[PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Subrahmanya Lingappa]

Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP -
GPEX 4.0, a PCIe gen4 IP. This IP has upto 8
outbound and inbound windows for the address translation.

Signed-off-by: Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>
Cc: Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
Cc: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>
Cc: linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 drivers/pci/host/Kconfig         |   8 +
 drivers/pci/host/Makefile        |   1 +
 drivers/pci/host/pcie-mobiveil.c | 653 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 662 insertions(+)
 create mode 100644 drivers/pci/host/pcie-mobiveil.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 38d1298..09bf1d9 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -27,6 +27,14 @@ config PCIE_XILINX_NWL
 	 or End Point. The current option selection will only
 	 support root port enabling.
 
+config PCIE_MOBIVEIL
+        bool "Mobiveil AXI PCIe host bridge support"
+        depends on ARCH_ZYNQMP || COMPILE_TEST
+        depends on PCI_MSI_IRQ_DOMAIN
+        help
+          Say 'Y' here if you want kernel to support the Mobiveil AXI PCIe
+          Host Bridge driver.
+
 config PCI_FTPCI100
 	bool "Faraday Technology FTPCI100 PCI controller"
 	depends on OF
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 34ec1d8..d745d68 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_PCIE_ROCKCHIP) += pcie-rockchip.o
 obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o
 obj-$(CONFIG_PCIE_TANGO_SMP8759) += pcie-tango.o
 obj-$(CONFIG_VMD) += vmd.o
+obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
 
