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SubjectRE: [PATCH 3/3] PCI: imx: Add support for i.MX8MQ
Date
Hi Andrey:
Thanks for your patch-set.
I have comment about the L1SS implementation below.
It's better to figure out one method to fix it.

BR
Richard

> -----Original Message-----
> From: Andrey Smirnov [mailto:andrew.smirnov@gmail.com]
> Sent: 2018年11月18日 2:12
> To: linux-kernel@vger.kernel.org
> Cc: Andrey Smirnov <andrew.smirnov@gmail.com>; bhelgaas@google.com;
> Fabio Estevam <fabio.estevam@nxp.com>; cphealy@gmail.com;
> l.stach@pengutronix.de; Leonard Crestez <leonard.crestez@nxp.com>;
> Aisheng DONG <aisheng.dong@nxp.com>; Richard Zhu
> <hongxing.zhu@nxp.com>; dl-linux-imx <linux-imx@nxp.com>;
> linux-arm-kernel@lists.infradead.org; linux-pci@vger.kernel.org
> Subject: [PATCH 3/3] PCI: imx: Add support for i.MX8MQ
>
> Cc: bhelgaas@google.com
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> Cc: cphealy@gmail.com
> Cc: l.stach@pengutronix.de
> Cc: Leonard Crestez <leonard.crestez@nxp.com>
> Cc: "A.s. Dong" <aisheng.dong@nxp.com>
> Cc: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: linux-imx@nxp.com
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-pci@vger.kernel.org
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---
> drivers/pci/controller/dwc/Kconfig | 2 +-
> drivers/pci/controller/dwc/pci-imx6.c | 117 ++++++++++++++++++++++++--
> 2 files changed, 113 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/Kconfig
> b/drivers/pci/controller/dwc/Kconfig
> index 91b0194240a5..2b139acccf32 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -90,7 +90,7 @@ config PCI_EXYNOS
>
> config PCI_IMX6
> bool "Freescale i.MX6 PCIe controller"
> - depends on SOC_IMX6Q || (ARM && COMPILE_TEST)
> + depends on SOC_IMX8MQ || SOC_IMX6Q || (ARM && COMPILE_TEST)
> depends on PCI_MSI_IRQ_DOMAIN
> select PCIE_DW_HOST
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index 3c3002861d25..8d1f310e41a6 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -8,6 +8,7 @@
> * Author: Sean Cross <xobs@kosagi.com>
> */
>
> +#include <linux/bitfield.h>
> #include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/gpio.h>
> @@ -30,6 +31,14 @@
>
> #include "pcie-designware.h"
>
> +#define IMX8MQ_PCIE_LINK_CAP_REG_OFFSET 0x7C
> +#define IMX8MQ_PCIE_LINK_CAP_L1EL_64US (0x6 << 15)
> +
> +#define IMX8MQ_GPR_PCIE_REF_USE_PAD BIT(9)
> +#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN BIT(10)
> +#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE BIT(11)
> +
> +
> #define to_imx6_pcie(x) dev_get_drvdata((x)->dev)
>
> enum imx6_pcie_variants {
> @@ -37,6 +46,7 @@ enum imx6_pcie_variants {
> IMX6SX,
> IMX6QP,
> IMX7D,
> + IMX8MQ,
> };
>
> struct imx6_pcie {
> @@ -48,8 +58,10 @@ struct imx6_pcie {
> struct clk *pcie_inbound_axi;
> struct clk *pcie;
> struct regmap *iomuxc_gpr;
> + u32 gpr1x;
> struct reset_control *pciephy_reset;
> struct reset_control *apps_reset;
> + struct reset_control *apps_clk_req;
> struct reset_control *turnoff_reset;
> enum imx6_pcie_variants variant;
> u32 tx_deemph_gen1;
> @@ -59,6 +71,7 @@ struct imx6_pcie {
> u32 tx_swing_low;
> int link_gen;
> struct regulator *vpcie;
> + u32 device_type[2];
> };
>
> /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */ @@
> -245,7 +258,8 @@ static void imx6_pcie_reset_phy(struct imx6_pcie
> *imx6_pcie) {
> u32 tmp;
>
> - if (imx6_pcie->variant == IMX7D)
> + if (imx6_pcie->variant == IMX7D ||
> + imx6_pcie->variant == IMX8MQ)
> return;
>
> pcie_phy_read(imx6_pcie, PHY_RX_OVRD_IN_LO, &tmp); @@ -261,6
> +275,7 @@ static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
> pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp); }
>
> +#ifdef CONFIG_ARM
> /* Added for PCI abort handling */
> static int imx6q_pcie_abort_handler(unsigned long addr,
> unsigned int fsr, struct pt_regs *regs) @@ -294,6 +309,7 @@ static
> int imx6q_pcie_abort_handler(unsigned long addr,
