| Message ID | 20170321134203.26325-3-andrew.smirnov@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Am Dienstag, den 21.03.2017, 06:42 -0700 schrieb Andrey Smirnov: > Some designs implement reset GPIO via a GPIO expander connected to a > peripheral bus. One such example would be i.MX7 Sabre board where said > GPIO is provided by SPI shift register connected to a bitbanged SPI > bus. In order to support such designs allow reset GPIO request to defer > probing of the driver. > > Cc: yurovsky@gmail.com > Cc: Lucas Stach <l.stach@pengutronix.de> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Fabio Estevam <fabio.estevam@nxp.com> > Cc: Dong Aisheng <dongas86@gmail.com> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Reviewed-by: Lucas Stach <l.stach@pengutronix.de> > --- > drivers/pci/dwc/pci-imx6.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c > index e0c36d6..64de9bb 100644 > --- a/drivers/pci/dwc/pci-imx6.c > +++ b/drivers/pci/dwc/pci-imx6.c > @@ -595,8 +595,8 @@ static struct dw_pcie_host_ops imx6_pcie_host_ops = { > .host_init = imx6_pcie_host_init, > }; > > -static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie, > - struct platform_device *pdev) > +static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie, > + struct platform_device *pdev) > { > struct dw_pcie *pci = imx6_pcie->pci; > struct pcie_port *pp = &pci->pp; > @@ -636,7 +636,7 @@ static const struct dw_pcie_ops dw_pcie_ops = { > .link_up = imx6_pcie_link_up, > }; > > -static int __init imx6_pcie_probe(struct platform_device *pdev) > +static int imx6_pcie_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > struct dw_pcie *pci; > @@ -660,10 +660,6 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) > imx6_pcie->variant = > (enum imx6_pcie_variants)of_device_get_match_data(dev); > > - /* Added for PCI abort handling */ > - hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0, > - "imprecise external abort"); > - > dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0); > pci->dbi_base = devm_ioremap_resource(dev, dbi_base); > if (IS_ERR(pci->dbi_base)) > @@ -683,6 +679,8 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) > dev_err(dev, "unable to get reset gpio\n"); > return ret; > } > + } else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) { > + return imx6_pcie->reset_gpio; > } > > /* Fetch clocks */ > @@ -796,11 +794,22 @@ static struct platform_driver imx6_pcie_driver = { > .name = "imx6q-pcie", > .of_match_table = imx6_pcie_of_match, > }, > + .probe = imx6_pcie_probe, > .shutdown = imx6_pcie_shutdown, > }; > > static int __init imx6_pcie_init(void) > { > - return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe); > + /* > + * Since probe() can be deferred we need to make sure that > + * hook_fault_code is not called after __init memory is freed > + * by kernel and since imx6q_pcie_abort_handler() is a no-op > + * we can install the handler here without risking it > + * accessing some unitialized driver state > + */ > + hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0, > + "imprecise external abort"); > + > + return platform_driver_register(&imx6_pcie_driver); > } > device_initcall(imx6_pcie_init);
diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c index e0c36d6..64de9bb 100644 --- a/drivers/pci/dwc/pci-imx6.c +++ b/drivers/pci/dwc/pci-imx6.c @@ -595,8 +595,8 @@ static struct dw_pcie_host_ops imx6_pcie_host_ops = { .host_init = imx6_pcie_host_init, }; -static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie, - struct platform_device *pdev) +static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie, + struct platform_device *pdev) { struct dw_pcie *pci = imx6_pcie->pci; struct pcie_port *pp = &pci->pp; @@ -636,7 +636,7 @@ static const struct dw_pcie_ops dw_pcie_ops = { .link_up = imx6_pcie_link_up, }; -static int __init imx6_pcie_probe(struct platform_device *pdev) +static int imx6_pcie_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct dw_pcie *pci; @@ -660,10 +660,6 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) imx6_pcie->variant = (enum imx6_pcie_variants)of_device_get_match_data(dev); - /* Added for PCI abort handling */ - hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0, - "imprecise external abort"); - dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0); pci->dbi_base = devm_ioremap_resource(dev, dbi_base); if (IS_ERR(pci->dbi_base)) @@ -683,6 +679,8 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) dev_err(dev, "unable to get reset gpio\n"); return ret; } + } else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) { + return imx6_pcie->reset_gpio; } /* Fetch clocks */ @@ -796,11 +794,22 @@ static struct platform_driver imx6_pcie_driver = { .name = "imx6q-pcie", .of_match_table = imx6_pcie_of_match, }, + .probe = imx6_pcie_probe, .shutdown = imx6_pcie_shutdown, }; static int __init imx6_pcie_init(void) { - return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe); + /* + * Since probe() can be deferred we need to make sure that + * hook_fault_code is not called after __init memory is freed + * by kernel and since imx6q_pcie_abort_handler() is a no-op + * we can install the handler here without risking it + * accessing some unitialized driver state + */ + hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0, + "imprecise external abort"); + + return platform_driver_register(&imx6_pcie_driver); } device_initcall(imx6_pcie_init);
Some designs implement reset GPIO via a GPIO expander connected to a peripheral bus. One such example would be i.MX7 Sabre board where said GPIO is provided by SPI shift register connected to a bitbanged SPI bus. In order to support such designs allow reset GPIO request to defer probing of the driver. Cc: yurovsky@gmail.com Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Fabio Estevam <fabio.estevam@nxp.com> Cc: Dong Aisheng <dongas86@gmail.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> --- drivers/pci/dwc/pci-imx6.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)