 # The following drivers are for devices that use the generic ACPI
 # pci_root.c driver but don't support standard ECAM config access.
diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
new file mode 100644
index 0000000..8611aaa
--- /dev/null
+++ b/drivers/pci/host/pcie-mobiveil.c
@@ -0,0 +1,653 @@
+/*
+ * PCIe host controller driver for Mobiveil PCIe Host controller
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2017 Mobiveil Inc.
+ * Author: Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* register offsets and bit positions */
+
+/*
+ * translation tables are grouped into windows, each window registers are
+ * grouped into blocks of 4 or 16 registers each
+ */
+#define PAB_REG_BLOCK_SIZE_4	4
+#define PAB_REG_BLOCK_SIZE_16	16
+#define PAB_REG_ADDR_4(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_4))
+#define PAB_REG_ADDR_16(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_16))
+
+#define LTSSM_STATUS		0x0404
+#define  LTSSM_STATUS_L0_MASK	0x3f
+#define  LTSSM_STATUS_L0	0x2d
+
+#define PAB_CTRL		0x0808
+#define  AMBA_PIO_ENABLE_SHIFT	0
+#define  PEX_PIO_ENABLE_SHIFT	1
+#define  PAGE_SEL_SHIFT		13
+#define  PAGE_SEL_MASK		0x3f
+#define  PAGE_LO_MASK		0x3ff
+#define  PAGE_SEL_EN		0xc00
+#define  PAGE_SEL_OFFSET_SHIFT	10
+
+#define PAB_AXI_PIO_CTRL	0x0840
+#define  APIO_EN_MASK		0xf
+
+#define PAB_PEX_PIO_CTRL	0x08c0
+#define  PIO_ENABLE_SHIFT	0
+
+#define PAB_INTP_AMBA_MISC_ENB	0x0b0c
+#define PAB_INTP_AMBA_MISC_STAT	0x0b1c
+#define  PAB_INTP_INTX_MASK	0x1e0
+
+#define PAB_AXI_AMAP_CTRL(win)	PAB_REG_ADDR_16(0x0ba0, win)
+#define  WIN_ENABLE_SHIFT	0
+#define  WIN_TYPE_SHIFT		1
+#define  WIN_SIZE_SHIFT		10
+
+#define PAB_EXT_AXI_AMAP_SIZE(win)	PAB_REG_ADDR_4(0xbaf0, win)
+
+#define PAB_AXI_AMAP_AXI_WIN(win)	PAB_REG_ADDR_16(0x0ba4, win)
+#define  AXI_WINDOW_BASE_SHIFT		2
+
+#define PAB_AXI_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR_16(0x0ba8, win)
+#define  PAB_BUS_SHIFT			24
+#define  PAB_DEVICE_SHIFT		19
+#define  PAB_FUNCTION_SHIFT		16
+
+#define PAB_AXI_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR_16(0x0bac, win)
+#define PAB_INTP_AXI_PIO_CLASS		0x474
+
+#define PAB_PEX_AMAP_CTRL(win)		PAB_REG_ADDR_16(0x4ba0, win)
+#define  AMAP_CTRL_EN_SHIFT		0
+#define  AMAP_CTRL_TYPE_SHIFT		1
+
+#define PAB_EXT_PEX_AMAP_SIZEN(win)	PAB_REG_ADDR_4(0xbef0, win)
+#define PAB_PEX_AMAP_AXI_WIN(win)	PAB_REG_ADDR_16(0x4ba4, win)
+#define PAB_PEX_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR_16(0x4ba8, win)
+#define PAB_PEX_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR_16(0x4bac, win)
+
+/* supported number of interrupts */
+#define PCI_NUM_INTX		4
+#define PAB_INTA_POS		5
+
+/* outbound and inbound window definitions */
+#define WIN_NUM_0		0
+#define WIN_NUM_1		1
+#define CFG_WINDOW_TYPE		0
+#define IO_WINDOW_TYPE		1
+#define MEM_WINDOW_TYPE		2
+#define IB_WIN_SIZE		(256 * 1024 * 1024)
+#define MAX_PIO_WINDOWS		8
+
+/* Parameters for the waiting for link up routine */
+#define LINK_WAIT_MAX_RETRIES	10
+#define LINK_WAIT_MIN		90000
+#define LINK_WAIT_MAX		100000
+
+#ifndef UINT64_MAX
+#define UINT64_MAX		(u64)(~((u64)0))
+#endif
+
+struct mobiveil_pcie {
+	struct platform_device *pdev;
+	struct list_head resources;
+	void __iomem *config_axi_slave_base;	/* endpoint config base */
+	void __iomem *csr_axi_slave_base;	/* root port config base */
+	struct irq_domain *intx_domain;
+	int irq;
+	int apio_wins;
+	int ppio_wins;
+	int ob_wins_configured;	/*  configured outbound windows */
+	int ib_wins_configured;	/*  configured inbound windows */
+	struct resource *ob_io_res;
+	char root_bus_nr;
+};
+
+static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
+		const u32 reg)
+{
+	writel_relaxed(value, pcie->csr_axi_slave_base + reg);
+}
+
+static inline u32 csr_readl(struct mobiveil_pcie *pcie,	const u32 reg)
+{
+	return readl_relaxed(pcie->csr_axi_slave_base + reg);
+}
+
+static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
+{
+	return (csr_readl(pcie, LTSSM_STATUS) &
+		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
+}
+
+static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	/* Check if link is up when trying to access downstream ports */
+	if (bus->number != pcie->root_bus_nr)
+		if (!mobiveil_pcie_link_up(pcie))
+			return false;
+
+	/* Only one device down on each root port */
+	if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	/*
+	 * Do not read more than one device on the bus directly
+	 * attached to RC
+	 */
+	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	return true;
+}
+
+/*
+ * mobiveil_pcie_map_bus - routine to get the configuration base of either
+ * root port or endpoint
+ */
+static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
+					unsigned int devfn, int where)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	if (!mobiveil_pcie_valid_device(bus, devfn))
+		return NULL;
+
+	if (bus->number == pcie->root_bus_nr) {
+		/* RC config access */
+		return pcie->csr_axi_slave_base + where;
+	} else {
+		/*
+		 * EP config access (in Config/APIO space)
+		 * Program PEX Address base (31..16 bits) with appropriate value
+		 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
+		 * Relies on pci_lock serialization
+		 */
+		csr_writel(pcie,
+			bus->number << PAB_BUS_SHIFT |
+			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
+			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
+			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
+		return pcie->config_axi_slave_base + where;
+	}
+}
+
+static struct pci_ops mobiveil_pcie_ops = {
+	.map_bus = mobiveil_pcie_map_bus,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static void mobiveil_pcie_isr(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
+	struct device *dev = &pcie->pdev->dev;
+	u32 intr_status;
+	unsigned long shifted_status;
+	u32 bit, virq;
+	u32 val, mask;
+
+	chained_irq_enter(chip, desc);
+
+	/* read INTx status */
+	val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
+	mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	intr_status = val & mask;
+
+	/* Handle INTx */
+	if (intr_status & PAB_INTP_INTX_MASK) {
+		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
+		do {
+			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
+
+				/* clear interrupts */
+				csr_writel(pcie, shifted_status << PAB_INTA_POS,
+						PAB_INTP_AMBA_MISC_STAT);
+
+				virq = irq_find_mapping(pcie->intx_domain,
+					bit + 1);
+				if (virq)
+					generic_handle_irq(virq);
+				else
+					dev_err_ratelimited(dev,
+						"unexpected IRQ, INT%d\n",
+						bit);
+
+			}
+
+			shifted_status = csr_readl(pcie,
+						PAB_INTP_AMBA_MISC_STAT);
+
+		} while ((shifted_status >>  PAB_INTA_POS) != 0);
+	}
+
+	csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);
+	chained_irq_exit(chip, desc);
+}
+
+static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct platform_device *pdev = pcie->pdev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	const char *type;
+
+	type = of_get_property(node, "device_type", NULL);
+	if (!type || strcmp(type, "pci")) {
+		dev_err(dev, "invalid \"device_type\" %s\n", type);
+		return -EINVAL;
+	}
+
+	/* map config resource */
+	res = platform_get_resource_byname(pdev,
+		IORESOURCE_MEM, "config_axi_slave");
+	pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->config_axi_slave_base))
+		return PTR_ERR(pcie->config_axi_slave_base);
+	pcie->ob_io_res = res;
+
+	/* map csr resource */
+	res = platform_get_resource_byname(pdev,
+		IORESOURCE_MEM, "csr_axi_slave");
+	pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->csr_axi_slave_base))
+		return PTR_ERR(pcie->csr_axi_slave_base);
+
+	/* read the number of windows requested */
+	if (!pcie->apio_wins &&
+		of_property_read_u32(node, "apio-wins", &pcie->apio_wins)) {
+		pcie->apio_wins = MAX_PIO_WINDOWS;
+	}
+
+	if (!pcie->ppio_wins &&
+		of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins)) {
+		pcie->ppio_wins = MAX_PIO_WINDOWS;
+	}
+
+	pcie->irq = platform_get_irq(pdev, 0);
+	if (pcie->irq <= 0) {
+		dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
+		return -ENODEV;
+	}
+
+	irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
+
+	return 0;
+}
+
+/*
+ * select_paged_register - routine to access paged register of root complex
+ *
+ * registers of RC are paged, for this scheme to work
+ * extracted higher 6 bits of the offset will be written to pg_sel
+ * field of PAB_CTRL register and rest of the lower 10 bits enabled with
+ * PAGE_SEL_EN are used as offset of the register.
+ *
+ */
+static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	int pab_ctrl_dw, pg_sel;
+
+	/* clear pg_sel field */
