[PATCH 3/5] PCI: st: Provide support for the sti PCIe controller

[Gabriel FERNANDEZ]

sti pcie is built around a Synopsis Designware PCIe IP.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxxxxxx>
---
 drivers/pci/host/Kconfig  |   9 +
 drivers/pci/host/Makefile |   1 +
 drivers/pci/host/pci-st.c | 583 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 593 insertions(+)
 create mode 100644 drivers/pci/host/pci-st.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 7b892a9..af9f9212 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -106,4 +106,13 @@ config PCI_VERSATILE
 	bool "ARM Versatile PB PCI controller"
 	depends on ARCH_VERSATILE
 
+config PCI_ST
+	bool "ST PCIe controller"
+	depends on ARCH_STI || (ARM && COMPILE_TEST)
+	select PCIE_DW
+	help
+	  Enable PCIe controller support on ST Socs. This controller is based
+	  on Designware hardware and therefore the driver re-uses the
+	  Designware core functions to implement the driver.
+
 endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index e61d91c..97c6622 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
 obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
 obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
 obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
+obj-$(CONFIG_PCI_ST) += pci-st.o
diff --git a/drivers/pci/host/pci-st.c b/drivers/pci/host/pci-st.c
new file mode 100644
index 0000000..1ff5ce2
--- /dev/null
+++ b/drivers/pci/host/pci-st.c
@@ -0,0 +1,583 @@
+/*
+ * Copyright (C) 2014 STMicroelectronics
+ *
+ * STMicroelectronics PCI express Driver for sti SoCs.
+ * ST PCIe IPs are built around a Synopsys IP Core.
+ *
+ * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
+ *
+ * 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/interrupt.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include "pcie-designware.h"
+
+#define TRANSLATION_CONTROL		0x900
+/* Controls if area is inclusive or exclusive */
+#define RC_PASS_ADDR_RANGE		BIT(1)
+
+/* Base of area reserved for config accesses. Fixed size of 64K. */
+#define CFG_BASE_ADDRESS		0x92c
+#define CFG_REGION_SIZE			65536
+#define CFG_SPACE1_OFFSET		0x1000
+
+/* First 4K of config space has this BDF (bus,device,function) */
+#define FUNC0_BDF_NUM			0x930
+
+/* Mem regions */
+#define IN0_MEM_ADDR_START		0x964
+#define IN0_MEM_ADDR_LIMIT		0x968
+#define IN1_MEM_ADDR_START		0x974
+#define IN1_MEM_ADDR_LIMIT		0x978
+
+/* This actually contains the LTSSM state machine state */
+#define PORT_LOGIC_DEBUG_REG_0		0x728
+
+/* LTSSM state machine values	*/
+#define DEBUG_REG_0_LTSSM_MASK		0x1f
+#define S_DETECT_QUIET			0x00
+#define S_DETECT_ACT			0x01
+#define S_POLL_ACTIVE			0x02
+#define S_POLL_COMPLIANCE		0x03
+#define S_POLL_CONFIG			0x04
+#define S_PRE_DETECT_QUIET		0x05
+#define S_DETECT_WAIT			0x06
+#define S_CFG_LINKWD_START		0x07
+#define S_CFG_LINKWD_ACEPT		0x08
+#define S_CFG_LANENUM_WAIT		0x09
+#define S_CFG_LANENUM_ACEPT		0x0A
+#define S_CFG_COMPLETE			0x0B
+#define S_CFG_IDLE			0x0C
+#define S_RCVRY_LOCK			0x0D
+#define S_RCVRY_SPEED			0x0E
+#define S_RCVRY_RCVRCFG			0x0F
+#define S_RCVRY_IDLE			0x10
+#define S_L0				0x11
+#define S_L0S				0x12
+#define S_L123_SEND_EIDLE		0x13
+#define S_L1_IDLE			0x14
+#define S_L2_IDLE			0x15
+#define S_L2_WAKE			0x16
+#define S_DISABLED_ENTRY		0x17
+#define S_DISABLED_IDLE			0x18
+#define S_DISABLED			0x19
+#define S_LPBK_ENTRY			0x1A
