On 16/9/13 2:06 PM, Shawn Guo wrote:
On Fri, Sep 13, 2013 at 09:40:22AM +0000, Sean Cross wrote:
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@xxxxxxxxxx>
---
.../devicetree/bindings/pci/designware-pcie.txt | 5 +
arch/arm/boot/dts/imx6qdl.dtsi | 16 +
arch/arm/mach-imx/Kconfig | 2 +
arch/arm/mach-imx/clk-imx6q.c | 11 +
drivers/pci/host/Kconfig | 6 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-imx6.c | 482 ++++++++++++++++++++
7 files changed, 523 insertions(+)
create mode 100644 drivers/pci/host/pci-imx6.c
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..ec72271 100644
--- a/arch/arm/boot/dts/imx6qdl.dtsi
+++ b/arch/arm/boot/dts/imx6qdl.dtsi
@@ -116,6 +116,22 @@
arm,data-latency = <4 2 3>;
};
+ pcie: pcie@0x01000000 {
+ compatible = "fsl,imx6-pcie", "snps,dw-pcie";
We generally use particular SoC name to specify the compatible string.
So "fsl,imx6q-pcie" will be more appropriate.
Any reason to specify imx6q in particular? It's also present on the
imx6d, imx6dl, and imx6s (basically, everything but the imx6sl).
/* Set initial power mode */
imx6q_set_lpm(WAIT_CLOCKED);
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..a3f9053
--- /dev/null
+++ b/drivers/pci/host/pci-imx6.c
@@ -0,0 +1,482 @@
+/*
+ * PCIe host controller driver for Freescale i.MX6 SoCs
+ *
+ * Copyright (C) 2013 Kosagi
+ * http://www.kosagi.com
+ *
+ * Author: Sean Cross <xobs@xxxxxxxxxx>
+ *
+ * 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/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 pcie_port pp;
+ struct regmap *iomuxc_gpr;
+ void __iomem *mem_base;
+};
+
+/* 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)
(1 << 5), please.
+#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1<<3)
Ditto
+
+static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
+{
+ u32 val;
+ u32 max_iterations = 10;
+ u32 wait_counter = 0;
+
+ do {
+ val = readl(dbi_base + PCIE_PHY_STAT);
+ val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
+ wait_counter++;
+ udelay(1);
+ } while ((wait_counter < max_iterations) && (val != exp_val));
+
+ if (val != exp_val)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
+{
+ u32 val;
+ int ret;
+
+ 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);
+
+ ret = pcie_phy_poll_ack(dbi_base, 1);
+ if (ret)
+ return ret;
+
+ val = addr << PCIE_PHY_CTRL_DATA_LOC;
+ writel(val, dbi_base + PCIE_PHY_CTRL);
+
+ ret = pcie_phy_poll_ack(dbi_base, 0);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
+static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
+{
+ u32 val, phy_ctl;
+ int ret;
+
+ ret = pcie_phy_wait_ack(dbi_base, addr);
+ if (ret)
+ return ret;
+
+ /* assert Read signal */
+ phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
+ writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
+
+ ret = pcie_phy_poll_ack(dbi_base, 1);
+ if (ret)
+ return ret;
+
+ val = readl(dbi_base + PCIE_PHY_STAT);
+ *data = (val & (0xffff << PCIE_PHY_STAT_DATA_LOC));
One unnecessary parentheses.
+
+ /* deassert Read signal */
+ writel(0x00, dbi_base + PCIE_PHY_CTRL);
+
+ ret = pcie_phy_poll_ack(dbi_base, 0);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
+{
+ u32 var;
+ int ret;
+
+ /* write addr */
+ /* cap addr */
+ ret = pcie_phy_wait_ack(dbi_base, addr);
+ if (ret)
+ return ret;
+
+ 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);
+
+ ret = pcie_phy_poll_ack(dbi_base, 1);
+ if (ret)
+ return ret;
+
+ /* deassert cap data */
+ var = data << PCIE_PHY_CTRL_DATA_LOC;
+ writel(var, dbi_base + PCIE_PHY_CTRL);
+
+ /* wait for ack de-assetion */
+ ret = pcie_phy_poll_ack(dbi_base, 0);
+ if (ret)
+ return ret;
+
+ /* assert wr signal */
+ var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
+ writel(var, dbi_base + PCIE_PHY_CTRL);
+
+ /* wait for ack */
+ ret = pcie_phy_poll_ack(dbi_base, 1);
+ if (ret)
+ return ret;
+
+ /* deassert wr signal */
+ var = data << PCIE_PHY_CTRL_DATA_LOC;
+ writel(var, dbi_base + PCIE_PHY_CTRL);
+
+ /* wait for ack de-assetion */
+ ret = pcie_phy_poll_ack(dbi_base, 0);
+ if (ret)
+ return ret;
+
+ 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);
Nit: have a blank line here.
+ 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)
+{
+ struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+
+ if (gpio_is_valid(imx6_pcie->power_on_gpio))
+ gpio_set_value(imx6_pcie->power_on_gpio, 1);
+
+ 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);
+
+ /* allow the clocks to stabilize */
+ usleep_range(100, 200);
+
+ return 0;
+}
+
+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 */
Why cannot this be fixed right now?
The FIXME is left over from an earlier incarnation. I don't think it's
relevant anymore. I'll drop it.
+ 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)) {
+ usleep_range(100, 1000);
+ 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));
+ break;
+ }
+ }
+
+ 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 -EAGAIN;
+
+ /* 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
+ */
/*
* Multiple lines comment
* ...
*/
+ 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)
imx6_pcie_add_port to have the proper namespace?
I thought this was the style for pci drivers, because
+{
+ 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;
+ }
See kerneldoc of devm_request_and_ioremap(). I believe that the help
already takes care of printing error messages.
This is a very good catch. devm_request_and_ioremap() is deprecated and
in the process of getting removed. I'll replace the call and see what's
best in terms of error messages.
+
+ /* 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 gpio\n");
+ goto err;
+ }
+ }
The reset-gpio is not optional but required. So if we do not have a
valid reset-gpio, the probe should fail. And that's why we can access
reset_gpio in imx6_pcie_assert_core_reset() without checking if it's
valid.
That is a very good call. I'll make the reset-gpio actually required.
+
+ imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);
+ if (gpio_is_valid(imx6_pcie->power_on_gpio)) {
+ ret = devm_gpio_request_one(&pdev->dev,
+ imx6_pcie->power_on_gpio,
+ GPIOF_OUT_INIT_LOW,
+ "PCIe power enable");
+ if (ret) {
+ dev_err(&pdev->dev, "unable to get power-on gpio\n");
+ goto err;
+ }
+ }
+
+ imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0);
+ if (gpio_is_valid(imx6_pcie->wake_up_gpio)) {
+ ret = devm_gpio_request_one(&pdev->dev,
+ imx6_pcie->wake_up_gpio,
+ GPIOF_IN,
+ "PCIe wake up");
+ if (ret) {
+ dev_err(&pdev->dev, "unable to get wake-up gpio\n");
+ goto err;
+ }
+ }
+
+ imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0);
+ if (gpio_is_valid(imx6_pcie->disable_gpio)) {
+ ret = devm_gpio_request_one(&pdev->dev,
+ imx6_pcie->disable_gpio,
+ GPIOF_OUT_INIT_HIGH,
+ "PCIe disable endpoint");
+ if (ret) {
+ dev_err(&pdev->dev, "unable to get disable-ep gpio\n");
+ 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 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 = {
+ .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);
Any reason why it cannot be module_init()?
No reason whatsoever. I'll rename pcie_init to module_init.
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