+	pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
+	pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
+
+	/* set pg_sel field */
+	pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
+	pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
+	csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
+}
+
+static void write_paged_register(struct mobiveil_pcie *pcie,
+		u32 val, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	csr_writel(pcie, val, off);
+}
+
+static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	return csr_readl(pcie, off);
+}
+
+static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
+		int pci_addr, int type,	int size_kb)
+{
+	int pio_ctrl_val;
+	int amap_ctrl_dw;
+	u64 size64 = (UINT64_MAX << (WIN_SIZE_SHIFT + ilog2(size_kb)));
+
+	if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max inbound windows reached !\n");
+		return;
+	}
+
+	pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
+	csr_writel(pcie,
+		pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
+	amap_ctrl_dw =	read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
+	amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
+	amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
+
+	write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
+				PAB_PEX_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_PEX_AMAP_SIZEN(win_num));
+
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
+	write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
+}
+
+static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
+		u64 cpu_addr, u64 pci_addr, int config_io_bit,
+		int size_kb)
+{
+
+	u32 value, type;
+	u64 size64 = (UINT64_MAX << (WIN_SIZE_SHIFT + ilog2(size_kb)));
+
+	if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max outbound windows reached !\n");
+		return;
+	}
+
+	/*
+	 * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
+	 * to 4 KB in PAB_AXI_AMAP_CTRL register
+	 */
+	type = config_io_bit;
+	value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
+	csr_writel(pcie,
+			1 << WIN_ENABLE_SHIFT |
+			type << WIN_TYPE_SHIFT |
+			lower_32_bits(size64),
+			PAB_AXI_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_AXI_AMAP_SIZE(win_num));
+
+	/*
+	 * program AXI window base with appropriate value in
+	 * PAB_AXI_AMAP_AXI_WIN0 register
+	 */
+	value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
+	csr_writel(pcie,
+			cpu_addr >> AXI_WINDOW_BASE_SHIFT <<
+			AXI_WINDOW_BASE_SHIFT, PAB_AXI_AMAP_AXI_WIN(win_num));
+
+	value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	csr_writel(pcie, lower_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_L(win_num));
+	csr_writel(pcie, upper_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	pcie->ob_wins_configured++;
+}
+
+static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
+{
+	int retries;
+
+	/* check if the link is up or not */
+	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+		if (mobiveil_pcie_link_up(pcie))
+			return 0;
+
+		usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
+	}
+	dev_err(&pcie->pdev->dev, "link never came up\n");
+	return -ETIMEDOUT;
+}
+
+static int mobiveil_host_init(struct mobiveil_pcie *pcie)
+{
+	u32 value;
+	int type = 0;
+	u32 pab_ctrl;
+	int err;
+	struct resource_entry *win, *tmp;
+
+	/* setup the PCIe slot link power*/
+
+	err = mobiveil_bringup_link(pcie);
+	if (err) {
+		dev_info(&pcie->pdev->dev, "link bring-up failed\n");
+		return err;
+	}
+
+	/*
+	 * program Bus Master Enable Bit in Command Register in PAB Config
+	 * Space
+	 */
+	value = csr_readl(pcie, PCI_COMMAND);
+	csr_writel(pcie,
+		value |
+		PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
+		PCI_COMMAND);
+
+	/*
+	 * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
+	 * register
+	 */
+	pab_ctrl = csr_readl(pcie, PAB_CTRL);
+	csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
+		(1 << PEX_PIO_ENABLE_SHIFT),
+		PAB_CTRL);
+
+	csr_writel(pcie, PAB_INTP_INTX_MASK, PAB_INTP_AMBA_MISC_ENB);
+
+	/* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
+	 * PAB_AXI_PIO_CTRL Register
+	 */
+	value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
+	csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
+
+	/*
+	 * we'll program one outbound window for config reads and
+	 * another default inbound window for all the upstream traffic
+	 * rest of the outbound windows will be configured according to
+	 * the "ranges" field defined in device tree
+	 */
+
+	/* config outbound translation window */
+	program_ob_windows(pcie, pcie->ob_wins_configured,
+			pcie->ob_io_res->start,	0, CFG_WINDOW_TYPE,
+			resource_size(pcie->ob_io_res)/1024);
+
+	/* memory inbound  translation window */
+	program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
+
+	/* Get the I/O and memory ranges from DT */
+	resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
+		type = 0;
+		if (resource_type(win->res) == IORESOURCE_MEM)
+			type = MEM_WINDOW_TYPE;
+		if (resource_type(win->res) == IORESOURCE_IO)
+			type = IO_WINDOW_TYPE;
+		if (type) {
+			/* configure outbound translation window */
+			program_ob_windows(pcie, pcie->ob_wins_configured,
+				win->res->start, 0, type,
+				resource_size(win->res)/1024);
+		}
+	}
+
+	return err;
+}
+
+/* routine to setup the INTx related data */
+static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
+		irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	return 0;
+}
+
+/* INTx domain opeartions structure */
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = mobiveil_pcie_intx_map,
+};
+
+static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+
+	/* setup INTx */
+	pcie->intx_domain = irq_domain_add_linear(node,
+				PCI_NUM_INTX + 1, &intx_domain_ops, pcie);
+
+	if (!pcie->intx_domain) {
+		dev_err(dev, "Failed to get a INTx IRQ domain\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int mobiveil_pcie_probe(struct platform_device *pdev)
+{
+	struct mobiveil_pcie *pcie;
+	struct pci_bus *bus;
+	struct pci_bus *child;
+	struct pci_host_bridge *bridge;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	resource_size_t iobase;
+	int ret;
+
+	/* allocate the PCIe port */
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	if (!bridge)
+		return -ENODEV;
+
+	pcie = pci_host_bridge_priv(bridge);
+	if (!pcie)
+		return -ENOMEM;
+
+	pcie->pdev = pdev;
+
+	/* parse the device tree */
+	ret = mobiveil_pcie_parse_dt(pcie);
+	if (ret) {
+		dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
+		return ret;
+	}
+
+	INIT_LIST_HEAD(&pcie->resources);
+
+	/* parse the host bridge base addresses from the device tree file */
+	ret = of_pci_get_host_bridge_resources(node,
+			0, 0xff, &pcie->resources, &iobase);
+	if (ret) {
+		dev_err(dev, "Getting bridge resources failed\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * configure all inbound and outbound windows and prepare the RC for
+	 * config access
+	 */
+	ret = mobiveil_host_init(pcie);
+	if (ret) {
+		dev_err(dev, "Failed to initialize host\n");
+		goto error;
+	}
+
+	/* fixup for PCIe class register */
+	csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
+
+	/* initialize the IRQ domains */
+	ret = mobiveil_pcie_init_irq_domain(pcie);
+	if (ret) {
+		dev_err(dev, "Failed creating IRQ Domain\n");
+		goto error;
+	}
+
+
+	ret = devm_request_pci_bus_resources(dev, &pcie->resources);
+	if (ret)
+		goto error;
+
+	/* Initialize bridge */
+	list_splice_init(&pcie->resources, &bridge->windows);
+	bridge->dev.parent = dev;
+	bridge->sysdata = pcie;
+	bridge->busnr = pcie->root_bus_nr;
+	bridge->ops = &mobiveil_pcie_ops;
+	bridge->map_irq = of_irq_parse_and_map_pci;
+	bridge->swizzle_irq = pci_common_swizzle;
+
+	/* setup the kernel resources for the newly added PCIe root bus */
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret)
+		goto error;
+
+	bus = bridge->bus;
+
+	pci_assign_unassigned_bus_resources(bus);
+	list_for_each_entry(child, &bus->children, node)
+		pcie_bus_configure_settings(child);
+	pci_bus_add_devices(bus);
+
+	platform_set_drvdata(pdev, pcie);
+
+	return 0;
+error:
+	pci_free_resource_list(&pcie->resources);
+	return ret;
+}
+
+static const struct of_device_id mobiveil_pcie_of_match[] = {
+	{.compatible = "mbvl,gpex40-pcie",},
+};
+
+MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
+
+static struct platform_driver mobiveil_pcie_driver = {
+	.probe = mobiveil_pcie_probe,
+	.driver = {
+			.name = "mobiveil-pcie",
+			.of_match_table = mobiveil_pcie_of_match,
+			.suppress_bind_attrs = true,
+		},
+};
+
+builtin_platform_driver(mobiveil_pcie_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
+MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>");
-- 
1.8.3.1