+#define S_LPBK_ACTIVE			0x1B
+#define S_LPBK_EXIT			0x1C
+#define S_LPBK_EXIT_TIMEOUT		0x1D
+#define S_HOT_RESET_ENTRY		0x1E
+#define S_HOT_RESET			0x1F
+
+/* syscfg bits */
+#define PCIE_SYS_INT			BIT(5)
+#define PCIE_APP_REQ_RETRY_EN		BIT(3)
+#define PCIE_APP_LTSSM_ENABLE		BIT(2)
+#define PCIE_APP_INIT_RST		BIT(1)
+#define PCIE_DEVICE_TYPE		BIT(0)
+#define PCIE_DEFAULT_VAL		PCIE_DEVICE_TYPE
+
+/* Time to wait between testing the link in msecs (hardware poll interval) */
+#define LINK_LOOP_DELAY_MS 1
+/* Total amount of time to wait for the link to come up in msecs */
+#define LINK_WAIT_MS 120
+#define LINK_LOOP_COUNT (LINK_WAIT_MS / LINK_LOOP_DELAY_MS)
+
+/* st,syscfg offsets */
+#define SYSCFG0_REG	1
+#define SYSCFG1_REG	2
+
+#define to_st_pcie(x)	container_of(x, struct st_pcie, pp)
+
+/**
+ * struct st_pcie - private data of the controller
+ * @pp: designware pcie port
+ * @syscfg0: PCIe configuration 0 register, regmap offset
+ * @syscfg1: PCIe configuration 1 register, regmap offset
+ * @phy: associated pcie phy
+ * @lmi: memory made available to the controller
+ * @regmap: Syscfg registers bank in which PCIe port is configured
+ * @pwr: power control
+ * @rst: reset control
+ * @reset_gpio: optional reset gpio
+ * @config_window_start: start address of 64K config space area
+ */
+struct st_pcie {
+	struct pcie_port pp;
+	int syscfg0;
+	int syscfg1;
+	struct phy *phy;
+	struct resource	*lmi;
+	struct regmap *regmap;
+	struct reset_control *pwr;
+	struct reset_control *rst;
+	int reset_gpio;
+	phys_addr_t config_window_start;
+};
+
+/*
+ * Function to test if the link is in an operational state or not. We must
+ * ensure the link is operational before we try to do a configuration access.
+ */
+static int st_pcie_link_up(struct pcie_port *pp)
+{
+	u32 status;
+	int link_up;
+	int count = 0;
+
+	/*
+	 * We have to be careful here. This is used in config read/write,
+	 * The higher levels switch off interrupts, so you cannot use
+	 * jiffies to do a timeout, or reschedule
+	 */
+	do {
+		/*
+		 * What about L2? I think software intervention is
+		 * required to get it out of L2, so in effect the link
+		 * is down. Requires more work when/if we implement power
+		 * management
+		 */
+		status = readl_relaxed(pp->dbi_base + PORT_LOGIC_DEBUG_REG_0);
+		status &= DEBUG_REG_0_LTSSM_MASK;
+
+		link_up = (status == S_L0) || (status == S_L0S) ||
+			  (status == S_L1_IDLE);
+
+		/*
+		 * It can take some considerable time for the link to actually
+		 * come up, caused by the PLLs. Experiments indicate it takes
+		 * about 8ms to actually bring the link up, but this can vary
+		 * considerably according to the specification. This code should
+		 * allow sufficient time
+		 */
+		if (!link_up)
+			mdelay(LINK_LOOP_DELAY_MS);
+
+	} while (!link_up && ++count < LINK_LOOP_COUNT);
+
+	return link_up;
+}
+
+/*
+ * On ARM platforms, we actually get a bus error returned when the PCIe IP
+ * returns a UR or CRS instead of an OK.
+ */
+static int st_pcie_abort_handler(unsigned long addr, unsigned int fsr,
+				 struct pt_regs *regs)
+{
+	return 0;
+}
+
+/*
+ * The PCI express core IP expects the following arrangement on it's address
+ * bus (slv_haddr) when driving config cycles.
+ * bus_number		[31:24]
+ * dev_number		[23:19]
+ * func_number		[18:16]
+ * unused		[15:12]
+ * ext_reg_number	[11:8]
+ * reg_number		[7:2]
+ *
+ * Bits [15:12] are unused.
