Hi Kishon, > Hi, > > On Sunday 15 January 2017 06:49 PM, Lukasz Majewski wrote: > > Some devices (due to e.g. bad PCIe signal integrity) require to run > > with forced GEN1 speed on PCIe bus. > > > > This patch changes the speed explicitly on dra7 based devices when > > proper device tree attribute is defined for the PCIe controller. > > > > Signed-off-by: Lukasz Majewski <lukma@xxxxxxx> > > Bjorn has already queued a patch to do the same thing > https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/log/?h=pci/host-dra7xx It seems like Bjorn only modifies CAP registers. He also needs to change register with 0x080C offset to actually ( PCIECTRL_PL_WIDTH_SPEED_CTL ) Best regards, Łukasz > > Thanks > Kishon > > > --- > > > > Patch applies on newest origin/master > > SHA1: f4d3935e4f4884ba80561db5549394afb8eef8f7 > > > > Tested at AM5728 > > > > --- > > Documentation/devicetree/bindings/pci/ti-pci.txt | 1 + > > drivers/pci/host/pci-dra7xx.c | 23 > > +++++++++++++++++++++++ > > drivers/pci/host/pcie-designware.h | 1 + 3 files > > changed, 25 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt > > b/Documentation/devicetree/bindings/pci/ti-pci.txt index > > 60e2516..9f97409 100644 --- > > a/Documentation/devicetree/bindings/pci/ti-pci.txt +++ > > b/Documentation/devicetree/bindings/pci/ti-pci.txt @@ -25,6 +25,7 > > @@ PCIe Designware Controller > > Optional Property: > > - gpios : Should be added if a gpio line is required to drive > > PERST# line > > + - to,pcie-is-gen1: Indicates that forced gen1 port operation is > > needed. > > Example: > > axi { > > diff --git a/drivers/pci/host/pci-dra7xx.c > > b/drivers/pci/host/pci-dra7xx.c index 9595fad..eec5fae 100644 > > --- a/drivers/pci/host/pci-dra7xx.c > > +++ > > b/drivers/pci/host/pci-https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/log/?h=pci/host-dra7xxdra7xx.c > > @@ -63,6 +63,13 @@ #define > > LINK_UP BIT(16) > > #define > > DRA7XX_CPU_TO_BUS_ADDR 0x0FFFFFFF > > +#define PCIECTRL_EP_DBICS_LNK_CAP > > 0x007C +#define > > MAX_LINK_SPEEDS_MASK GENMASK(3, 0) > > +#define MAX_LINK_SPEEDS_GEN1 > > BIT(0) + +#define > > PCIECTRL_PL_WIDTH_SPEED_CTL 0x080C > > +#define CFG_DIRECTED_SPEED_CHANGE > > BIT(17) + struct dra7xx_pcie { struct pcie_port pp; > > void __iomem *base; /* DT > > ti_conf */ @@ -270,6 +277,7 @@ static int __init > > dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, struct pcie_port > > *pp = &dra7xx->pp; struct device *dev = pp->dev; > > struct resource *res; > > + u32 val; > > > > pp->irq = platform_get_irq(pdev, 1); > > if (pp->irq < 0) { > > @@ -296,6 +304,18 @@ static int __init dra7xx_add_pcie_port(struct > > dra7xx_pcie *dra7xx, if (!pp->dbi_base) > > return -ENOMEM; > > > > + if (pp->is_gen1) { > > + dev_info(dev, "GEN1 forced\n"); > > + > > + val = readl(pp->dbi_base + > > PCIECTRL_EP_DBICS_LNK_CAP); > > + set_mask_bits(&val, MAX_LINK_SPEEDS_MASK, > > MAX_LINK_SPEEDS_GEN1); > > + writel(val, pp->dbi_base + > > PCIECTRL_EP_DBICS_LNK_CAP); + > > + val = readl(pp->dbi_base + > > PCIECTRL_PL_WIDTH_SPEED_CTL); > > + val &= ~CFG_DIRECTED_SPEED_CHANGE; > > + writel(val, pp->dbi_base + > > PCIECTRL_PL_WIDTH_SPEED_CTL); > > + } > > + > > ret = dw_pcie_host_init(pp); > > if (ret) { > > dev_err(dev, "failed to initialize host\n"); > > @@ -404,6 +424,9 @@ static int __init dra7xx_pcie_probe(struct > > platform_device *pdev) goto err_gpio; > > } > > > > + if (of_property_read_bool(np, "ti,pcie-is-gen1")) > > + pp->is_gen1 = true; > > + > > reg = dra7xx_pcie_readl(dra7xx, > > PCIECTRL_DRA7XX_CONF_DEVICE_CMD); reg &= ~LTSSM_EN; > > dra7xx_pcie_writel(dra7xx, > > PCIECTRL_DRA7XX_CONF_DEVICE_CMD, reg); diff --git > > a/drivers/pci/host/pcie-designware.h > > b/drivers/pci/host/pcie-designware.h index a567ea2..2fb0b18 100644 > > --- a/drivers/pci/host/pcie-designware.h +++ > > b/drivers/pci/host/pcie-designware.h @@ -50,6 +50,7 @@ struct > > pcie_port { struct irq_domain *irq_domain; > > unsigned long msi_data; > > u8 iatu_unroll_enabled; > > + u8 is_gen1; > > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); > > }; > > > > Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@xxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