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Re: [PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Lorenzo Pieralisi]

On Wed, Dec 13, 2017 at 11:08:37AM -0500, Subrahmanya Lingappa wrote:
> Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP -
> GPEX 4.0, a PCIe gen4 IP. This IP has upto 8
> outbound and inbound windows for the address translation.
> 
> Signed-off-by: Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>
> Cc: Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
> Cc: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>
> Cc: linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  drivers/pci/host/Kconfig         |   8 +
>  drivers/pci/host/Makefile        |   1 +
>  drivers/pci/host/pcie-mobiveil.c | 653 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 662 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-mobiveil.c
> 
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 38d1298..09bf1d9 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -27,6 +27,14 @@ config PCIE_XILINX_NWL
>  	 or End Point. The current option selection will only
>  	 support root port enabling.
>  
> +config PCIE_MOBIVEIL
> +        bool "Mobiveil AXI PCIe host bridge support"
> +        depends on ARCH_ZYNQMP || COMPILE_TEST
> +        depends on PCI_MSI_IRQ_DOMAIN

There is no PCI_MSI_IRQ_DOMAIN dependency in this patch.

> +        help
> +          Say 'Y' here if you want kernel to support the Mobiveil AXI PCIe
> +          Host Bridge driver.
> +
>  config PCI_FTPCI100
>  	bool "Faraday Technology FTPCI100 PCI controller"
>  	depends on OF
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 34ec1d8..d745d68 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_PCIE_ROCKCHIP) += pcie-rockchip.o
>  obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o
>  obj-$(CONFIG_PCIE_TANGO_SMP8759) += pcie-tango.o
>  obj-$(CONFIG_VMD) += vmd.o
> +obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
>  
>  # The following drivers are for devices that use the generic ACPI
>  # pci_root.c driver but don't support standard ECAM config access.
> diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
> new file mode 100644
> index 0000000..8611aaa
> --- /dev/null
> +++ b/drivers/pci/host/pcie-mobiveil.c
> @@ -0,0 +1,653 @@
> +/*
> + * PCIe host controller driver for Mobiveil PCIe Host controller
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + * Copyright (c) 2017 Mobiveil Inc.
> + * Author: Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/init.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_pci.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +/* register offsets and bit positions */
> +
> +/*
> + * translation tables are grouped into windows, each window registers are
> + * grouped into blocks of 4 or 16 registers each
> + */
> +#define PAB_REG_BLOCK_SIZE_4	4
> +#define PAB_REG_BLOCK_SIZE_16	16

What I wanted to say is that you can tag the block with a name
instead of using a number.

