| Message ID | 1378958611-4274-4-git-send-email-xobs@kosagi.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Sean, Several more comments. Shawn, A question about a clk_set_parent inside. On Thu, Sep 12, 2013 at 04:03:31AM +0000, Sean Cross wrote: > + > +#define IMX6_ENTER_RESET 0 > +#define IMX6_EXIT_RESET 1 These are unused > + > +#define IMX6_POWER_OFF 0 > +#define IMX6_POWER_ON 1 unused aswell > +static int pcie_phy_poll_ack(void __iomem *dbi_base, int max_iterations, > + int exp_val) > +{ > + u32 val; > + u32 wait_counter = 0; > + > + do { > + val = readl(dbi_base + PCIE_PHY_STAT); > + val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; > + wait_counter++; > + } while ((wait_counter < max_iterations) && (val != exp_val)); may_iterations is never something else than 100 so you should drop the argument. Also I would prefer a real timeout here rather than a counter. > + > + if (val != exp_val) > + return -1; By saying "A negative error value" I actually meant one of include/uapi/asm-generic/errno* > +static int pcie_phy_write(void __iomem *dbi_base, int addr, int data) > +{ > + u32 var; > + > + /* write addr */ > + /* cap addr */ > + if (pcie_phy_wait_ack(dbi_base, addr)) > + return -1; > + > + var = data << PCIE_PHY_CTRL_DATA_LOC; > + writel(var, dbi_base + PCIE_PHY_CTRL); > + > + /* capture data */ > + var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC); > + writel(var, dbi_base + PCIE_PHY_CTRL); > + > + /* wait for ack */ Drop this comment. > + if (pcie_phy_poll_ack(dbi_base, 100, 1)) > + return -1; > + ... > +static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > +{ > + int ret; > + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); > + > + if (imx6_pcie->power_on_gpio >= 0) > + gpio_set_value(imx6_pcie->power_on_gpio, IMX6_POWER_ON); in probe you used gpio_is_valid(). Why not here? > + > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > + > + ret = clk_set_parent(imx6_pcie->lvds1_sel, imx6_pcie->sata_ref); > + if (ret) { > + dev_err(pp->dev, "unable to set lvds1_gate parent\n"); > + goto err_set_parent; > + } I'm unsure this should be done here. Shawn, should we do this in SoC code? > + > + ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m); > + if (ret) { > + dev_err(pp->dev, "unable to enable pcie_ref_125m\n"); > + goto err_pcie_ref; > + } > + > + ret = clk_prepare_enable(imx6_pcie->lvds1_gate); > + if (ret) { > + dev_err(pp->dev, "unable to enable lvds1_gate\n"); > + goto err_lvds1_gate; > + } > + > + ret = clk_prepare_enable(imx6_pcie->pcie_axi); > + if (ret) { > + dev_err(pp->dev, "unable to enable pcie_axi\n"); > + goto err_pcie_axi; > + } > + > + /* allow the clocks to stabilize */ > + usleep_range(100, 200); > + > + return 0; > + > +err_pcie_axi: > + clk_disable(imx6_pcie->lvds1_gate); The counterpart of clk_prepare_enable is clk_disable_unprepare. > + return; > + } > + } > + > + return; unnecessary return > + > + imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0); > + if (gpio_is_valid(imx6_pcie->power_on_gpio)) > + devm_gpio_request_one(&pdev->dev, imx6_pcie->power_on_gpio, > + GPIOF_OUT_INIT_LOW, > + "PCIe power enable"); devm_gpio_request_one can still fail. > + > + imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0); > + if (gpio_is_valid(imx6_pcie->wake_up_gpio)) > + devm_gpio_request_one(&pdev->dev, imx6_pcie->wake_up_gpio, > + GPIOF_IN, > + "PCIe wake up"); > + > + imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0); > + if (gpio_is_valid(imx6_pcie->disable_gpio)) > + devm_gpio_request_one(&pdev->dev, imx6_pcie->disable_gpio, > + GPIOF_OUT_INIT_HIGH, > + "PCIe disable endpoint"); > + > + /* Fetch clocks */ > + imx6_pcie->lvds1_sel = clk_get(&pdev->dev, "lvds1_sel"); > + if (IS_ERR(imx6_pcie->lvds1_sel)) { > + dev_err(&pdev->dev, > + "lvds1_sel clock missing or invalid\n"); > + ret = PTR_ERR(imx6_pcie->lvds1_sel); > + goto err; > + } > + > + imx6_pcie->lvds1_gate = clk_get(&pdev->dev, "lvds1_gate"); > + if (IS_ERR(imx6_pcie->lvds1_gate)) { > + dev_err(&pdev->dev, > + "lvds1_gate clock select missing or invalid\n"); > + ret = PTR_ERR(imx6_pcie->lvds1_gate); > + goto err; > + } devm_clk_get(). Otherwise you need to release the clock un unregister/probe failure. > +static int __exit imx6_pcie_remove(struct platform_device *pdev) > +{ > + struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); > + > + clk_disable_unprepare(imx6_pcie->pcie_axi); > + clk_disable_unprepare(imx6_pcie->lvds1_gate); > + clk_disable_unprepare(imx6_pcie->pcie_ref_125m); Still no unregister for the pcie controller? > + > + return 0; > +} > + Sascha