>
> return 1;
> }
> +#endif
>
> static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> { @@ -301,6 +317,7 @@ static void imx6_pcie_assert_core_reset(struct
> imx6_pcie *imx6_pcie)
>
> switch (imx6_pcie->variant) {
> case IMX7D:
> + case IMX8MQ: /* FALLTHROUGH */
> reset_control_assert(imx6_pcie->pciephy_reset);
> reset_control_assert(imx6_pcie->apps_reset);
> break;
> @@ -369,6 +386,18 @@ static int imx6_pcie_enable_ref_clk(struct
> imx6_pcie *imx6_pcie)
> break;
> case IMX7D:
> break;
> + case IMX8MQ:
> + /*
> + * Set the over ride low and enabled
> + * make sure that REF_CLK is turned on.
> + */
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
> + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
> + 0);
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
> + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
> + break;
> }
>
> return ret;
> @@ -397,6 +426,7 @@ static void imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie) {
> struct dw_pcie *pci = imx6_pcie->pci;
> struct device *dev = pci->dev;
> + unsigned int val;
> int ret;
>
> if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) { @@
> -445,6 +475,29 @@ static void imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie)
> }
>
> switch (imx6_pcie->variant) {
> + case IMX8MQ:
> + reset_control_deassert(imx6_pcie->pciephy_reset);
> + udelay(100);
> + /*
> + * Configure the CLK_REQ# high, let the L1SS
> + * automatically controlled by HW.
> + */
> + reset_control_assert(imx6_pcie->apps_clk_req);
> +
> + /*
> + * Configure the L1 latency of rc to less than 64us
> + * Otherwise, the L1/L1SUB wouldn't be enable by ASPM.
> + */
> + val = dw_pcie_readl_dbi(imx6_pcie->pci,
> + SZ_1M +
> + IMX8MQ_PCIE_LINK_CAP_REG_OFFSET);
> + val &= ~PCI_EXP_LNKCAP_L1EL;
> + val |= IMX8MQ_PCIE_LINK_CAP_L1EL_64US;
> + dw_pcie_writel_dbi(imx6_pcie->pci,
> + SZ_1M +
> + IMX8MQ_PCIE_LINK_CAP_REG_OFFSET,
> + val);
> + break;
> case IMX7D:
> reset_control_deassert(imx6_pcie->pciephy_reset);
> imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
> @@ -483,6 +536,15 @@ static void imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie) static void imx6_pcie_init_phy(struct imx6_pcie
> *imx6_pcie) {
> switch (imx6_pcie->variant) {
> + case IMX8MQ:
> + /*
> + * TODO: Currently this code assumes external
> + * oscillator is being used
> + */
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
> + IMX8MQ_GPR_PCIE_REF_USE_PAD,
> + IMX8MQ_GPR_PCIE_REF_USE_PAD);
> + break;
> case IMX7D:
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0); @@
> -519,7 +581,8 @@ static void imx6_pcie_init_phy(struct imx6_pcie
> *imx6_pcie)
> }
>
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> - IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT <<
> 12);
> + imx6_pcie->device_type[0],
> + imx6_pcie->device_type[1]);
> }
>
> static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie) @@ -528,7
> +591,8 @@ static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
> int mult, div;
> u32 val;
>
> - if (imx6_pcie->variant == IMX7D)
> + if (imx6_pcie->variant == IMX7D ||
> + imx6_pcie->variant == IMX8MQ)
> return 0;
>
> switch (phy_rate) {
> @@ -616,6 +680,7 @@ static void imx6_pcie_ltssm_enable(struct device
> *dev)
> IMX6Q_GPR12_PCIE_CTL_2);
> break;
> case IMX7D:
> + case IMX8MQ: /* FALLTHROUGH */
> reset_control_deassert(imx6_pcie->apps_reset);
> break;
> }
> @@ -798,10 +863,24 @@ static void imx6_pcie_clk_disable(struct imx6_pcie
> *imx6_pcie)
> clk_disable_unprepare(imx6_pcie->pcie_phy);
> clk_disable_unprepare(imx6_pcie->pcie_bus);
>
> - if (imx6_pcie->variant == IMX7D) {
> + switch (imx6_pcie->variant) {
> + case IMX7D:
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
> IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
> + break;
> + /*
> + * Disable the override. Configure the CLK_REQ# high, let the
> + * L1SS automatically controlled by HW when link is up.
