[PATCH v1 4/5] pci: dw: add common functions to support old hw based pci driver

[Murali Karicheri]

The older version of DW hw has application space registers for MSI
controller and inbound/outbound access configuration. Also the legacy
interrupt has registers in the application space. Drivers such as
keystone pci uses these common functions to implement the driver.
These are re-factored from the original driver to separate files
to allow re-use for the next driver that is based on old dw pci hw such
as that found on keystone.

CC: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
CC: Mohit Kumar <mohit.kumar@xxxxxx>
CC: Jingoo Han <jg1.han@xxxxxxxxxxx>
CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
---
 drivers/pci/host/Kconfig          |    6 +-
 drivers/pci/host/Makefile         |    1 +
 drivers/pci/host/pci-dw-old-msi.c |  150 +++++++++++++++
 drivers/pci/host/pci-dw-old.c     |  371 +++++++++++++++++++++++++++++++++++++
 drivers/pci/host/pci-dw-old.h     |   30 +++
 5 files changed, 557 insertions(+), 1 deletion(-)
 create mode 100644 drivers/pci/host/pci-dw-old-msi.c
 create mode 100644 drivers/pci/host/pci-dw-old.c
 create mode 100644 drivers/pci/host/pci-dw-old.h

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index a6f67ec..c4f4732 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -9,6 +9,11 @@ config PCI_MVEBU
 config PCIE_DW
 	bool
 
+config PCI_DW_OLD
+	bool "Designware Old PCIe h/w"
+	help
+	   Say Y here if the DW h/w is old version (3.65)
+
 config PCI_EXYNOS
 	bool "Samsung Exynos PCIe controller"
 	depends on SOC_EXYNOS5440
@@ -32,5 +37,4 @@ config PCI_RCAR_GEN2
 	  Say Y here if you want internal PCI support on R-Car Gen2 SoC.
 	  There are 3 internal PCI controllers available with a single
 	  built-in EHCI/OHCI host controller present on each one.
-
 endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 13fb333..be5d939 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
 obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
+obj-$(CONFIG_PCI_DW_OLD) += pci-dw-old-msi.o pci-dw-old.o
diff --git a/drivers/pci/host/pci-dw-old-msi.c b/drivers/pci/host/pci-dw-old-msi.c
new file mode 100644
index 0000000..450bb2f
--- /dev/null
+++ b/drivers/pci/host/pci-dw-old-msi.c
@@ -0,0 +1,150 @@
+/*
+ * Designware(dw) old MSI controller (v3.65 or similar)
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@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/of_irq.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/pci.h>
+
+#include "pcie-designware.h"
+#include "pci-dw-old.h"
+
+#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 IRQ_EOI                         0x050
+#define MSI_IRQ_OFFSET			4
+
+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;
+}
+
+inline u32 dw_old_get_msi_data(struct pcie_port *pp)
+{
+	return pp->app_base + MSI_IRQ;
+}
+
+void dw_old_handle_msi_irq(struct pcie_port *pp, int offset)
+{
+	u32 pending, vector;
+	int src, virq;
+
+	pending = readl(pp->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 dw_old_msi_irq_ack(struct irq_data *d)
+{
+	u32 offset, reg_offset, bit_pos;
+	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);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);
+
+	writel(BIT(bit_pos),
+		pp->va_app_base + MSI0_IRQ_STATUS + (reg_offset << 4));
+	writel(reg_offset + MSI_IRQ_OFFSET, pp->va_app_base + IRQ_EOI);
+}
+
+static void dw_old_msi_irq_mask(struct irq_data *d)
+{
+	u32 offset, reg_offset, bit_pos;
+	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);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);
+
