PCI: keystone: Add TI Keystone PCIe driver

The Keystone PCIe controller is based on v3.65 version of the Designware
h/w.  Main differences are:

    1. No ATU support
    2. Legacy and MSI IRQ functions are implemented in application register
       space
    3. MSI interrupts are multiplexed over 8 IRQ lines to the Host side.

All of the application register space handing code is organized into
pci-keystone-dw.c and the functions are called from pci-keystone.c to
implement PCI controller driver.  Also add necessary DT documentation and
update the MAINTAINERS file for the driver.

[bhelgaas: spelling and whitespace fixes]
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mohit Kumar <mohit.kumar@st.com>
CC: Pratyush Anand <pratyush.anand@st.com>
CC: Jingoo Han <jg1.han@samsung.com>
CC: Richard Zhu <r65037@freescale.com>
CC: Kishon Vijay Abraham I <kishon@ti.com>
CC: Marek Vasut <marex@denx.de>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Grant Likely <grant.likely@linaro.org>

1 files changed, 516 insertions, 0 deletions

diff --git a/drivers/pci/host/pci-keystone-dw.c b/drivers/pci/host/pci-keystone-dw.c
new file mode 100644
index 000000000000..2434786ca40b
--- /dev/null
+++ b/drivers/pci/host/pci-keystone-dw.c
@@ -0,0 +1,516 @@
+/*
+ * Designware application register space functions for Keystone PCI controller
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@ti.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/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+
+#include "pcie-designware.h"
+#include "pci-keystone.h"
+
+/* Application register defines */
+#define LTSSM_EN_VAL		        1
+#define LTSSM_STATE_MASK		0x1f
+#define LTSSM_STATE_L0			0x11
+#define DBI_CS2_EN_VAL			0x20
+#define OB_XLAT_EN_VAL		        2
+
+/* Application registers */
+#define CMD_STATUS			0x004
+#define CFG_SETUP			0x008
+#define OB_SIZE				0x030
+#define CFG_PCIM_WIN_SZ_IDX		3
+#define CFG_PCIM_WIN_CNT		32
+#define SPACE0_REMOTE_CFG_OFFSET	0x1000
+#define OB_OFFSET_INDEX(n)		(0x200 + (8 * n))
+#define OB_OFFSET_HI(n)			(0x204 + (8 * n))
+
+/* IRQ register defines */
+#define IRQ_EOI				0x050
+#define IRQ_STATUS			0x184
+#define IRQ_ENABLE_SET			0x188
+#define IRQ_ENABLE_CLR			0x18c
+
+#define MSI_IRQ				0x054
+#define MSI0_IRQ_STATUS			0x104
+#define MSI0_IRQ_ENABLE_SET		0x108
+#define MSI0_IRQ_ENABLE_CLR		0x10c
+#define IRQ_STATUS			0x184
+#define MSI_IRQ_OFFSET			4
+
+/* Config space registers */
+#define DEBUG0				0x728
+
+#define to_keystone_pcie(x)	container_of(x, struct keystone_pcie, pp)
+
+static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
+{
+	return sys->private_data;
+}
+
+static inline void update_reg_offset_bit_pos(u32 offset, u32 *reg_offset,
+					     u32 *bit_pos)
+{
+	*reg_offset = offset % 8;
+	*bit_pos = offset >> 3;
+}
+
+u32 ks_dw_pcie_get_msi_data(struct pcie_port *pp)
+{
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+
+	return ks_pcie->app.start + MSI_IRQ;
+}
+
+void ks_dw_pcie_handle_msi_irq(struct keystone_pcie *ks_pcie, int offset)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	u32 pending, vector;
+	int src, virq;
+
+	pending = readl(ks_pcie->va_app_base + MSI0_IRQ_STATUS + (offset << 4));
+
+	/*
+	 * MSI0 status bit 0-3 shows vectors 0, 8, 16, 24, MSI1 status bit
+	 * shows 1, 9, 17, 25 and so forth
+	 */
+	for (src = 0; src < 4; src++) {
+		if (BIT(src) & pending) {
+			vector = offset + (src << 3);
+			virq = irq_linear_revmap(pp->irq_domain, vector);
+			dev_dbg(pp->dev, "irq: bit %d, vector %d, virq %d\n",
+				src, vector, virq);
+			generic_handle_irq(virq);
+		}
+	}
+}
+
+static void ks_dw_pcie_msi_irq_ack(struct irq_data *d)
+{
+	u32 offset, reg_offset, bit_pos;
+	struct keystone_pcie *ks_pcie;
+	unsigned int irq = d->irq;
+	struct msi_desc *msi;
+	struct pcie_port *pp;
+