I can say that block size 4 is only for PAB_EXT_*, you can tag
it as such.

eg PAB_EXT_REG_BLOCK_SIZE

> +#define PAB_REG_ADDR_4(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_4))
> +#define PAB_REG_ADDR_16(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_16))
> +
> +#define LTSSM_STATUS		0x0404
> +#define  LTSSM_STATUS_L0_MASK	0x3f
> +#define  LTSSM_STATUS_L0	0x2d
> +
> +#define PAB_CTRL		0x0808
> +#define  AMBA_PIO_ENABLE_SHIFT	0
> +#define  PEX_PIO_ENABLE_SHIFT	1
> +#define  PAGE_SEL_SHIFT		13
> +#define  PAGE_SEL_MASK		0x3f
> +#define  PAGE_LO_MASK		0x3ff
> +#define  PAGE_SEL_EN		0xc00
> +#define  PAGE_SEL_OFFSET_SHIFT	10
> +
> +#define PAB_AXI_PIO_CTRL	0x0840
> +#define  APIO_EN_MASK		0xf
> +
> +#define PAB_PEX_PIO_CTRL	0x08c0
> +#define  PIO_ENABLE_SHIFT	0
> +
> +#define PAB_INTP_AMBA_MISC_ENB	0x0b0c
> +#define PAB_INTP_AMBA_MISC_STAT	0x0b1c
> +#define  PAB_INTP_INTX_MASK	0x1e0
> +
> +#define PAB_AXI_AMAP_CTRL(win)	PAB_REG_ADDR_16(0x0ba0, win)
> +#define  WIN_ENABLE_SHIFT	0
> +#define  WIN_TYPE_SHIFT		1
> +#define  WIN_SIZE_SHIFT		10
> +
> +#define PAB_EXT_AXI_AMAP_SIZE(win)	PAB_REG_ADDR_4(0xbaf0, win)
> +
> +#define PAB_AXI_AMAP_AXI_WIN(win)	PAB_REG_ADDR_16(0x0ba4, win)
> +#define  AXI_WINDOW_BASE_SHIFT		2
> +
> +#define PAB_AXI_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR_16(0x0ba8, win)
> +#define  PAB_BUS_SHIFT			24
> +#define  PAB_DEVICE_SHIFT		19
> +#define  PAB_FUNCTION_SHIFT		16
> +
> +#define PAB_AXI_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR_16(0x0bac, win)
> +#define PAB_INTP_AXI_PIO_CLASS		0x474

This one is a bit odd here, move it up in the file.

> +#define PAB_PEX_AMAP_CTRL(win)		PAB_REG_ADDR_16(0x4ba0, win)
> +#define  AMAP_CTRL_EN_SHIFT		0
> +#define  AMAP_CTRL_TYPE_SHIFT		1
> +
> +#define PAB_EXT_PEX_AMAP_SIZEN(win)	PAB_REG_ADDR_4(0xbef0, win)
> +#define PAB_PEX_AMAP_AXI_WIN(win)	PAB_REG_ADDR_16(0x4ba4, win)
> +#define PAB_PEX_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR_16(0x4ba8, win)
> +#define PAB_PEX_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR_16(0x4bac, win)

Here you have three base offsets:

0xb00
0x4000
0xb000

you can create a macro for each of them, according to what they
represent and then add an offset into each.

> +
> +/* supported number of interrupts */
> +#define PCI_NUM_INTX		4

It is already defined in linux/pci.h

> +#define PAB_INTA_POS		5
> +
> +/* outbound and inbound window definitions */
> +#define WIN_NUM_0		0
> +#define WIN_NUM_1		1
> +#define CFG_WINDOW_TYPE		0
> +#define IO_WINDOW_TYPE		1
> +#define MEM_WINDOW_TYPE		2
> +#define IB_WIN_SIZE		(256 * 1024 * 1024)
> +#define MAX_PIO_WINDOWS		8
> +
> +/* Parameters for the waiting for link up routine */
> +#define LINK_WAIT_MAX_RETRIES	10
> +#define LINK_WAIT_MIN		90000
> +#define LINK_WAIT_MAX		100000
> +
> +#ifndef UINT64_MAX
> +#define UINT64_MAX		(u64)(~((u64)0))
> +#endif
> +
> +struct mobiveil_pcie {
> +	struct platform_device *pdev;
> +	struct list_head resources;
> +	void __iomem *config_axi_slave_base;	/* endpoint config base */
> +	void __iomem *csr_axi_slave_base;	/* root port config base */
> +	struct irq_domain *intx_domain;
> +	int irq;
> +	int apio_wins;
> +	int ppio_wins;
> +	int ob_wins_configured;	/*  configured outbound windows */
> +	int ib_wins_configured;	/*  configured inbound windows */
> +	struct resource *ob_io_res;
> +	char root_bus_nr;
> +};
> +
> +static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
> +		const u32 reg)
> +{
> +	writel_relaxed(value, pcie->csr_axi_slave_base + reg);
> +}
> +
> +static inline u32 csr_readl(struct mobiveil_pcie *pcie,	const u32 reg)
> +{
> +	return readl_relaxed(pcie->csr_axi_slave_base + reg);
> +}
> +
> +static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
> +{
> +	return (csr_readl(pcie, LTSSM_STATUS) &
> +		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
> +}

https://marc.info/?l=linux-pci&m=151329230814614&w=2

Bjorn would like to remove it.