> + * Otherwise, turn off the REF_CLK to save power consumption.
> + */
[Richard Zhu] About the L1SS support, there is a back-compatible issue.
When one none-L1SS capability EP device is used in one HW design solution.
In this case, EP device wouldn't manipulated its own CLK_REQ#.
The CLK_REQ# would be high when the override_en is disabled here.
That means the REFCLK would be turned off abnormally.
System would have problem when the REFCLK of PCIe is turned off abnormally after link is up.


> + case IMX8MQ:
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
> + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> + 0);
> + break;
> + default:
> + break;
> }
> }
>
> @@ -870,6 +949,10 @@ static int imx6_pcie_probe(struct platform_device
> *pdev)
> imx6_pcie->variant =
> (enum imx6_pcie_variants)of_device_get_match_data(dev);
>
> + imx6_pcie->device_type[0] = IMX6Q_GPR12_DEVICE_TYPE;
> + imx6_pcie->device_type[1] = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE,
> + PCI_EXP_TYPE_ROOT_PORT);
> +
> dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
> if (IS_ERR(pci->dbi_base))
> @@ -921,7 +1004,28 @@ static int imx6_pcie_probe(struct platform_device
> *pdev)
> return PTR_ERR(imx6_pcie->pcie_inbound_axi);
> }
> break;
> - case IMX7D:
> + case IMX8MQ:
> + if (of_property_read_u32(node, "fsl,iomux-gpr1x",
> + &imx6_pcie->gpr1x)) {
> + dev_err(dev, "Failed to get GPR1x address\n");
> + return -EINVAL;
> + }
> +
> + if (of_property_read_u32_array(
> + node, "fsl,gpr12-device-type",
> + imx6_pcie->device_type,
> + ARRAY_SIZE(imx6_pcie->device_type))) {
> + dev_err(dev, "Failed to get device type mask/value\n");
> + return -EINVAL;
> + }
> +
> + imx6_pcie->apps_clk_req =
> + devm_reset_control_get_exclusive(dev, "clkreq");
> + if (IS_ERR(imx6_pcie->apps_clk_req)) {
> + dev_err(dev, "Failed to get PCIE APPS CLK_REQ# reset
> control\n");
> + return PTR_ERR(imx6_pcie->apps_clk_req);
> + }
> + case IMX7D: /* FALLTHROUGH */
> imx6_pcie->pciephy_reset =
> devm_reset_control_get_exclusive(dev,
> "pciephy");
> if (IS_ERR(imx6_pcie->pciephy_reset)) { @@ -1011,6 +1115,7 @@
> static const struct of_device_id imx6_pcie_of_match[] = {
> { .compatible = "fsl,imx6sx-pcie", .data = (void *)IMX6SX, },
> { .compatible = "fsl,imx6qp-pcie", .data = (void *)IMX6QP, },
> { .compatible = "fsl,imx7d-pcie", .data = (void *)IMX7D, },
> + { .compatible = "fsl,imx8mq-pcie", .data = (void *)IMX8MQ, } ,
> {},
> };
>
> @@ -1027,6 +1132,7 @@ static struct platform_driver imx6_pcie_driver = {
>
> static int __init imx6_pcie_init(void)
> {
> +#ifdef CONFIG_ARM
> /*
> * Since probe() can be deferred we need to make sure that
> * hook_fault_code is not called after __init memory is freed @@
> -1036,6 +1142,7 @@ static int __init imx6_pcie_init(void)
> */
> hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
> "external abort on non-linefetch");
> +#endif
>
> return platform_driver_register(&imx6_pcie_driver);
> }
> --
> 2.19.1

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