+	msi = irq_get_msi_desc(irq);
+	pp = sys_to_pcie(msi->dev->bus->sysdata);
+	ks_pcie = to_keystone_pcie(pp);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);
+
+	writel(BIT(bit_pos),
+	       ks_pcie->va_app_base + MSI0_IRQ_STATUS + (reg_offset << 4));
+	writel(reg_offset + MSI_IRQ_OFFSET, ks_pcie->va_app_base + IRQ_EOI);
+}
+
+void ks_dw_pcie_msi_set_irq(struct pcie_port *pp, int irq)
+{
+	u32 reg_offset, bit_pos;
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+
+	update_reg_offset_bit_pos(irq, &reg_offset, &bit_pos);
+	writel(BIT(bit_pos),
+	       ks_pcie->va_app_base + MSI0_IRQ_ENABLE_SET + (reg_offset << 4));
+}
+
+void ks_dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq)
+{
+	u32 reg_offset, bit_pos;
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+
+	update_reg_offset_bit_pos(irq, &reg_offset, &bit_pos);
+	writel(BIT(bit_pos),
+	       ks_pcie->va_app_base + MSI0_IRQ_ENABLE_CLR + (reg_offset << 4));
+}
+
+static void ks_dw_pcie_msi_irq_mask(struct irq_data *d)
+{
+	struct keystone_pcie *ks_pcie;
+	unsigned int irq = d->irq;
+	struct msi_desc *msi;
+	struct pcie_port *pp;
+	u32 offset;
+
+	msi = irq_get_msi_desc(irq);
+	pp = sys_to_pcie(msi->dev->bus->sysdata);
+	ks_pcie = to_keystone_pcie(pp);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+
+	/* Mask the end point if PVM implemented */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		if (msi->msi_attrib.maskbit)
+			mask_msi_irq(d);
+	}
+
+	ks_dw_pcie_msi_clear_irq(pp, offset);
+}
+
+static void ks_dw_pcie_msi_irq_unmask(struct irq_data *d)
+{
+	struct keystone_pcie *ks_pcie;
+	unsigned int irq = d->irq;
+	struct msi_desc *msi;
+	struct pcie_port *pp;
+	u32 offset;
+
+	msi = irq_get_msi_desc(irq);
+	pp = sys_to_pcie(msi->dev->bus->sysdata);
+	ks_pcie = to_keystone_pcie(pp);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+
+	/* Mask the end point if PVM implemented */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		if (msi->msi_attrib.maskbit)
+			unmask_msi_irq(d);
+	}
+
+	ks_dw_pcie_msi_set_irq(pp, offset);
+}
+
+static struct irq_chip ks_dw_pcie_msi_irq_chip = {
+	.name = "Keystone-PCIe-MSI-IRQ",
+	.irq_ack = ks_dw_pcie_msi_irq_ack,
+	.irq_mask = ks_dw_pcie_msi_irq_mask,
+	.irq_unmask = ks_dw_pcie_msi_irq_unmask,
+};
+
+static int ks_dw_pcie_msi_map(struct irq_domain *domain, unsigned int irq,
+			      irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &ks_dw_pcie_msi_irq_chip,
+				 handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	set_irq_flags(irq, IRQF_VALID);
+
+	return 0;
+}
+
+const struct irq_domain_ops ks_dw_pcie_msi_domain_ops = {
+	.map = ks_dw_pcie_msi_map,
+};
+
+int ks_dw_pcie_msi_host_init(struct pcie_port *pp, struct msi_chip *chip)
+{
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+	int i;
+
+	pp->irq_domain = irq_domain_add_linear(ks_pcie->msi_intc_np,
+					MAX_MSI_IRQS,
+					&ks_dw_pcie_msi_domain_ops,
+					chip);
+	if (!pp->irq_domain) {
+		dev_err(pp->dev, "irq domain init failed\n");
+		return -ENXIO;
+	}
+
+	for (i = 0; i < MAX_MSI_IRQS; i++)
+		irq_create_mapping(pp->irq_domain, i);
+
+	return 0;
+}
+
+void ks_dw_pcie_enable_legacy_irqs(struct keystone_pcie *ks_pcie)
+{
+	int i;
+
+	for (i = 0; i < MAX_LEGACY_IRQS; i++)
+		writel(0x1, ks_pcie->va_app_base + IRQ_ENABLE_SET + (i << 4));
+}
+
+void ks_dw_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, int offset)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	u32 pending;
+	int virq;
+
+	pending = readl(ks_pcie->va_app_base + IRQ_STATUS + (offset << 4));
+
+	if (BIT(0) & pending) {
+		virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, offset);
+		dev_dbg(pp->dev, ": irq: irq_offset %d, virq %d\n", offset,
+			virq);
+		generic_handle_irq(virq);
+	}
+
+	/* EOI the INTx interrupt */
+	writel(offset, ks_pcie->va_app_base + IRQ_EOI);