> Sean, > > Several more comments. > > Shawn, > > A question about a clk_set_parent inside. > > On Thu, Sep 12, 2013 at 04:03:31AM +0000, Sean Cross wrote: > > + > > +#define IMX6_ENTER_RESET 0 > > +#define IMX6_EXIT_RESET 1 > > > > These are unused > > > + > > +#define IMX6_POWER_OFF 0 > > +#define IMX6_POWER_ON 1 > > > > unused aswell > Thanks. These leaked out from an earlier revision of the code. I'll remove them. > > > +static int pcie_phy_poll_ack(void __iomem *dbi_base, int max_iterations, > > + int exp_val) > > +{ > > + u32 val; > > + u32 wait_counter = 0; > > + > > + do { > > + val = readl(dbi_base + PCIE_PHY_STAT); > > + val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; > > + wait_counter++; > > + } while ((wait_counter < max_iterations) && (val != exp_val)); > > > > may_iterations is never something else than 100 so you should drop the > argument. > Also I would prefer a real timeout here rather than a counter. Is there a construct to have a real timer? Would a completion work here instead? > > + > > + if (val != exp_val) > > + return -1; > > > > By saying "A negative error value" I actually meant one of > include/uapi/asm-generic/errno* Of course. How silly of me. I'll fix that correctly. > > +static int pcie_phy_write(void __iomem *dbi_base, int addr, int data) > > +{ > > + u32 var; > > + > > + /* write addr */ > > + /* cap addr */ > > + if (pcie_phy_wait_ack(dbi_base, addr)) > > + return -1; > > + > > + var = data << PCIE_PHY_CTRL_DATA_LOC; > > + writel(var, dbi_base + PCIE_PHY_CTRL); > > + > > + /* capture data */ > > + var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC); > > + writel(var, dbi_base + PCIE_PHY_CTRL); > > + > > + /* wait for ack */ > > > > Drop this comment. > > > + if (pcie_phy_poll_ack(dbi_base, 100, 1)) > > + return -1; > > + > > > > ... > > > +static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > > +{ > > + int ret; > > + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); > > + > > + if (imx6_pcie->power_on_gpio >= 0) > > + gpio_set_value(imx6_pcie->power_on_gpio, IMX6_POWER_ON); > > > > in probe you used gpio_is_valid(). Why not here? Again, leftover from when that used to be exynos_pcie_assert_reset(). I'll change it to use gpio_is_valid(). > > + > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > > + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > > + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > > + > > + ret = clk_set_parent(imx6_pcie->lvds1_sel, imx6_pcie->sata_ref); > > + if (ret) { > > + dev_err(pp->dev, "unable to set lvds1_gate parent\n"); > > + goto err_set_parent; > > + } > > > > I'm unsure this should be done here. Shawn, should we do this in SoC > code? A different board could easily use lvds2 to drive the PCIe clock. I think that I should change the variable names to simply "lvds_sel". > > + > > + ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m); > > + if (ret) { > > + dev_err(pp->dev, "unable to enable pcie_ref_125m\n"); > > + goto err_pcie_ref; > > + } > > + > > + ret = clk_prepare_enable(imx6_pcie->lvds1_gate); > > + if (ret) { > > + dev_err(pp->dev, "unable to enable lvds1_gate\n"); > > + goto err_lvds1_gate; > > + } > > + > > + ret = clk_prepare_enable(imx6_pcie->pcie_axi); > > + if (ret) { > > + dev_err(pp->dev, "unable to enable pcie_axi\n"); > > + goto err_pcie_axi; > > + } > > + > > + /* allow the clocks to stabilize */ > > + usleep_range(100, 200); > > + > > + return 0; > > + > > +err_pcie_axi: > > + clk_disable(imx6_pcie->lvds1_gate); > > > > The counterpart of clk_prepare_enable is clk_disable_unprepare. I'll fix this, too. > > + return; > > + } > > + } > > + > > + return; > > > > unnecessary return I'll turn it into a "break" then. > > + > > + imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0); > > + if (gpio_is_valid(imx6_pcie->power_on_gpio)) > > + devm_gpio_request_one(&pdev->dev, imx6_pcie->power_on_gpio, > > + GPIOF_OUT_INIT_LOW, > > + "PCIe power enable"); > > > > devm_gpio_request_one can