PCI: spear: Add PCIe driver for ST Microelectronics SPEAr13xx

ARM based ST Microelectronics's SPEAr1310 and SPEAr1340 SOCs have onchip
designware PCIe controller. To make that usable, this patch adds a wrapper
driver based on existing designware driver.

Adds bindings for this new driver and update MAINTAINERS as well.

Cc: linux-pci@vger.kernel.org
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Mohit Kumar <mohit.kumar@st.com>
[viresh: fixed logs/cclist/checkpatch warnings, broken into smaller patches]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Documentation/devicetree/bindings/pci/spear13xx-pcie.txt

@@ -0,0 +1,14 @@
+SPEAr13XX PCIe DT detail:
+================================
+
+SPEAr13XX uses synopsis designware PCIe controller and ST MiPHY as phy
+controller.
+
+Required properties:
+- compatible : should be "st,spear1340-pcie", "snps,dw-pcie".
+- phys		    : phandle to phy node associated with pcie controller
+- phy-names	    : must be "pcie-phy"
+- All other definitions as per generic PCI bindings
+
+ Optional properties:
+- st,pcie-is-gen1 indicates that forced gen1 initialization is needed.

MAINTAINERS

@@ -6820,6 +6820,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/pci/host-generic-pci.txt
 F:	drivers/pci/host/pci-host-generic.c
 
+PCIE DRIVER FOR ST SPEAR13XX
+M:	Mohit Kumar <mohit.kumar@st.com>
+L:	linux-pci@vger.kernel.org
+S:	Maintained
+F:	drivers/pci/host/*spear*
+
 PCMCIA SUBSYSTEM
 P:	Linux PCMCIA Team
 L:	linux-pcmcia@lists.infradead.org

drivers/pci/host/Kconfig

@@ -46,4 +46,12 @@ config PCI_HOST_GENERIC
 	  Say Y here if you want to support a simple generic PCI host
 	  controller, such as the one emulated by kvmtool.
 
+config PCIE_SPEAR13XX
+	tristate "STMicroelectronics SPEAr PCIe controller"
+	depends on ARCH_SPEAR13XX
+	select PCIEPORTBUS
+	select PCIE_DW
+	help
+	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
+
 endmenu

drivers/pci/host/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
 obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
 obj-$(CONFIG_PCI_RCAR_GEN2_PCIE) += pcie-rcar.o
 obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
+obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o