> +static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
> +{
> +	struct mobiveil_pcie *pcie = bus->sysdata;
> +
> +	/* Check if link is up when trying to access downstream ports */
> +	if (bus->number != pcie->root_bus_nr)
> +		if (!mobiveil_pcie_link_up(pcie))
> +			return false;
> +
> +	/* Only one device down on each root port */
> +	if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
> +		return false;
> +
> +	/*
> +	 * Do not read more than one device on the bus directly
> +	 * attached to RC
> +	 */
> +	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
> +		return false;
> +
> +	return true;
> +}
> +
> +/*
> + * mobiveil_pcie_map_bus - routine to get the configuration base of either
> + * root port or endpoint
> + */
> +static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
> +					unsigned int devfn, int where)
> +{
> +	struct mobiveil_pcie *pcie = bus->sysdata;
> +
> +	if (!mobiveil_pcie_valid_device(bus, devfn))
> +		return NULL;
> +
> +	if (bus->number == pcie->root_bus_nr) {
> +		/* RC config access */
> +		return pcie->csr_axi_slave_base + where;
> +	} else {
> +		/*
> +		 * EP config access (in Config/APIO space)
> +		 * Program PEX Address base (31..16 bits) with appropriate value
> +		 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
> +		 * Relies on pci_lock serialization
> +		 */
> +		csr_writel(pcie,
> +			bus->number << PAB_BUS_SHIFT |
> +			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
> +			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
> +			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
> +		return pcie->config_axi_slave_base + where;
> +	}
> +}
> +
> +static struct pci_ops mobiveil_pcie_ops = {
> +	.map_bus = mobiveil_pcie_map_bus,
> +	.read = pci_generic_config_read,
> +	.write = pci_generic_config_write,
> +};
> +
> +static void mobiveil_pcie_isr(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
> +	struct device *dev = &pcie->pdev->dev;
> +	u32 intr_status;
> +	unsigned long shifted_status;

Why not u32 ?

> +	u32 bit, virq;
> +	u32 val, mask;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	/* read INTx status */
> +	val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> +	mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> +	intr_status = val & mask;
> +
> +	/* Handle INTx */
> +	if (intr_status & PAB_INTP_INTX_MASK) {
> +		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);

Why can't you reuse val to read the status and create shifted_status
from it ?

eg

shifted_status = val << PAB_INTA_POS;
csr_writel(pcie, shifted_status, PAB_INTP_AMBA_MISC_STAT);

Just a hint to make the loop more readable. BTW, I do not think that
writing shifted_status into that register is OK, see below.

> +		do {
> +			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
> +
> +				/* clear interrupts */
> +				csr_writel(pcie, shifted_status << PAB_INTA_POS,
> +						PAB_INTP_AMBA_MISC_STAT);

Should not you clear just the interrupt you are about to handle ?

> +				virq = irq_find_mapping(pcie->intx_domain,
> +					bit + 1);
> +				if (virq)
> +					generic_handle_irq(virq);
> +				else
> +					dev_err_ratelimited(dev,
> +						"unexpected IRQ, INT%d\n",
> +						bit);
> +
> +			}
> +
> +			shifted_status = csr_readl(pcie,
> +						PAB_INTP_AMBA_MISC_STAT);
> +
> +		} while ((shifted_status >>  PAB_INTA_POS) != 0);

I do not understand this. Can you explain to me how the
register at:

PAB_INTP_AMBA_MISC_STAT

works ?

A patch for mediatek has been posted:

https://patchwork.ozlabs.org/patch/851181/

It looks like this loop may suffer from the same issue, so please do
have a look.

On top of that, most of the operations you are carrying out here
can be done automatically by making them part of the struct irq_chip
methods (ie acking IRQs, masking IRQs, etc, see below).

> +	}
> +
> +	csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);

> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
> +{
> +	struct device *dev = &pcie->pdev->dev;
> +	struct platform_device *pdev = pcie->pdev;
> +	struct device_node *node = dev->of_node;
> +	struct resource *res;
> +	const char *type;
> +
> +	type = of_get_property(node, "device_type", NULL);
> +	if (!type || strcmp(type, "pci")) {
> +		dev_err(dev, "invalid \"device_type\" %s\n", type);
> +		return -EINVAL;
> +	}
> +
> +	/* map config resource */
> +	res = platform_get_resource_byname(pdev,
> +		IORESOURCE_MEM, "config_axi_slave");
> +	pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> +	if (IS_ERR(pcie->config_axi_slave_base))
> +		return PTR_ERR(pcie->config_axi_slave_base);
> +	pcie->ob_io_res = res;
> +
> +	/* map csr resource */
> +	res = platform_get_resource_byname(pdev,
> +		IORESOURCE_MEM, "csr_axi_slave");
> +	pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> +	if (IS_ERR(pcie->csr_axi_slave_base))
> +		return PTR_ERR(pcie->csr_axi_slave_base);
> +
> +	/* read the number of windows requested */
> +	if (!pcie->apio_wins &&
> +		of_property_read_u32(node, "apio-wins", &pcie->apio_wins)) {
> +		pcie->apio_wins = MAX_PIO_WINDOWS;
> +	}
> +
> +	if (!pcie->ppio_wins &&

What I wanted to say in my previous review is that apio_wins and
ppio_wins are zero here why would they be any different and why
do you need to check that.