still fail. It can fail, but it's only critical for the power switch. However, arguably it's a critical error even if these GPIOs can't be allocated, so I'll go ahead and add the same consistency check and error return code to the other three switches. > > + > > + imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0); > > + if (gpio_is_valid(imx6_pcie->wake_up_gpio)) > > + devm_gpio_request_one(&pdev->dev, imx6_pcie->wake_up_gpio, > > + GPIOF_IN, > > + "PCIe wake up"); > > + > > + imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0); > > + if (gpio_is_valid(imx6_pcie->disable_gpio)) > > + devm_gpio_request_one(&pdev->dev, imx6_pcie->disable_gpio, > > + GPIOF_OUT_INIT_HIGH, > > + "PCIe disable endpoint"); > > + > > + /* Fetch clocks */ > > + imx6_pcie->lvds1_sel = clk_get(&pdev->dev, "lvds1_sel"); > > + if (IS_ERR(imx6_pcie->lvds1_sel)) { > > + dev_err(&pdev->dev, > > + "lvds1_sel clock missing or invalid\n"); > > + ret = PTR_ERR(imx6_pcie->lvds1_sel); > > + goto err; > > + } > > + > > + imx6_pcie->lvds1_gate = clk_get(&pdev->dev, "lvds1_gate"); > > + if (IS_ERR(imx6_pcie->lvds1_gate)) { > > + dev_err(&pdev->dev, > > + "lvds1_gate clock select missing or invalid\n"); > > + ret = PTR_ERR(imx6_pcie->lvds1_gate); > > + goto err; > > + } > > > > devm_clk_get(). Otherwise you need to release the clock un > unregister/probe failure. Good point. > > +static int __exit imx6_pcie_remove(struct platform_device *pdev) > > +{ > > + struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); > > + > > + clk_disable_unprepare(imx6_pcie->pcie_axi); > > + clk_disable_unprepare(imx6_pcie->lvds1_gate); > > + clk_disable_unprepare(imx6_pcie->pcie_ref_125m); > > > > Still no unregister for the pcie controller? The Designware core doesn't support unregistering (or even module unloading). I'm not sure how to handle that case. For that matter, when is remove() even called on a module that can't be unloaded? -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Sep 12, 2013 at 02:44:01PM +0800, Sean Cross wrote: > > Sean, > > > > Several more comments. > > > > Shawn, > > > > A question about a clk_set_parent inside. > > > > On Thu, Sep 12, 2013 at 04:03:31AM +0000, Sean Cross wrote: > > > + > > > +#define IMX6_ENTER_RESET 0 > > > +#define IMX6_EXIT_RESET 1 > > > > > > > > These are unused > > > > > + > > > +#define IMX6_POWER_OFF 0 > > > +#define IMX6_POWER_ON 1 > > > > > > > > unused aswell > > > Thanks. These leaked out from an earlier revision of the code. I'll remove them. > > > > > +static int pcie_phy_poll_ack(void __iomem *dbi_base, int max_iterations, > > > + int exp_val) > > > +{ > > > + u32 val; > > > + u32 wait_counter = 0; > > > + > > > + do { > > > + val = readl(dbi_base + PCIE_PHY_STAT); > > > + val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; > > > + wait_counter++; > > > + } while ((wait_counter < max_iterations) && (val != exp_val)); > > > > > > > > may_iterations is never something else than 100 so you should drop the > > argument. > > Also I would prefer a real timeout here rather than a counter. > > Is there a construct to have a real timer? Would a completion work here instead? A completion is overkill. Polling is fine, but it should be a well defined amount of time which is independent of current cpu speed. Adding a udelay(1) to the loop should be enough. > > > > > > I'm unsure this should be done here. Shawn, should we do this in SoC > > code? > > A different board could easily use lvds2 to drive the PCIe clock. I think that I should change the variable names to simply "lvds_sel". Why should it use a different clock? It's fine to make this configurable, but only if we actually know the reasons why it should be configurable. Even if it should be configurable I'm still unsure whether this should be done at pci driver level. > > > > > > devm_gpio_request_one can still fail. > It can fail, but it's only critical for the power switch. However, arguably it's a critical error even if these GPIOs can't be allocated, so I'll go ahead and add the same consistency check and error return code to the other three switches. If you want to make the gpios optional that's fine, but when of_get_named_gpio succeeds, then devm_gpio_request_one should succeed aswell, otherwise there's something wrong. > > > + struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); > > > + > > > + clk_disable_unprepare(imx6_pcie->pcie_axi); > > > + clk_disable_unprepare(imx6_pcie->lvds1_gate); > > > + clk_disable_unprepare(imx6_pcie->pcie_ref_125m); > > > > > > > > Still no unregister for the pcie controller? > The Designware core doesn't support unregistering (or even module unloading). I'm not sure how to handle that case. For that matter, when is remove() even called on a module that can't be unloaded? Then don't implement the remove callback. That's better than providing a bogus remove function. Sascha