drivers/pci/host/pcie-spear13xx.c

@@ -0,0 +1,405 @@
+/*
+ * PCIe host controller driver for ST Microelectronics SPEAr13xx SoCs
+ *
+ * SPEAr13xx PCIe Glue Layer Source Code
+ *
+ * Copyright (C) 2010-2014 ST Microelectronics
+ * Pratyush Anand <pratyush.anand@st.com>
+ * Mohit Kumar <mohit.kumar@st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pci.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/resource.h>
+
+#include "pcie-designware.h"
+
+struct spear13xx_pcie {
+	void __iomem		*app_base;
+	struct phy		*phy;
+	struct clk		*clk;
+	struct pcie_port	pp;
+	bool			is_gen1;
+};
+
+struct pcie_app_reg {
+	u32	app_ctrl_0;		/* cr0 */
+	u32	app_ctrl_1;		/* cr1 */
+	u32	app_status_0;		/* cr2 */
+	u32	app_status_1;		/* cr3 */
+	u32	msg_status;		/* cr4 */
+	u32	msg_payload;		/* cr5 */
+	u32	int_sts;		/* cr6 */
+	u32	int_clr;		/* cr7 */
+	u32	int_mask;		/* cr8 */
+	u32	mst_bmisc;		/* cr9 */
+	u32	phy_ctrl;		/* cr10 */
+	u32	phy_status;		/* cr11 */
+	u32	cxpl_debug_info_0;	/* cr12 */
+	u32	cxpl_debug_info_1;	/* cr13 */
+	u32	ven_msg_ctrl_0;		/* cr14 */
+	u32	ven_msg_ctrl_1;		/* cr15 */
+	u32	ven_msg_data_0;		/* cr16 */
+	u32	ven_msg_data_1;		/* cr17 */
+	u32	ven_msi_0;		/* cr18 */
+	u32	ven_msi_1;		/* cr19 */
+	u32	mst_rmisc;		/* cr20 */
+};
+
+/* CR0 ID */
+#define RX_LANE_FLIP_EN_ID			0
+#define TX_LANE_FLIP_EN_ID			1
+#define SYS_AUX_PWR_DET_ID			2
+#define APP_LTSSM_ENABLE_ID			3
+#define SYS_ATTEN_BUTTON_PRESSED_ID		4
+#define SYS_MRL_SENSOR_STATE_ID			5
+#define SYS_PWR_FAULT_DET_ID			6
+#define SYS_MRL_SENSOR_CHGED_ID			7
+#define SYS_PRE_DET_CHGED_ID			8
+#define SYS_CMD_CPLED_INT_ID			9
+#define APP_INIT_RST_0_ID			11
+#define APP_REQ_ENTR_L1_ID			12
+#define APP_READY_ENTR_L23_ID			13
+#define APP_REQ_EXIT_L1_ID			14
+#define DEVICE_TYPE_EP				(0 << 25)
+#define DEVICE_TYPE_LEP				(1 << 25)
+#define DEVICE_TYPE_RC				(4 << 25)
+#define SYS_INT_ID				29
+#define MISCTRL_EN_ID				30
+#define REG_TRANSLATION_ENABLE			31
+
+/* CR1 ID */
+#define APPS_PM_XMT_TURNOFF_ID			2
+#define APPS_PM_XMT_PME_ID			5
+
+/* CR3 ID */
+#define XMLH_LTSSM_STATE_DETECT_QUIET		0x00
+#define XMLH_LTSSM_STATE_DETECT_ACT		0x01
+#define XMLH_LTSSM_STATE_POLL_ACTIVE		0x02
+#define XMLH_LTSSM_STATE_POLL_COMPLIANCE	0x03
+#define XMLH_LTSSM_STATE_POLL_CONFIG		0x04
+#define XMLH_LTSSM_STATE_PRE_DETECT_QUIET	0x05
+#define XMLH_LTSSM_STATE_DETECT_WAIT		0x06
+#define XMLH_LTSSM_STATE_CFG_LINKWD_START	0x07
+#define XMLH_LTSSM_STATE_CFG_LINKWD_ACEPT	0x08
+#define XMLH_LTSSM_STATE_CFG_LANENUM_WAIT	0x09
+#define XMLH_LTSSM_STATE_CFG_LANENUM_ACEPT	0x0A
+#define XMLH_LTSSM_STATE_CFG_COMPLETE		0x0B
+#define XMLH_LTSSM_STATE_CFG_IDLE		0x0C
+#define XMLH_LTSSM_STATE_RCVRY_LOCK		0x0D
+#define XMLH_LTSSM_STATE_RCVRY_SPEED		0x0E
+#define XMLH_LTSSM_STATE_RCVRY_RCVRCFG		0x0F
+#define XMLH_LTSSM_STATE_RCVRY_IDLE		0x10
+#define XMLH_LTSSM_STATE_L0			0x11
+#define XMLH_LTSSM_STATE_L0S			0x12
+#define XMLH_LTSSM_STATE_L123_SEND_EIDLE	0x13
+#define XMLH_LTSSM_STATE_L1_IDLE		0x14
+#define XMLH_LTSSM_STATE_L2_IDLE		0x15
+#define XMLH_LTSSM_STATE_L2_WAKE		0x16
+#define XMLH_LTSSM_STATE_DISABLED_ENTRY		0x17
+#define XMLH_LTSSM_STATE_DISABLED_IDLE		0x18
+#define XMLH_LTSSM_STATE_DISABLED		0x19
+#define XMLH_LTSSM_STATE_LPBK_ENTRY		0x1A
+#define XMLH_LTSSM_STATE_LPBK_ACTIVE		0x1B
+#define XMLH_LTSSM_STATE_LPBK_EXIT		0x1C
+#define XMLH_LTSSM_STATE_LPBK_EXIT_TIMEOUT	0x1D
+#define XMLH_LTSSM_STATE_HOT_RESET_ENTRY	0x1E
+#define XMLH_LTSSM_STATE_HOT_RESET		0x1F
+#define XMLH_LTSSM_STATE_MASK			0x3F
+#define XMLH_LINK_UP				(1 << 6)
+
+/* CR4 ID */
+#define CFG_MSI_EN_ID				18
+
+/* CR6 */
+#define INTA_CTRL_INT				(1 << 7)
+#define INTB_CTRL_INT				(1 << 8)