+	/* mask the end point if PVM implemented */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		if (msi->msi_attrib.maskbit)
+			mask_msi_irq(d);
+	}
+
+	writel(BIT(bit_pos),
+		pp->va_app_base + MSI0_IRQ_ENABLE_CLR + (reg_offset << 4));
+}
+
+static void dw_old_msi_irq_unmask(struct irq_data *d)
+{
+	u32 offset, reg_offset, bit_pos;
+	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);
+	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
+	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);
+
+	/* mask the end point if PVM implemented */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		if (msi->msi_attrib.maskbit)
+			unmask_msi_irq(d);
+	}
+
+	writel(BIT(bit_pos),
+		pp->va_app_base + MSI0_IRQ_ENABLE_SET + (reg_offset << 4));
+}
+
+static struct irq_chip dw_old_msi_chip = {
+	.name = "PCI-DW-MSI-OLD",
+	.irq_ack = dw_old_msi_irq_ack,
+	.irq_mask = dw_old_msi_irq_mask,
+	.irq_unmask = dw_old_msi_irq_unmask,
+};
+
+static int dw_old_msi_map(struct irq_domain *domain, unsigned int irq,
+			irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &dw_old_msi_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 dw_old_msi_domain_ops = {
+	.map = dw_old_msi_map,
+};
diff --git a/drivers/pci/host/pci-dw-old.c b/drivers/pci/host/pci-dw-old.c
new file mode 100644
index 0000000..b805013
--- /dev/null
+++ b/drivers/pci/host/pci-dw-old.c
@@ -0,0 +1,371 @@
+/*
+ * Designware(dw) old common functions (v3.65 or similar)
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@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/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+
+#include "pcie-designware.h"
+#include "pci-dw-old.h"
+
+/* Application register defines */
+#define LTSSM_EN_VAL		        BIT(0)
+#define LTSSM_STATE_MASK	        0x1f
+#define LTSSM_STATE_L0		        0x11
+#define DIR_SPD				(1 << 17)
+#define DBI_CS2_EN_VAL		        BIT(5)
+#define OB_XLAT_EN_VAL		        BIT(1)
+
+/* 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))
+#define IRQ_EOI                         0x050
+#define IRQ_STATUS			0x184
+#define IRQ_ENABLE_SET			0x188
+#define IRQ_ENABLE_CLR			0x18c
+
+/* Config space registers */
+#define DEBUG0			        0x728
+#define PL_GEN2			        0x80c
+
+static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
+{
+	return sys->private_data;
+}
+
+void dw_old_enable_legacy_irqs(struct pcie_port *pp)
+{
+	int i;
+
+	for (i = 0; i < MAX_LEGACY_IRQS; i++)
+		writel(0x1, pp->va_app_base + IRQ_ENABLE_SET + (i << 4));
+}
+
+void dw_old_handle_legacy_irq(struct pcie_port *pp, int offset)
+{
+	u32 pending;
+	int virq;
+
+	pending = readl(pp->va_app_base + IRQ_STATUS + (offset << 4));
+
+	if (BIT(0) & pending) {
+		virq = irq_linear_revmap(pp->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, pp->va_app_base + IRQ_EOI);
+}
+
+static void dw_old_ack_irq(struct irq_data *d)
+{
+}
+
+static void dw_old_mask_irq(struct irq_data *d)
+{
+}
+
+static void dw_old_unmask_irq(struct irq_data *d)
+{
+}
+
+struct irq_chip dw_old_legacy_irq_chip = {
+	.name = "PCI-DW-LEGACY-old-irq",
+	.irq_ack = dw_old_ack_irq,
+	.irq_mask = dw_old_mask_irq,
+	.irq_unmask = dw_old_unmask_irq,
+};
+
+static int dw_old_init_legacy_irq_map(struct irq_domain *d, unsigned int irq,
+				      irq_hw_number_t hw)
+{
+	irq_set_chip_and_handler(irq, &dw_old_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 dw_old_legacy_irq_domian_ops = {
+	.map = dw_old_init_legacy_irq_map,
+	.xlate = irq_domain_xlate_onetwocell,
+};
+
+/**
+ * dw_old_set_outbound_trans() - Set PHYADDR <-> BUSADDR
+ * mapping for outbound
+ */
+void dw_old_setup_ob_regs(struct pcie_port *pp)