+ *
+ * In the glue logic there is a 64K region of address space that can be
+ * written/read to generate config cycles. The base address of this is
+ * controlled by CFG_BASE_ADDRESS. There are 8 16 bit registers called
+ * FUNC0_BDF_NUM to FUNC8_BDF_NUM. These split the bottom half of the 64K
+ * window into 8 regions at 4K boundaries. These control the bus,device and
+ * function number you are trying to talk to.
+ *
+ * The decision on whether to generate a type 0 or type 1 access is controlled
+ * by bits 15:12 of the address you write to.  If they are zero, then a type 0
+ * is generated, if anything else it will be a type 1. Thus the bottom 4K
+ * region controlled by FUNC0_BDF_NUM can only generate type 0, all the others
+ * can only generate type 1.
+ *
+ * We only use FUNC0_BDF_NUM and FUNC1_BDF_NUM. Which one you use is selected
+ * by bit 12 of the address you write to. The selected register is then used
+ * for the top 16 bits of the slv_haddr to form the bus/dev/func, bit 15:12 are
+ * wired to zero, and bits 11:2 form the address of the register you want to
+ * read in config space.
+ *
+ * We always write FUNC0_BDF_NUM as a 32 bit write. So if we want type 1
+ * accesses we have to shift by 16 so in effect we are writing to FUNC1_BDF_NUM
+ */
+static inline u32 bdf_num(int bus, int devfn, int is_root_bus)
+{
+	return ((bus << 8) | devfn) << (is_root_bus ? 0 : 16);
+}
+
+static int st_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+				 unsigned int devfn, int where, int size,
+				 u32 *val)
+{
+	int ret;
+	u32 bdf, addr;
+
+	addr = where & ~0x3;
+	bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
+
+	/* Set the config packet devfn */
+	writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
+	readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
+
+	if (bus->parent->number == pp->root_bus_nr)
+		ret = dw_pcie_cfg_read(pp->va_cfg0_base + addr, where, size,
+				       val);
+	else
+		ret = dw_pcie_cfg_read(pp->va_cfg1_base + addr, where, size,
+				       val);
+	return ret;
+}
+
+static int st_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+				 unsigned int devfn, int where, int size,
+				 u32 val)
+{
+	int ret;
+	u32 bdf, addr;
+
+	addr = where & ~0x3;
+	bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
+
+	/* Set the config packet devfn */
+	writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
+	readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
+
+	if (bus->parent->number == pp->root_bus_nr)
+		ret = dw_pcie_cfg_write(pp->va_cfg0_base + addr, where, size,
+					val);
+	else
+		ret = dw_pcie_cfg_write(pp->va_cfg1_base + addr, where, size,
+					val);
+	return ret;
+}
+
+static void st_pcie_board_reset(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+
+	if (!gpio_is_valid(pcie->reset_gpio))
+		return;
+
+	if (gpio_direction_output(pcie->reset_gpio, 0)) {
+		dev_err(pp->dev, "Cannot set PERST# (gpio %u) to output\n",
+			pcie->reset_gpio);
+		return;
+	}
+
+	/* From PCIe spec */
+	msleep(2);
+	gpio_direction_output(pcie->reset_gpio, 1);
+
+	/*
+	 * PCIe specification states that you should not issue any config
+	 * requests until 100ms after asserting reset, so we enforce that here
+	 */
+	msleep(100);
+}
+
+static void st_pcie_hw_setup(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+
+	dw_pcie_setup_rc(pp);
+
+	/* Set up the config window to the top of the PCI address space */
+	writel_relaxed(pcie->config_window_start,
+		       pp->dbi_base + CFG_BASE_ADDRESS);
+
+	/*
+	 * Open up memory to the PCI controller. We could do slightly
+	 * better than this and exclude the kernel text segment and bss etc.