+}
+
+static void ks_dw_pcie_ack_legacy_irq(struct irq_data *d)
+{
+}
+
+static void ks_dw_pcie_mask_legacy_irq(struct irq_data *d)
+{
+}
+
+static void ks_dw_pcie_unmask_legacy_irq(struct irq_data *d)
+{
+}
+
+static struct irq_chip ks_dw_pcie_legacy_irq_chip = {
+	.name = "Keystone-PCI-Legacy-IRQ",
+	.irq_ack = ks_dw_pcie_ack_legacy_irq,
+	.irq_mask = ks_dw_pcie_mask_legacy_irq,
+	.irq_unmask = ks_dw_pcie_unmask_legacy_irq,
+};
+
+static int ks_dw_pcie_init_legacy_irq_map(struct irq_domain *d,
+				unsigned int irq, irq_hw_number_t hw_irq)
+{
+	irq_set_chip_and_handler(irq, &ks_dw_pcie_legacy_irq_chip,
+				 handle_level_irq);
+	irq_set_chip_data(irq, d->host_data);
+	set_irq_flags(irq, IRQF_VALID);
+
+	return 0;
+}
+
+static const struct irq_domain_ops ks_dw_pcie_legacy_irq_domain_ops = {
+	.map = ks_dw_pcie_init_legacy_irq_map,
+	.xlate = irq_domain_xlate_onetwocell,
+};
+
+/**
+ * ks_dw_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask
+ * registers
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_dw_pcie_set_dbi_mode(void __iomem *reg_virt)
+{
+	u32 val;
+
+	writel(DBI_CS2_EN_VAL | readl(reg_virt + CMD_STATUS),
+	       reg_virt + CMD_STATUS);
+
+	do {
+		val = readl(reg_virt + CMD_STATUS);
+	} while (!(val & DBI_CS2_EN_VAL));
+}
+
+/**
+ * ks_dw_pcie_clear_dbi_mode() - Disable DBI mode
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_dw_pcie_clear_dbi_mode(void __iomem *reg_virt)
+{
+	u32 val;
+
+	writel(~DBI_CS2_EN_VAL & readl(reg_virt + CMD_STATUS),
+		     reg_virt + CMD_STATUS);
+
+	do {
+		val = readl(reg_virt + CMD_STATUS);
+	} while (val & DBI_CS2_EN_VAL);
+}
+
+void ks_dw_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	u32 start = pp->mem.start, end = pp->mem.end;
+	int i, tr_size;
+
+	/* Disable BARs for inbound access */
+	ks_dw_pcie_set_dbi_mode(ks_pcie->va_app_base);
+	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_0);
+	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_1);
+	ks_dw_pcie_clear_dbi_mode(ks_pcie->va_app_base);
+
+	/* Set outbound translation size per window division */
+	writel(CFG_PCIM_WIN_SZ_IDX & 0x7, ks_pcie->va_app_base + OB_SIZE);
+
+	tr_size = (1 << (CFG_PCIM_WIN_SZ_IDX & 0x7)) * SZ_1M;
+
+	/* Using Direct 1:1 mapping of RC <-> PCI memory space */
+	for (i = 0; (i < CFG_PCIM_WIN_CNT) && (start < end); i++) {
+		writel(start | 1, ks_pcie->va_app_base + OB_OFFSET_INDEX(i));
+		writel(0, ks_pcie->va_app_base + OB_OFFSET_HI(i));
+		start += tr_size;
+	}
+
+	/* Enable OB translation */
+	writel(OB_XLAT_EN_VAL | readl(ks_pcie->va_app_base + CMD_STATUS),
+	       ks_pcie->va_app_base + CMD_STATUS);
+}
+
+/**
+ * ks_pcie_cfg_setup() - Set up configuration space address for a device
+ *
+ * @ks_pcie: ptr to keystone_pcie structure
+ * @bus: Bus number the device is residing on
+ * @devfn: device, function number info
+ *
+ * Forms and returns the address of configuration space mapped in PCIESS
+ * address space 0.  Also configures CFG_SETUP for remote configuration space
+ * access.
+ *
+ * The address space has two regions to access configuration - local and remote.
+ * We access local region for bus 0 (as RC is attached on bus 0) and remote
+ * region for others with TYPE 1 access when bus > 1.  As for device on bus = 1,
+ * we will do TYPE 0 access as it will be on our secondary bus (logical).
+ * CFG_SETUP is needed only for remote configuration access.
+ */
+static void __iomem *ks_pcie_cfg_setup(struct keystone_pcie *ks_pcie, u8 bus,
+				       unsigned int devfn)
+{
+	u8 device = PCI_SLOT(devfn), function = PCI_FUNC(devfn);
+	struct pcie_port *pp = &ks_pcie->pp;
+	u32 regval;
+
+	if (bus == 0)
+		return pp->dbi_base;
+
+	regval = (bus << 16) | (device << 8) | function;
+
+	/*
+	 * Since Bus#1 will be a virtual bus, we need to have TYPE0
+	 * access only.