> +		of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins)) {
> +		pcie->ppio_wins = MAX_PIO_WINDOWS;
> +	}
> +
> +	pcie->irq = platform_get_irq(pdev, 0);
> +	if (pcie->irq <= 0) {
> +		dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
> +		return -ENODEV;
> +	}
> +
> +	irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
> +
> +	return 0;
> +}
> +
> +/*
> + * select_paged_register - routine to access paged register of root complex
> + *
> + * registers of RC are paged, for this scheme to work
> + * extracted higher 6 bits of the offset will be written to pg_sel
> + * field of PAB_CTRL register and rest of the lower 10 bits enabled with
> + * PAGE_SEL_EN are used as offset of the register.
> + *
> + */
> +static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> +{
> +	int pab_ctrl_dw, pg_sel;
> +
> +	/* clear pg_sel field */
> +	pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
> +	pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
> +
> +	/* set pg_sel field */
> +	pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
> +	pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
> +	csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
> +}
> +
> +static void write_paged_register(struct mobiveil_pcie *pcie,
> +		u32 val, u32 offset)
> +{
> +	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> +
> +	select_paged_register(pcie, offset);
> +	csr_writel(pcie, val, off);
> +}
> +
> +static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> +{
> +	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> +
> +	select_paged_register(pcie, offset);
> +	return csr_readl(pcie, off);
> +}
> +
> +static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
> +		int pci_addr, int type,	int size_kb)
> +{
> +	int pio_ctrl_val;
> +	int amap_ctrl_dw;
> +	u64 size64 = (UINT64_MAX << (WIN_SIZE_SHIFT + ilog2(size_kb)));
> +
> +	if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
> +		dev_err(&pcie->pdev->dev,
> +			"ERROR: max inbound windows reached !\n");
> +		return;
> +	}
> +
> +	pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
> +	csr_writel(pcie,
> +		pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
> +	amap_ctrl_dw =	read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
> +	amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
> +	amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
> +
> +	write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
> +				PAB_PEX_AMAP_CTRL(win_num));
> +
> +	write_paged_register(pcie, upper_32_bits(size64),
> +				PAB_EXT_PEX_AMAP_SIZEN(win_num));
> +
> +	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
> +	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
> +	write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
> +}
> +
> +static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
> +		u64 cpu_addr, u64 pci_addr, int config_io_bit,
> +		int size_kb)
> +{
> +
> +	u32 value, type;
> +	u64 size64 = (UINT64_MAX << (WIN_SIZE_SHIFT + ilog2(size_kb)));

Can you explain to me the sizing mechanism please ? It is just to make
sure I got it right.

> +	if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
> +		dev_err(&pcie->pdev->dev,
> +			"ERROR: max outbound windows reached !\n");
> +		return;
> +	}
> +
> +	/*
> +	 * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
> +	 * to 4 KB in PAB_AXI_AMAP_CTRL register
> +	 */
> +	type = config_io_bit;
> +	value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
> +	csr_writel(pcie,
> +			1 << WIN_ENABLE_SHIFT |
> +			type << WIN_TYPE_SHIFT |
> +			lower_32_bits(size64),
> +			PAB_AXI_AMAP_CTRL(win_num));
> +
> +	write_paged_register(pcie, upper_32_bits(size64),
> +				PAB_EXT_AXI_AMAP_SIZE(win_num));
> +
> +	/*
> +	 * program AXI window base with appropriate value in
> +	 * PAB_AXI_AMAP_AXI_WIN0 register
> +	 */
> +	value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
> +	csr_writel(pcie,
> +			cpu_addr >> AXI_WINDOW_BASE_SHIFT <<
> +			AXI_WINDOW_BASE_SHIFT, PAB_AXI_AMAP_AXI_WIN(win_num));
> +
> +	value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));

What's "value" used for in this function ?

> +	csr_writel(pcie, lower_32_bits(pci_addr),
> +			PAB_AXI_AMAP_PEX_WIN_L(win_num));
> +	csr_writel(pcie, upper_32_bits(pci_addr),
> +			PAB_AXI_AMAP_PEX_WIN_H(win_num));
> +
> +	pcie->ob_wins_configured++;
> +}
> +
> +static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
> +{
> +	int retries;
> +
> +	/* check if the link is up or not */
> +	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
> +		if (mobiveil_pcie_link_up(pcie))
> +			return 0;
> +
> +		usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
> +	}
> +	dev_err(&pcie->pdev->dev, "link never came up\n");
> +	return -ETIMEDOUT;
> +}
> +
> +static int mobiveil_host_init(struct mobiveil_pcie *pcie)
> +{
> +	u32 value;
> +	int type = 0;

You reinitialize it later and it should not be an int but an unsigned
type.

> +	u32 pab_ctrl;
> +	int err;
> +	struct resource_entry *win, *tmp;
> +
> +	/* setup the PCIe slot link power*/

Comment is useless, remove it.