+{
+	u32 start = pp->mem.start, end = pp->mem.end;
+	int i, tr_size;
+
+	dev_dbg(pp->dev, "Setting outbound translation for %#x-%#x\n",
+		start, end);
+
+	/* Set outbound translation size per window division */
+	writel(CFG_PCIM_WIN_SZ_IDX & 0x7, pp->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, pp->va_app_base + OB_OFFSET_INDEX(i));
+		writel(0, pp->va_app_base + OB_OFFSET_HI(i));
+		start += tr_size;
+	}
+
+	/* Enable OB translation */
+	writel(OB_XLAT_EN_VAL | readl(pp->va_app_base + CMD_STATUS),
+		pp->va_app_base + CMD_STATUS);
+}
+
+/**
+ * dw_old_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 inline void dw_old_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));
+}
+
+/**
+ * dw_old_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 inline void dw_old_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 dw_old_disable_bars(struct pcie_port *pp)
+{
+	dw_old_set_dbi_mode(pp->va_app_base);
+	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_0);
+	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_1);
+	dw_old_clear_dbi_mode(pp->va_app_base);
+}
+
+/**
+ * dw_old_setup_config_addr() - Set up configuration space address for a
+ * device
+ *
+ * @pp: ptr to pcie_port structure
+ * @bus: Bus number the device is residing on
+ * @device: Device number
+ * @function: Function number in device
+ *
+ * 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 inline void __iomem *
+dw_old_setup_config_addr(struct pcie_port *pp, u8 bus, u8 device, u8 function)
+{
+	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, pp->va_app_base + CFG_SETUP);
+
+	return pp->dbi_base + SPACE0_REMOTE_CFG_OFFSET;
+}
+
+int dw_old_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+		unsigned int devfn, int where, int size, u32 *val)
+{
+	u8 bus_num = bus->number;
+	void __iomem *addr;
+	int ret;
+
+	addr = dw_old_setup_config_addr(pp, bus_num, PCI_SLOT(devfn),
+				 PCI_FUNC(devfn));
+
+	ret = dw_pcie_cfg_read(addr + (where & ~0x3), where, size, val);
+
+	return ret;
+}
+
+int dw_old_wr_other_conf(struct pcie_port *pp,
+		struct pci_bus *bus, unsigned int devfn, int where,
+		int size, u32 val)
+{
+	u8 bus_num = bus->number;
+	void __iomem *addr;
+
+	addr = dw_old_setup_config_addr(pp, bus_num, PCI_SLOT(devfn),
+				PCI_FUNC(devfn));
+	return dw_pcie_cfg_write(addr + (where & ~0x3), where, size, val);
+}
+
+/**
+ * dw_old_set_ib_access() - Setup inbound access
+ *
+ * Configure BAR0 for inbound access. BAR0 is set up in h/w to have
+ * access to PCIESS application register space and just needs to set up
+ * inbound address (mainly used for MSI).
+ */
+static void dw_old_set_ib_access(struct pcie_port *pp)
+{
+	/* Configure and set up BAR0 */
+	dw_old_set_dbi_mode(pp->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);
+
+	dw_old_clear_dbi_mode(pp->va_app_base);
+	 /*
+	  * For BAR0, just setting bus address for inbound writes (MSI) should
+	  * be sufficient. Use physical address to avoid any conflicts.
+	  */
+	writel(pp->app_base, pp->dbi_base + PCI_BASE_ADDRESS_0);
+}
+
+/**
+ * dw_old_pcie_scan_bus() - common function to scan bus
+ *
+ * common functin to scan old dw based pci bus. This also sets inbound access
+ * after scan.
+ */
+static struct pci_bus *dw_old_pcie_scan_bus(int nr, struct pci_sys_data *sys)
+{
+	struct pcie_port *pp = sys_to_pcie(sys);
+	struct pci_bus *bus;
+
+	bus = dw_pcie_scan_bus(nr, sys);
+	if (bus)
+		dw_old_set_ib_access(pp);
+
+	return bus;
+}
+
+/**
+ * dw_old_pcie_link_up() - Check if link up
+ *
+ * optionally enable link train using link_train option and check if link is up.