On Thursday, 12 September, 2013 at 3:01 PM, Sascha Hauer wrote: > On Thu, Sep 12, 2013 at 02:44:01PM +0800, Sean Cross wrote: > > > Sean, > > > > > > Several more comments. > > > > > > > +static int pcie_phy_poll_ack(void __iomem *dbi_base, int max_iterations, > > > > + int exp_val) > > > > +{ > > > > + u32 val; > > > > + u32 wait_counter = 0; > > > > + > > > > + do { > > > > + val = readl(dbi_base + PCIE_PHY_STAT); > > > > + val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; > > > > + wait_counter++; > > > > + } while ((wait_counter < max_iterations) && (val != exp_val)); > > > > > > > > > > > > > > > > > > may_iterations is never something else than 100 so you should drop the > > > argument. > > > Also I would prefer a real timeout here rather than a counter. > > > > > > > > Is there a construct to have a real timer? Would a completion work here instead? > > A completion is overkill. Polling is fine, but it should be a well > defined amount of time which is independent of current cpu speed. Adding > a udelay(1) to the loop should be enough. In that case, it makes sense to drop the max_iterations value by a factor of 10 or so. > > > > > > > > > I'm unsure this should be done here. Shawn, should we do this in SoC > > > code? > > > > > > > > A different board could easily use lvds2 to drive the PCIe clock. I think that I should change the variable names to simply "lvds_sel". > > Why should it use a different clock? It's fine to make this > configurable, but only if we actually know the reasons why it should be > configurable. > > Even if it should be configurable I'm still unsure whether this should > be done at pci driver level. I'm a bit wary of including clock setup like this in the SoC code, as different boards might be different. If a board designer wants to run LVDS2 to the PCIe slot, that's entirely acceptable. It might not actually ever get done, but it seems like the sort of board-specific thing that device tree was designed to handle. > > > devm_gpio_request_one can still fail. > > > > It can fail, but it's only critical for the power switch. However, arguably it's a critical error even if these GPIOs can't be allocated, so I'll go ahead and add the same consistency check and error return code to the other three switches. > > > > If you want to make the gpios optional that's fine, but when > of_get_named_gpio succeeds, then devm_gpio_request_one should succeed > aswell, otherwise there's something wrong. Ah, alright. I'll add the errors, then. > > > > + struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); > > > > + > > > > + clk_disable_unprepare(imx6_pcie->pcie_axi); > > > > + clk_disable_unprepare(imx6_pcie->lvds1_gate); > > > > + clk_disable_unprepare(imx6_pcie->pcie_ref_125m); > > > > > > > > > > > > > > > > > > Still no unregister for the pcie controller? > > The Designware core doesn't support unregistering (or even module unloading). I'm not sure how to handle that case. For that matter, when is remove() even called on a module that can't be unloaded? > > > > Then don't implement the remove callback. That's better than providing a > bogus remove function. I'll cut out the remove() function. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Sep 12, 2013 at 03:11:45PM +0800, Sean Cross wrote: > > Even if it should be configurable I'm still unsure whether this should > > be done at pci driver level. > > I'm a bit wary of including clock setup like this in the SoC code, as > different boards might be different. If a board designer wants to run > LVDS2 to the PCIe slot, that's entirely acceptable. It might not > actually ever get done, but it seems like the sort of board-specific > thing that device tree was designed to handle. The devicetree was designed to handle hardware descriptions, not configuration options. Chosing the clock parent is probably in the grey area between hardware description and configuration, so I assume when we find a good reason to add this option to the devicetree then it's acceptable to add it there. But we shouldn't add this option for something that, as you say, 'might not actually ever get done'. Just hardcode the clock selection in SoC code for now. If someone ever finds the good reason to make this configurable then he will speak up and we can discuss this again. Sascha
diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt index eabcb4b..41d8419 100644 --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt @@ -21,6 +21,11 @@ Required properties: - num-lanes: number of lanes to use - reset-gpio: gpio pin number of power good signal +Optional properties for fsl,imx6-pcie +- power-on-gpio: gpio pin number of power-enable signal +- wake-up-gpio: gpio pin number of incoming wakeup signal +- disable-gpio: gpio pin number of outgoing rfkill/endpoint disable signal + Example: SoC specific DT Entry: diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi index ccd55c2..ae51f60 100644 --- a/arch/arm/boot/dts/imx6qdl.dtsi +++ b/arch/arm/boot/dts/imx6qdl.dtsi @@ -116,6 +116,24 @@ arm,data-latency = <4 2 3>; }; + pcie: pcie@0x01000000 { + compatible = "fsl,imx6-pcie", "snps,dw-pcie"; + reg = <0x01ffc000 0x4000>; /* DBI */ + + #address-cells = <3>; + #size-cells = <2>; + device_type = "pci"; + ranges = <0x00000800 0 0x01f00000 0x01f00000 0 0x000fc000 /* configuration space */ + 0x81000000 0 0 0x01000000 0 0x00100000 /* downstream I/O */ + 0x82000000 0 0x01100000 0x01100000 0 0x00e00000>; /* non-prefetchable memory */ + + num-lanes = <1>; + interrupts = <0 123 0x04>; + clocks = <&clks 186>, <&clks 189>, <&clks 203>, <&clks 205>, <&clks 144>; + clock-names = "sata_ref", "pcie_ref_125m", "lvds1_sel", "lvds1_gate", "pcie_axi"; + status = "disabled"; + }; + pmu { compatible = "arm,cortex-a9-pmu"; interrupts = <0 94 0x04>; diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig index 29a8af6..e6ac281 100644 --- a/arch/arm/mach-imx/Kconfig +++ b/arch/arm/mach-imx/Kconfig @@ -801,6 +801,8 @@ config SOC_IMX6Q select HAVE_IMX_SRC select HAVE_SMP select MFD_SYSCON + select MIGHT_HAVE_PCI + select PCI_DOMAINS if PCI select PINCTRL select PINCTRL_IMX6Q select PL310_ERRATA_588369 if CACHE_PL310 diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig index 3d95048..efa24d9 100644 --- a/drivers/pci/host/Kconfig +++ b/drivers/pci/host/Kconfig @@ -15,6 +15,12 @@ config PCI_EXYNOS select PCIEPORTBUS select PCIE_DW +config PCI_IMX6 + bool "Freescale i.MX6 PCIe controller" + depends on SOC_IMX6Q + select PCIEPORTBUS + select PCIE_DW + config PCI_TEGRA bool "NVIDIA Tegra PCIe controller" depends on ARCH_TEGRA diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile index c9a997b..287d6a0 100644 --- a/drivers/pci/host/Makefile +++ b/drivers/pci/host/Makefile @@ -1,4 +1,5 @@ obj-$(CONFIG_PCIE_DW) += pcie-designware.o obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o +obj-$(CONFIG_PCI_IMX6) += pci-imx6.o obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c new file mode 100644 index 0000000..160bac2 --- /dev/null +++ b/drivers/pci/host/pci-imx6.c @@ -0,0 +1,549 @@ +/* + * PCIe host controller driver for Freescale i.MX6 SoCs + * + * Copyright (C) 2013 Kosagi + * http://www.kosagi.com + * + * Author: Sean Cross <xobs@kosagi.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/gpio.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_gpio.h> +#include <linux/pci.h> +#include <linux/platform_device.h> +#include <linux/resource.h> +#include <linux/signal.h> +#include <linux/types.