physical address. If there
> are more than 2 slots, compared logic will become complex.
>
> "linux,pci-domain" already exist at dts since commit:
> commit (c0b70f05c87f3b arm64: dts: imx8mq: use_dt_domains for pci node).
>
> So it is safe to remove compare basic address code:
> ...
> if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> imx6_pcie->controller_id = 1;

No it is not unless you magically update all firmware out
there in the field.

> ...
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>
> Notes:
> Change from v7 to v8
> - fixed comments
> - Added Manivannan Sadhasivam's review tag
> Change from v5 to v7
> - none
> Change from v3 to v4
> - remove compare basic address logic
> Change from v2 to v3
> - none
> Change from v1 to v2
> - fix of_get_pci_domain_nr return value check logic
>
> drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index eda6bc6ef80ee..773411d20329f 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -33,6 +33,7 @@
> #include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
>
> +#include "../../pci.h"
> #include "pcie-designware.h"
>
> #define IMX8MQ_GPR_PCIE_REF_USE_PAD BIT(9)
> @@ -40,7 +41,6 @@
> #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE BIT(11)
> #define IMX8MQ_GPR_PCIE_VREG_BYPASS BIT(12)
> #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE GENMASK(11, 8)
> -#define IMX8MQ_PCIE2_BASE_ADDR 0x33c00000
>
> #define to_imx6_pcie(x) dev_get_drvdata((x)->dev)
>
> @@ -1279,13 +1279,17 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> "Failed to get PCIEPHY reset control\n");
> }
>
> - switch (imx6_pcie->drvdata->variant) {
> - case IMX7D:
> - if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> - imx6_pcie->controller_id = 1;
> - default:
> - break;
> - }
> + /* Using linux,pci-domain as PCI slot id */
> + imx6_pcie->controller_id = of_get_pci_domain_nr(node);
> + /*
> + * If there are no "linux,pci-domain" property specified in DT, then assume only one
> + * controller is available.
> + */
> + if (imx6_pcie->controller_id == -EINVAL)
> + imx6_pcie->controller_id = 0;

See above, this breaks compatibility with old DTs (and -EINVAL is not
the only error code you should handle).

Lorenzo

> + else if (imx6_pcie->controller_id < 0)
> + return dev_err_probe(dev, imx6_pcie->controller_id,
> + "linux,pci-domain have wrong value\n");
>
> /* Grab turnoff reset */
> imx6_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
> --
> 2.34.1
>