+#define INTC_CTRL_INT				(1 << 9)
+#define INTD_CTRL_INT				(1 << 10)
+#define MSI_CTRL_INT				(1 << 26)
+
+/* CR19 ID */
+#define VEN_MSI_REQ_ID				11
+#define VEN_MSI_FUN_NUM_ID			8
+#define VEN_MSI_TC_ID				5
+#define VEN_MSI_VECTOR_ID			0
+#define VEN_MSI_REQ_EN		((u32)0x1 << VEN_MSI_REQ_ID)
+#define VEN_MSI_FUN_NUM_MASK	((u32)0x7 << VEN_MSI_FUN_NUM_ID)
+#define VEN_MSI_TC_MASK		((u32)0x7 << VEN_MSI_TC_ID)
+#define VEN_MSI_VECTOR_MASK	((u32)0x1F << VEN_MSI_VECTOR_ID)
+
+#define EXP_CAP_ID_OFFSET			0x70
+
+#define to_spear13xx_pcie(x)	container_of(x, struct spear13xx_pcie, pp)
+
+static int spear13xx_pcie_establish_link(struct pcie_port *pp)
+{
+	u32 val;
+	int count = 0;
+	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
+	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	u32 exp_cap_off = EXP_CAP_ID_OFFSET;
+
+	if (dw_pcie_link_up(pp)) {
+		dev_err(pp->dev, "link already up\n");
+		return 0;
+	}
+
+	dw_pcie_setup_rc(pp);
+
+	/*
+	 * this controller support only 128 bytes read size, however its
+	 * default value in capability register is 512 bytes. So force
+	 * it to 128 here.
+	 */
+	dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, &val);
+	val &= ~PCI_EXP_DEVCTL_READRQ;
+	dw_pcie_cfg_write(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, val);
+
+	dw_pcie_cfg_write(pp->dbi_base, PCI_VENDOR_ID, 2, 0x104A);
+	dw_pcie_cfg_write(pp->dbi_base, PCI_DEVICE_ID, 2, 0xCD80);
+
+	/*
+	 * if is_gen1 is set then handle it, so that some buggy card
+	 * also works
+	 */
+	if (spear13xx_pcie->is_gen1) {
+		dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCAP, 4,
+				 &val);
+		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
+			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
+			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
+			dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
+					  PCI_EXP_LNKCAP, 4, val);
+		}
+
+		dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCTL2, 4,
+				 &val);
+		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
+			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
+			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
+			dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
+					  PCI_EXP_LNKCTL2, 4, val);
+		}
+	}
+
+	/* enable ltssm */
+	writel(DEVICE_TYPE_RC | (1 << MISCTRL_EN_ID)
+			| (1 << APP_LTSSM_ENABLE_ID)
+			| ((u32)1 << REG_TRANSLATION_ENABLE),
+			&app_reg->app_ctrl_0);
+
+	/* check if the link is up or not */
+	while (!dw_pcie_link_up(pp)) {
+		mdelay(100);
+		count++;
+		if (count == 10) {
+			dev_err(pp->dev, "link Fail\n");
+			return -EINVAL;
+		}
+	}
+	dev_info(pp->dev, "link up\n");
+
+	return 0;
+}
+
+static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
+{
+	struct pcie_port *pp = arg;
+	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
+	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	unsigned int status;
+
+	status = readl(&app_reg->int_sts);
+
+	if (status & MSI_CTRL_INT) {
+		if (!IS_ENABLED(CONFIG_PCI_MSI))
+			BUG();
+		dw_handle_msi_irq(pp);
+	}
+
+	writel(status, &app_reg->int_clr);
+
+	return IRQ_HANDLED;
+}
+
+static void spear13xx_pcie_enable_interrupts(struct pcie_port *pp)
+{
+	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
+	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+
+	/* Enable MSI interrupt */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		dw_pcie_msi_init(pp);
+		writel(readl(&app_reg->int_mask) |
+				MSI_CTRL_INT, &app_reg->int_mask);
+	}
+}
+
+static int spear13xx_pcie_link_up(struct pcie_port *pp)
+{
+	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
+	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+