+	 * They are base/limit registers so can be of arbitrary alignment
+	 * presumably
+	 */
+	writel_relaxed(pcie->lmi->start, pp->dbi_base + IN0_MEM_ADDR_START);
+	writel_relaxed(pcie->lmi->end, pp->dbi_base + IN0_MEM_ADDR_LIMIT);
+
+	/* Disable the 2nd region */
+	writel_relaxed(~0, pp->dbi_base + IN1_MEM_ADDR_START);
+	writel_relaxed(0, pp->dbi_base + IN1_MEM_ADDR_LIMIT);
+
+	writel_relaxed(RC_PASS_ADDR_RANGE, pp->dbi_base + TRANSLATION_CONTROL);
+
+	/* Now assert the board level reset to the other PCIe device */
+	st_pcie_board_reset(pp);
+}
+
+static irqreturn_t st_pcie_msi_irq_handler(int irq, void *arg)
+{
+	struct pcie_port *pp = arg;
+
+	return dw_handle_msi_irq(pp);
+}
+
+static int st_pcie_init(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+	int ret;
+
+	ret = reset_control_deassert(pcie->pwr);
+	if (ret) {
+		dev_err(pp->dev, "unable to bring out of powerdown\n");
+		return ret;
+	}
+
+	ret = reset_control_deassert(pcie->rst);
+	if (ret) {
+		dev_err(pp->dev, "unable to bring out of softreset\n");
+		return ret;
+	}
+
+	/* Set device type : Root Complex */
+	ret = regmap_write(pcie->regmap, pcie->syscfg0, PCIE_DEVICE_TYPE);
+	if (ret < 0) {
+		dev_err(pp->dev, "unable to set device type\n");
+		return ret;
+	}
+
+	usleep_range(1000, 2000);
+	return ret;
+}
+
+static int st_pcie_enable_ltssm(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+
+	return regmap_update_bits(pcie->regmap, pcie->syscfg1,
+				  PCIE_APP_LTSSM_ENABLE, PCIE_APP_LTSSM_ENABLE);
+}
+
+static int st_pcie_disable_ltssm(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+
+	return regmap_update_bits(pcie->regmap, pcie->syscfg1,
+				  PCIE_APP_LTSSM_ENABLE, 0);
+}
+
+static void st_pcie_host_init(struct pcie_port *pp)
+{
+	struct st_pcie *pcie = to_st_pcie(pp);
+	int err;
+
+	/*
+	 * We have to initialise the PCIe cell on some hardware before we can
+	 * talk to the phy
+	 */
+	err = st_pcie_init(pp);
+	if (err)
+		return;
+
+	err = st_pcie_disable_ltssm(pp);
+	if (err) {
+		dev_err(pp->dev, "disable ltssm failed, %d\n", err);
+		return;
+	}
+
+	/* Now init the associated miphy */
+	err = phy_init(pcie->phy);
+	if (err < 0) {
+		dev_err(pp->dev, "Cannot init PHY: %d\n", err);
+		return;
+	}
+
+	/* Now do all the register poking */
+	st_pcie_hw_setup(pp);
+
+	/* Re-enable the link */
+	err = st_pcie_enable_ltssm(pp);
+	if (err)
+		dev_err(pp->dev, "enable ltssm failed, %d\n", err);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI))
+		dw_pcie_msi_init(pp);
+}
+
+static struct pcie_host_ops st_pcie_host_ops = {
+	.rd_other_conf = st_pcie_rd_other_conf,
+	.wr_other_conf = st_pcie_wr_other_conf,
+	.link_up = st_pcie_link_up,
+	.host_init = st_pcie_host_init,
+};
+
+static const struct of_device_id st_pcie_of_match[] = {
+	{ .compatible = "st,pcie", },
+	{ },
+};
+
+static int st_pcie_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct st_pcie *pcie;
+	struct device_node *np = pdev->dev.of_node;
+	struct pcie_port *pp;
+	int ret;
+
+	pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
+	if (!pcie)
+		return -ENOMEM;
+
+	memset(pcie, 0, sizeof(*pcie));
+
+	pp = &pcie->pp;
+	pp->dev = &pdev->dev;
+
+	/* mem regions */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+	pp->dbi_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pp->dbi_base))
+		return PTR_ERR(pp->dbi_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
+	if (!res)
+		return -ENXIO;
+
+	/* Check that this has sensible values */
+	if ((resource_size(res) != CFG_REGION_SIZE) ||
+	    (res->start & (CFG_REGION_SIZE - 1))) {
+		dev_err(&pdev->dev, "Invalid config space properties\n");