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h> + +#include "pcie-designware.h" + +#define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp) + +struct imx6_pcie { + int reset_gpio; + int power_on_gpio; + int wake_up_gpio; + int disable_gpio; + struct clk *lvds1_sel; + struct clk *lvds1_gate; + struct clk *pcie_ref_125m; + struct clk *pcie_axi; + struct clk *sata_ref; + struct pcie_port pp; + struct regmap *iomuxc_gpr; + void __iomem *mem_base; +}; + +#define IMX6_ENTER_RESET 0 +#define IMX6_EXIT_RESET 1 + +#define IMX6_POWER_OFF 0 +#define IMX6_POWER_ON 1 + +/* PCIe Port Logic registers (memory-mapped) */ +#define PL_OFFSET 0x700 +#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28) +#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c) + +#define PCIE_PHY_CTRL (PL_OFFSET + 0x114) +#define PCIE_PHY_CTRL_DATA_LOC 0 +#define PCIE_PHY_CTRL_CAP_ADR_LOC 16 +#define PCIE_PHY_CTRL_CAP_DAT_LOC 17 +#define PCIE_PHY_CTRL_WR_LOC 18 +#define PCIE_PHY_CTRL_RD_LOC 19 + +#define PCIE_PHY_STAT (PL_OFFSET + 0x110) +#define PCIE_PHY_STAT_DATA_LOC 0 +#define PCIE_PHY_STAT_ACK_LOC 16 + +/* PHY registers (not memory-mapped) */ +#define PCIE_PHY_RX_ASIC_OUT 0x100D + +#define PHY_RX_OVRD_IN_LO 0x1005 +#define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1<<5) +#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1<<3) + +static int pcie_phy_poll_ack(void __iomem *dbi_base, int max_iterations, + int exp_val) +{ + u32 val; + u32 wait_counter = 0; + + do { + val = readl(dbi_base + PCIE_PHY_STAT); + val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1; + wait_counter++; + } while ((wait_counter < max_iterations) && (val != exp_val)); + + if (val != exp_val) + return -1; + + return 0; +} + +static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr) +{ + u32 val; + + val = addr << PCIE_PHY_CTRL_DATA_LOC; + writel(val, dbi_base + PCIE_PHY_CTRL); + + val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC); + writel(val, dbi_base + PCIE_PHY_CTRL); + + if (pcie_phy_poll_ack(dbi_base, 100, 1)) + return -1; + + val = addr << PCIE_PHY_CTRL_DATA_LOC; + writel(val, dbi_base + PCIE_PHY_CTRL); + + if (pcie_phy_poll_ack(dbi_base, 100, 0)) + return -1; + + return 0; +} + +/* Read from the 16-bt PCIe PHY control registers (not memory-mapped) */ +static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data) +{ + u32 val, phy_ctl; + + if (pcie_phy_wait_ack(dbi_base, addr)) + return -1; + + /* assert Read signal */ + phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC; + writel(phy_ctl, dbi_base + PCIE_PHY_CTRL); + + if (pcie_phy_poll_ack(dbi_base, 100, 1)) + return -1; + + val = readl(dbi_base + PCIE_PHY_STAT); + *data = (val & (0xffff << PCIE_PHY_STAT_DATA_LOC)); + + /* deassert Read signal */ + writel(0x00, dbi_base + PCIE_PHY_CTRL); + + if (pcie_phy_poll_ack(dbi_base, 100, 0)) + return -1; + + return 0; +} + +static int pcie_phy_write(void __iomem *dbi_base, int addr, int data) +{ + u32 var; + + /* write addr */ + /* cap addr */ + if (pcie_phy_wait_ack(dbi_base, addr)) + return -1; + + var = data << PCIE_PHY_CTRL_DATA_LOC; + writel(var, dbi_base + PCIE_PHY_CTRL); + + /* capture data */ + var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC); + writel(var, dbi_base + PCIE_PHY_CTRL); + + /* wait for ack */ + if (pcie_phy_poll_ack(dbi_base, 100, 1)) + return -1; + + /* deassert cap data */ + var = data << PCIE_PHY_CTRL_DATA_LOC; + writel(var, dbi_base + PCIE_PHY_CTRL); + + /* wait for ack de-assetion */ + if (pcie_phy_poll_ack(dbi_base, 100, 0)) + return -1; + + /* assert wr signal */ + var = 0x1 << PCIE_PHY_CTRL_WR_LOC; + writel(var, dbi_base + PCIE_PHY_CTRL); + + /* wait for ack */ + if (pcie_phy_poll_ack(dbi_base, 100, 1)) + return -1; + + /* deassert wr signal */ + var = data << PCIE_PHY_CTRL_DATA_LOC; + writel(var, dbi_base + PCIE_PHY_CTRL); + + /* wait for ack de-assetion */ + if (pcie_phy_poll_ack(dbi_base, 100, 0)) + return -1; + + writel(0x0, dbi_base + PCIE_PHY_CTRL); + + return 0; +} + +static int imx6_pcie_assert_core_reset(struct pcie_port *pp) +{ + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16); + + gpio_set_value(imx6_pcie->reset_gpio, 0); + msleep(100); + gpio_set_value(imx6_pcie->reset_gpio, 1); + + return 0; +} + +static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) +{ + int ret; + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + + if (imx6_pcie->power_on_gpio >= 0) + gpio_set_value(imx6_pcie->power_on_gpio, IMX6_POWER_ON); + + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); + + ret = clk_set_parent(imx6_pcie->lvds1_sel, imx6_pcie->sata_ref); + if (ret) { + dev_err(pp->dev, "unable to set lvds1_gate parent\n"); + goto err_set_parent; + } + + ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m); + if (ret) { + dev_err(pp->dev, "unable to enable pcie_ref_125m\n"); + goto