+	if (readl(&app_reg->app_status_1) & XMLH_LINK_UP)
+		return 1;
+
+	return 0;
+}
+
+static void spear13xx_pcie_host_init(struct pcie_port *pp)
+{
+	spear13xx_pcie_establish_link(pp);
+	spear13xx_pcie_enable_interrupts(pp);
+}
+
+static struct pcie_host_ops spear13xx_pcie_host_ops = {
+	.link_up = spear13xx_pcie_link_up,
+	.host_init = spear13xx_pcie_host_init,
+};
+
+static int add_pcie_port(struct pcie_port *pp, struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	pp->irq = platform_get_irq(pdev, 0);
+	if (!pp->irq) {
+		dev_err(dev, "failed to get irq\n");
+		return -ENODEV;
+	}
+	ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
+			       IRQF_SHARED, "spear1340-pcie", pp);
+	if (ret) {
+		dev_err(dev, "failed to request irq %d\n", pp->irq);
+		return ret;
+	}
+
+	pp->root_bus_nr = -1;
+	pp->ops = &spear13xx_pcie_host_ops;
+
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(dev, "failed to initialize host\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __init spear13xx_pcie_probe(struct platform_device *pdev)
+{
+	struct spear13xx_pcie *spear13xx_pcie;
+	struct pcie_port *pp;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *dbi_base;
+	int ret;
+
+	spear13xx_pcie = devm_kzalloc(dev, sizeof(*spear13xx_pcie), GFP_KERNEL);
+	if (!spear13xx_pcie) {
+		dev_err(dev, "no memory for SPEAr13xx pcie\n");
+		return -ENOMEM;
+	}
+
+	spear13xx_pcie->phy = devm_phy_get(dev, "pcie-phy");
+	if (IS_ERR(spear13xx_pcie->phy)) {
+		ret = PTR_ERR(spear13xx_pcie->phy);
+		if (ret == -EPROBE_DEFER)
+			dev_info(dev, "probe deferred\n");
+		else
+			dev_err(dev, "couldn't get pcie-phy\n");
+		return ret;
+	}
+
+	phy_init(spear13xx_pcie->phy);
+
+	spear13xx_pcie->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(spear13xx_pcie->clk)) {
+		dev_err(dev, "couldn't get clk for pcie\n");
+		return PTR_ERR(spear13xx_pcie->clk);
+	}
+	ret = clk_prepare_enable(spear13xx_pcie->clk);
+	if (ret) {
+		dev_err(dev, "couldn't enable clk for pcie\n");
+		return ret;
+	}
+
+	pp = &spear13xx_pcie->pp;
+
+	pp->dev = dev;
+
+	dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pp->dbi_base = devm_ioremap_resource(dev, dbi_base);
+	if (IS_ERR(pp->dbi_base)) {
+		dev_err(dev, "couldn't remap dbi base %p\n", dbi_base);
+		ret = PTR_ERR(pp->dbi_base);
+		goto fail_clk;
+	}
+	spear13xx_pcie->app_base = pp->dbi_base + 0x2000;
+
+	if (of_property_read_bool(np, "st,pcie-is-gen1"))
+		spear13xx_pcie->is_gen1 = true;
+
+	ret = add_pcie_port(pp, pdev);
+	if (ret < 0)
+		goto fail_clk;
+
+	platform_set_drvdata(pdev, spear13xx_pcie);
+	return 0;
+
+fail_clk:
+	clk_disable_unprepare(spear13xx_pcie->clk);
+
+	return ret;
+}
+
+static int __exit spear13xx_pcie_remove(struct platform_device *pdev)
+{
+	struct spear13xx_pcie *spear13xx_pcie = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(spear13xx_pcie->clk);
+
+	phy_exit(spear13xx_pcie->phy);
+
+	return 0;
+}
+
+static const struct of_device_id spear13xx_pcie_of_match[] = {
+	{ .compatible = "st,spear1340-pcie", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, spear13xx_pcie_of_match);
+
+static struct platform_driver spear13xx_pcie_driver = {
+	.probe		= spear13xx_pcie_probe,
+	.remove		= spear13xx_pcie_remove,
+	.driver = {
+		.name	= "spear-pcie",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(spear13xx_pcie_of_match),
+	},
+};
+
+/* SPEAr13xx PCIe driver does not allow module unload */
+
+static int __init pcie_init(void)
+{
+	return platform_driver_register(&spear13xx_pcie_driver);
+}
+module_init(pcie_init);
+
+MODULE_DESCRIPTION("ST Microelectronics SPEAr13xx PCIe host controller driver");
+MODULE_AUTHOR("Pratyush Anand <pratyush.anand@st.com>");
+MODULE_LICENSE("GPL v2");