+ */
+int dw_old_pcie_link_up(struct pcie_port *pp, int link_train)
+{
+	u32 val;
+
+	if (link_train) {
+		/*
+		 * KeyStone devices do not support h/w autonomous
+		 * link up-training to GEN2 from GEN1 in either EP/RC modes.
+		 * The software needs to initiate speed change.
+		 */
+		val = readl(pp->dbi_base + PL_GEN2);
+		writel(val | DIR_SPD, pp->dbi_base + PL_GEN2);
+		/*
+		 * Initiate Link Training. We will delay for L0 as specified by
+		 * standard, but will still proceed and return success
+		 * irrespective of L0 status as this will be handled by explicit
+		 * L0 state checks during enumeration.
+		 */
+		val = readl(pp->va_app_base + CMD_STATUS);
+		writel(LTSSM_EN_VAL | val,  pp->va_app_base + CMD_STATUS);
+
+	}
+
+	val = readl(pp->dbi_base + DEBUG0);
+
+	return (val & LTSSM_STATE_MASK) == LTSSM_STATE_L0;
+}
+
+static struct hw_pci dw_old_pcie_hw = {
+	.nr_controllers	= 1,
+	.setup		= dw_pcie_setup,
+	.scan		= dw_old_pcie_scan_bus,
+	.swizzle        = pci_common_swizzle,
+	.add_bus	= dw_pcie_add_bus,
+	.map_irq	= of_irq_parse_and_map_pci,
+};
+
+
+/**
+ * dw_old_pcie_host_init() - initialize host for old dw hardware
+ *
+ * Parse the pcie resources from DT bindings and then call common
+ * dw function to do host initialization.
+ */
+int __init dw_old_pcie_host_init(struct pcie_port *pp, struct device_node *np)
+{
+	int ret;
+
+	if (!pp->va_app_base)
+		return -EINVAL;
+
+	/* create legacy domain */
+	pp->legacy_irq_domain = irq_domain_add_linear(np,
+				MAX_LEGACY_IRQS,
+				&dw_old_legacy_irq_domian_ops, NULL);
+
+	if (!pp->legacy_irq_domain) {
+		dev_err(pp->dev, "Failed to add irq domain for legacy irqs\n");
+		return -EINVAL;
+	}
+
+	ret = dw_pcie_parse_resource(pp);
+	if (ret)
+		return ret;
+
+	return dw_pcie_common_host_init(pp, &dw_old_pcie_hw,
+					&dw_old_msi_domain_ops);
+}
diff --git a/drivers/pci/host/pci-dw-old.h b/drivers/pci/host/pci-dw-old.h
new file mode 100644
index 0000000..6e1af50
--- /dev/null
+++ b/drivers/pci/host/pci-dw-old.h
@@ -0,0 +1,30 @@
+/*
+ * Designware(dw) old MSI controller (v3.65 or similar) common includes
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@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.
+ */
+
+#define MAX_LEGACY_IRQS		4
+
+extern const struct irq_domain_ops dw_old_msi_domain_ops;
+
+void dw_old_handle_msi_irq(struct pcie_port *pp, int offset);
+u32 dw_old_get_msi_data(struct pcie_port *pp);
+void dw_old_enable_legacy_irqs(struct pcie_port *pp);
+void dw_old_handle_legacy_irq(struct pcie_port *pp, int offset);
+int  dw_old_pcie_host_init(struct pcie_port *pp, struct device_node *np);
+int dw_old_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+		unsigned int devfn, int where, int size, u32 val);
+int dw_old_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+		unsigned int devfn, int where, int size, u32 *val);
+void dw_old_disable_bars(struct pcie_port *pp);
+void dw_old_setup_ob_regs(struct pcie_port *pp);
+int dw_old_pcie_link_up(struct pcie_port *pp, int link_train);
-- 
1.7.9.5

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