+	 * TYPE 1
+	 */
+	if (bus != 1)
+		regval |= BIT(24);
+
+	writel(regval, ks_pcie->va_app_base + CFG_SETUP);
+	return pp->va_cfg0_base;
+}
+
+int ks_dw_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+			     unsigned int devfn, int where, int size, u32 *val)
+{
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+	u8 bus_num = bus->number;
+	void __iomem *addr;
+
+	addr = ks_pcie_cfg_setup(ks_pcie, bus_num, devfn);
+
+	return dw_pcie_cfg_read(addr + (where & ~0x3), where, size, val);
+}
+
+int ks_dw_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+			     unsigned int devfn, int where, int size, u32 val)
+{
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+	u8 bus_num = bus->number;
+	void __iomem *addr;
+
+	addr = ks_pcie_cfg_setup(ks_pcie, bus_num, devfn);
+
+	return dw_pcie_cfg_write(addr + (where & ~0x3), where, size, val);
+}
+
+/**
+ * ks_dw_pcie_v3_65_scan_bus() - keystone scan_bus post initialization
+ *
+ * This sets BAR0 to enable inbound access for MSI_IRQ register
+ */
+void ks_dw_pcie_v3_65_scan_bus(struct pcie_port *pp)
+{
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+
+	/* Configure and set up BAR0 */
+	ks_dw_pcie_set_dbi_mode(ks_pcie->va_app_base);
+
+	/* Enable BAR0 */
+	writel(1, pp->dbi_base + PCI_BASE_ADDRESS_0);
+	writel(SZ_4K - 1, pp->dbi_base + PCI_BASE_ADDRESS_0);
+
+	ks_dw_pcie_clear_dbi_mode(ks_pcie->va_app_base);
+
+	 /*
+	  * For BAR0, just setting bus address for inbound writes (MSI) should
+	  * be sufficient.  Use physical address to avoid any conflicts.
+	  */
+	writel(ks_pcie->app.start, pp->dbi_base + PCI_BASE_ADDRESS_0);
+}
+
+/**
+ * ks_dw_pcie_link_up() - Check if link up
+ */
+int ks_dw_pcie_link_up(struct pcie_port *pp)
+{
+	u32 val = readl(pp->dbi_base + DEBUG0);
+
+	return (val & LTSSM_STATE_MASK) == LTSSM_STATE_L0;
+}
+
+void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie)
+{
+	u32 val;
+
+	/* Disable Link training */
+	val = readl(ks_pcie->va_app_base + CMD_STATUS);
+	val &= ~LTSSM_EN_VAL;
+	writel(LTSSM_EN_VAL | val,  ks_pcie->va_app_base + CMD_STATUS);
+
+	/* Initiate Link Training */
+	val = readl(ks_pcie->va_app_base + CMD_STATUS);
+	writel(LTSSM_EN_VAL | val,  ks_pcie->va_app_base + CMD_STATUS);
+}
+
+/**
+ * ks_dw_pcie_host_init() - initialize host for v3_65 dw hardware
+ *
+ * Ioremap the register resources, initialize legacy irq domain
+ * and call dw_pcie_v3_65_host_init() API to initialize the Keystone
+ * PCI host controller.
+ */
+int __init ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
+				struct device_node *msi_intc_np)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	struct platform_device *pdev = to_platform_device(pp->dev);
+	struct resource *res;
+
+	/* Index 0 is the config reg. space address */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pp->dbi_base = devm_ioremap_resource(pp->dev, res);
+	if (IS_ERR(pp->dbi_base))
+		return PTR_ERR(pp->dbi_base);
+
+	/*
+	 * We set these same and is used in pcie rd/wr_other_conf
+	 * functions
+	 */
+	pp->va_cfg0_base = pp->dbi_base + SPACE0_REMOTE_CFG_OFFSET;
+	pp->va_cfg1_base = pp->va_cfg0_base;
+
+	/* Index 1 is the application reg. space address */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	ks_pcie->app = *res;
+	ks_pcie->va_app_base = devm_ioremap_resource(pp->dev, res);
+	if (IS_ERR(ks_pcie->va_app_base))
+		return PTR_ERR(ks_pcie->va_app_base);
+
+	/* Create legacy IRQ domain */
+	ks_pcie->legacy_irq_domain =
+			irq_domain_add_linear(ks_pcie->legacy_intc_np,
+					MAX_LEGACY_IRQS,
+					&ks_dw_pcie_legacy_irq_domain_ops,
+					NULL);
+	if (!ks_pcie->legacy_irq_domain) {
+		dev_err(pp->dev, "Failed to add irq domain for legacy irqs\n");
+		return -EINVAL;
+	}
+
+	return dw_pcie_host_init(pp);
+}