err_pcie_ref; + } + + ret = clk_prepare_enable(imx6_pcie->lvds1_gate); + if (ret) { + dev_err(pp->dev, "unable to enable lvds1_gate\n"); + goto err_lvds1_gate; + } + + ret = clk_prepare_enable(imx6_pcie->pcie_axi); + if (ret) { + dev_err(pp->dev, "unable to enable pcie_axi\n"); + goto err_pcie_axi; + } + + /* allow the clocks to stabilize */ + usleep_range(100, 200); + + return 0; + +err_pcie_axi: + clk_disable(imx6_pcie->lvds1_gate); +err_lvds1_gate: + clk_disable(imx6_pcie->pcie_ref_125m); +err_pcie_ref: +err_set_parent: + return ret; +} + +static void imx6_pcie_init_phy(struct pcie_port *pp) +{ + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + + /* FIXME the field name should be aligned to RM */ + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_PCIE_CTL_2, 0 << 10); + + /* configure constant input signal to the pcie ctrl and phy */ + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_LOS_LEVEL, 9 << 4); + + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, + IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, + IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, + IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, + IMX6Q_GPR8_TX_SWING_FULL, 127 << 18); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8, + IMX6Q_GPR8_TX_SWING_LOW, 127 << 25); +} + +static void imx6_pcie_host_init(struct pcie_port *pp) +{ + int count = 0; + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + + imx6_pcie_assert_core_reset(pp); + + imx6_pcie_init_phy(pp); + + imx6_pcie_deassert_core_reset(pp); + + dw_pcie_setup_rc(pp); + + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); + + while (!dw_pcie_link_up(pp)) { + mdelay(100); + count++; + if (count >= 10) { + dev_err(pp->dev, "phy link never came up\n"); + dev_dbg(pp->dev,"DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n", + readl(pp->dbi_base + PCIE_PHY_DEBUG_R0), + readl(pp->dbi_base + PCIE_PHY_DEBUG_R1)); + return; + } + } + + return; +} + +static int imx6_pcie_link_up(struct pcie_port *pp) +{ + u32 rc, ltssm, rx_valid, temp; + + /* link is debug bit 36, debug register 1 starts at bit 32 */ + rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32)); + if (rc) + return -1; + + /* From L0, initiate MAC entry to gen2 if EP/RC supports gen2. + * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2). + * If (MAC/LTSSM.state == Recovery.RcvrLock) + * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition + * to gen2 is stuck + */ + pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid); + ltssm = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F; + + if (rx_valid & 0x01) + return 0; + + if (ltssm != 0x0d) + return 0; + + dev_err(pp->dev, + "transition to gen2 is stuck, reset PHY!\n"); + + pcie_phy_read(pp->dbi_base, + PHY_RX_OVRD_IN_LO, &temp); + temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN + | PHY_RX_OVRD_IN_LO_RX_PLL_EN); + pcie_phy_write(pp->dbi_base, + PHY_RX_OVRD_IN_LO, temp); + + usleep_range(2000, 3000); + + pcie_phy_read(pp->dbi_base, + PHY_RX_OVRD_IN_LO, &temp); + temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN + | PHY_RX_OVRD_IN_LO_RX_PLL_EN); + pcie_phy_write(pp->dbi_base, + PHY_RX_OVRD_IN_LO, temp); + + return 0; +} + +static struct pcie_host_ops imx6_pcie_host_ops = { + .link_up = imx6_pcie_link_up, + .host_init = imx6_pcie_host_init, +}; + +static int add_pcie_port(struct pcie_port *pp, struct platform_device *pdev) +{ + int ret; + + pp->irq = platform_get_irq(pdev, 0); + if (!pp->irq) { + dev_err(&pdev->dev, "failed to get irq\n"); + return -ENODEV; + } + + pp->root_bus_nr = -1; + pp->ops = &imx6_pcie_host_ops; + + spin_lock_init(&pp->conf_lock); + ret = dw_pcie_host_init(pp); + if (ret) { + dev_err(&pdev->dev, "failed to initialize host\n"); + return ret; + } + + return 0; +} + +static int __init imx6_pcie_probe(struct platform_device *pdev) +{ + struct imx6_pcie *imx6_pcie; + struct pcie_port *pp; + struct device_node *np = pdev->dev.of_node; + struct resource *dbi_base; + int ret; + + imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), + GFP_KERNEL); + if (!imx6_pcie) + return -ENOMEM; + + pp = &imx6_pcie->pp; + pp->dev = &pdev->dev; + + dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!dbi_base) { + dev_err(&pdev->dev, "dbi_base memory resource not found\n"); + return -ENODEV; + } + + pp->dbi_base = devm_request_and_ioremap(&pdev->dev, dbi_base); + if (IS_ERR(pp->dbi_base)) { + dev_err(&pdev->dev, "unable to remap dbi_base\n"); + ret = PTR_ERR(pp->dbi_base); + goto err; + } + + /* Fetch GPIOs */ + imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0); + if (gpio_is_valid(imx6_pcie->reset_gpio)) { + ret = devm_gpio_request_one(&pdev->dev, + imx6_pcie->reset_gpio, + GPIOF_OUT_INIT_LOW, + "PCIe reset"); + if (ret) { + dev_err(&pdev->dev, "unable to get reset line\n"); + goto err; + } + } + + imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0); + if (gpio_is_valid(imx6_pcie->power_on_gpio)) + devm_gpio_request_one(&pdev->dev, imx6_pcie->power_on_gpio, + GPIOF_OUT_INIT_LOW, + "PCIe power enable"); + + imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0); + if (gpio_is_valid(imx6_pcie->wake_up_gpio)) + devm_gpio_request_one(&pdev->dev, imx6_pcie->wake_up_gpio, + GPIOF_IN, + "PCIe wake up"); + + imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0); + if (gpio_is_valid(imx6_pcie->disable_gpio)) + devm_gpio_request_one(&pdev->dev, imx6_pcie->disable_gpio, + GPIOF_OUT_INIT_HIGH, + "PCIe disable endpoint"); + + /* Fetch clocks */ + imx6_pcie->lvds1_sel = clk_get(&pdev->dev, "lvds1_sel"); + if (IS_ERR(imx6_pcie->lvds1_sel)) { + dev_err(&pdev->dev, + "lvds1_sel clock missing or invalid\n"); + ret = PTR_ERR(imx6_pcie->lvds1_sel); + goto err; + } + + imx6_pcie->lvds1_gate = clk_get(&pdev->dev, "lvds1_gate"); + if (IS_ERR(imx6_pcie->lvds1_gate)) { + dev_err(&pdev->dev, + "lvds1_gate clock select missing or invalid\n"); + ret = PTR_ERR(imx6_pcie->lvds1_gate); + goto err; + } + + imx6_pcie->pcie_ref_125m = clk_get(&pdev->dev, "pcie_ref_125m"); + if (IS_ERR(imx6_pcie->pcie_ref_125m)) { + dev_err(&pdev->dev, + "pcie_ref_125m clock source missing or invalid\n"); + ret = PTR_ERR(imx6_pcie->pcie_ref_125m); + goto err; + } + + imx6_pcie->pcie_axi = clk_get(&pdev->dev, "pcie_axi"); + if (IS_ERR(imx6_pcie->pcie_axi)) { + dev_err(&pdev->dev, + "pcie_axi clock source missing or invalid\n"); + ret = PTR_ERR(imx6_pcie->pcie_axi); + goto err; + } + + imx6_pcie->sata_ref = clk_get(&pdev->dev, "sata_ref"); + if (IS_ERR(imx6_pcie->sata_ref)) { + dev_err(&pdev->dev, + "sata_ref clock source missing or invalid\n"); + ret = PTR_ERR(imx6_pcie->sata_ref); + goto err; + } + + /* Grab GPR config register range */ + imx6_pcie->iomuxc_gpr = + syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr"); + if (IS_ERR(imx6_pcie->iomuxc_gpr)) { + dev_err(&pdev->dev, "unable to find iomuxc registers\n"); + ret = PTR_ERR(imx6_pcie->iomuxc_gpr); + goto err; + } + + ret = add_pcie_port(pp, pdev); + if (ret < 0) + goto err; + + platform_set_drvdata(pdev, imx6_pcie); + return 0; + +err: + return ret; +} + +static int __exit imx6_pcie_remove(struct platform_device *pdev) +{ + struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev); + + clk_disable_unprepare(imx6_pcie->pcie_axi); + clk_disable_unprepare(imx6_pcie->lvds1_gate); + clk_disable_unprepare(imx6_pcie->pcie_ref_125m); + + return 0; +} + +static const struct of_device_id imx6_pcie_of_match[] = { + { .compatible = "fsl,imx6-pcie", }, + {}, +}; +MODULE_DEVICE_TABLE(of, imx6_pcie_of_match); + +static struct platform_driver imx6_pcie_driver = { + .remove = __exit_p(imx6_pcie_remove), + .driver = { + .name = "imx6-pcie", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(imx6_pcie_of_match), + }, +}; + +/* Freescale PCIe driver does not allow module unload */ + +static int __init pcie_init(void) +{ + return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe); +} +subsys_initcall(pcie_init); + +MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>"); +MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver"); +MODULE_LICENSE("GPL v2");
Add support for the PCIe port present on the i.MX6 family of controllers. These use the Synopsis Designware core tied to their own PHY. Signed-off-by: Sean Cross <xobs@kosagi.com> --- .../devicetree/bindings/pci/designware-pcie.txt | 5 + arch/arm/boot/dts/imx6qdl.dtsi | 18 + arch/arm/mach-imx/Kconfig | 2 + drivers/pci/host/Kconfig | 6 + drivers/pci/host/Makefile | 1 + drivers/pci/host/pci-imx6.c | 549 ++++++++++++++++++++ 6 files changed, 581 insertions(+) create mode 100644 drivers/pci/host/pci-imx6.c