+		return -EINVAL;
+	}
+	pcie->config_window_start = res->start;
+
+	pp->va_cfg0_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pp->va_cfg0_base))
+		return PTR_ERR(pp->va_cfg0_base);
+	pp->va_cfg1_base = pp->va_cfg0_base + CFG_SPACE1_OFFSET;
+
+	pcie->lmi = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+						 "mem-window");
+	if (!pcie->lmi)
+		return -ENXIO;
+
+	/* regmap registers for PCIe IP configuration */
+	pcie->regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
+	if (IS_ERR(pcie->regmap)) {
+		dev_err(&pdev->dev, "No syscfg phandle specified\n");
+		return PTR_ERR(pcie->regmap);
+	}
+
+	ret = of_property_read_u32_index(np, "st,syscfg", SYSCFG0_REG,
+					 &pcie->syscfg0);
+	if (ret) {
+		dev_err(&pdev->dev, "can't get syscfg0 offset (%d)\n", ret);
+		return ret;
+	}
+
+	ret = of_property_read_u32_index(np, "st,syscfg", SYSCFG1_REG,
+					 &pcie->syscfg1);
+	if (ret) {
+		dev_err(&pdev->dev, "can't get syscfg1 offset (%d)\n", ret);
+		return ret;
+	}
+
+	/* powerdown / resets */
+	pcie->pwr = devm_reset_control_get(&pdev->dev, "powerdown");
+	if (IS_ERR(pcie->pwr)) {
+		dev_err(&pdev->dev, "powerdown reset control not defined\n");
+		return PTR_ERR(pcie->pwr);
+	}
+
+	pcie->rst = devm_reset_control_get(&pdev->dev, "softreset");
+	if (IS_ERR(pcie->rst)) {
+		dev_err(&pdev->dev, "Soft reset control not defined\n");
+		return PTR_ERR(pcie->pwr);
+	}
+
+	/* phy */
+	pcie->phy = devm_phy_get(&pdev->dev, "pcie");
+	if (IS_ERR(pcie->phy)) {
+		dev_err(&pdev->dev, "no PHY configured\n");
+		return PTR_ERR(pcie->phy);
+	}
+
+	/* Claim the GPIO for PRST# if available */
+	pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
+	if (!gpio_is_valid(pcie->reset_gpio))
+		dev_dbg(&pdev->dev, "No reset-gpio configured\n");
+	else {
+		ret = devm_gpio_request(&pdev->dev,
+					pcie->reset_gpio,
+					"PCIe reset");
+		if (ret) {
+			dev_err(&pdev->dev, "Cannot request reset-gpio %d\n",
+				pcie->reset_gpio);
+			return ret;
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		pp->msi_irq = platform_get_irq_byname(pdev, "msi");
+		if (pp->msi_irq <= 0) {
+			dev_err(&pdev->dev, "failed to get MSI irq\n");
+			return -ENODEV;
+		}
+
+		ret = devm_request_irq(&pdev->dev, pp->msi_irq,
+				       st_pcie_msi_irq_handler,
+				       IRQF_SHARED, "st-pcie-msi", pp);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to request MSI irq\n");
+			return -ENODEV;
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_ARM)) {
+		/*
+		 * We have to hook the abort handler so that we can intercept
+		 * bus errors when doing config read/write that return UR,
+		 * which is flagged up as a bus error
+		 */
+		hook_fault_code(16+6, st_pcie_abort_handler, SIGBUS, 0,
+				"imprecise external abort");
+	}
+
+	pp->root_bus_nr = -1;
+	pp->ops = &st_pcie_host_ops;
+
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize host\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pcie);
+
+	dev_info(&pdev->dev, "Initialized\n");
+	return 0;
+}
+
+MODULE_DEVICE_TABLE(of, st_pcie_of_match);
+
+static struct platform_driver st_pcie_driver = {
+	.driver = {
+		.name = "st-pcie",
+		.of_match_table = st_pcie_of_match,
+	},
+};
+
+/* ST PCIe driver does not allow module unload */
+static int __init pcie_init(void)
+{
+	return platform_driver_probe(&st_pcie_driver, st_pcie_probe);
+}
+device_initcall(pcie_init);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@xxxxxx>");
+MODULE_DESCRIPTION("PCI express Driver for ST SoCs");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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