> +	err = mobiveil_bringup_link(pcie);
> +	if (err) {
> +		dev_info(&pcie->pdev->dev, "link bring-up failed\n");
> +		return err;
> +	}
> +
> +	/*
> +	 * program Bus Master Enable Bit in Command Register in PAB Config
> +	 * Space
> +	 */
> +	value = csr_readl(pcie, PCI_COMMAND);
> +	csr_writel(pcie,
> +		value |

Why is this on a separate line ?

> +		PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
> +		PCI_COMMAND);
> +
> +	/*
> +	 * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
> +	 * register
> +	 */
> +	pab_ctrl = csr_readl(pcie, PAB_CTRL);
> +	csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
> +		(1 << PEX_PIO_ENABLE_SHIFT),
> +		PAB_CTRL);
> +
> +	csr_writel(pcie, PAB_INTP_INTX_MASK, PAB_INTP_AMBA_MISC_ENB);
> +
> +	/* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
> +	 * PAB_AXI_PIO_CTRL Register
> +	 */
> +	value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
> +	csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
> +
> +	/*
> +	 * we'll program one outbound window for config reads and
> +	 * another default inbound window for all the upstream traffic
> +	 * rest of the outbound windows will be configured according to
> +	 * the "ranges" field defined in device tree
> +	 */
> +
> +	/* config outbound translation window */
> +	program_ob_windows(pcie, pcie->ob_wins_configured,
> +			pcie->ob_io_res->start,	0, CFG_WINDOW_TYPE,
> +			resource_size(pcie->ob_io_res)/1024);
> +
> +	/* memory inbound  translation window */
> +	program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
> +
> +	/* Get the I/O and memory ranges from DT */
> +	resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
> +		type = 0;
> +		if (resource_type(win->res) == IORESOURCE_MEM)
> +			type = MEM_WINDOW_TYPE;
> +		if (resource_type(win->res) == IORESOURCE_IO)
> +			type = IO_WINDOW_TYPE;
> +		if (type) {
> +			/* configure outbound translation window */
> +			program_ob_windows(pcie, pcie->ob_wins_configured,
> +				win->res->start, 0, type,
> +				resource_size(win->res)/1024);
> +		}
> +	}
> +
> +	return err;
> +}
> +
> +/* routine to setup the INTx related data */
> +static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> +		irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);

IIUC, the host bridge acts as an INTX/MSI controller/multiplexer.

So, instead of relying on dummy_irq_chip, you should create your own
irq_chip with the methods that you require (eg irq_ack(), irq_mask(),
irq_compose_msi_msg()) and use that as bottom irq_chip for both
INTX and MSI domains.

That's why I asked you to have a look at pcie-tango.c (except that there
INTX aren't supported but the basic idea does not change) and implement
IRQ domains handling like that same driver.

> +	irq_set_chip_data(irq, domain->host_data);
> +	return 0;
> +}
> +
> +/* INTx domain opeartions structure */

s/opeartions/operations

> +static const struct irq_domain_ops intx_domain_ops = {
> +	.map = mobiveil_pcie_intx_map,
> +};
> +
> +static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
> +{
> +	struct device *dev = &pcie->pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	int ret;

ret is unused

> +	/* setup INTx */
> +	pcie->intx_domain = irq_domain_add_linear(node,
> +				PCI_NUM_INTX + 1, &intx_domain_ops, pcie);

You should use PCI_NUM_INTX and add pci_irqd_intx_xlate() as the
domain ops .xlate.

> +	if (!pcie->intx_domain) {
> +		dev_err(dev, "Failed to get a INTx IRQ domain\n");
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mobiveil_pcie_probe(struct platform_device *pdev)
> +{
> +	struct mobiveil_pcie *pcie;
> +	struct pci_bus *bus;
> +	struct pci_bus *child;
> +	struct pci_host_bridge *bridge;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	resource_size_t iobase;
> +	int ret;
> +
> +	/* allocate the PCIe port */
> +	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> +	if (!bridge)
> +		return -ENODEV;
> +
> +	pcie = pci_host_bridge_priv(bridge);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pcie->pdev = pdev;
> +
> +	/* parse the device tree */

Remove this comment, it does not add anything.

> +	ret = mobiveil_pcie_parse_dt(pcie);
> +	if (ret) {
> +		dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
> +		return ret;
> +	}
> +
> +	INIT_LIST_HEAD(&pcie->resources);
> +
> +	/* parse the host bridge base addresses from the device tree file */
> +	ret = of_pci_get_host_bridge_resources(node,
> +			0, 0xff, &pcie->resources, &iobase);
> +	if (ret) {
> +		dev_err(dev, "Getting bridge resources failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	/*
> +	 * configure all inbound and outbound windows and prepare the RC for
> +	 * config access
> +	 */
> +	ret = mobiveil_host_init(pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize host\n");
> +		goto error;
> +	}
> +
> +	/* fixup for PCIe class register */
> +	csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
> +
> +	/* initialize the IRQ domains */
> +	ret = mobiveil_pcie_init_irq_domain(pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed creating IRQ Domain\n");
> +		goto error;
> +	}
> +
> +

Two empty lines, should be one.

> +	ret = devm_request_pci_bus_resources(dev, &pcie->resources);
> +	if (ret)
> +		goto error;
> +
> +	/* Initialize bridge */
> +	list_splice_init(&pcie->resources, &bridge->windows);
> +	bridge->dev.parent = dev;
> +	bridge->sysdata = pcie;
> +	bridge->busnr = pcie->root_bus_nr;
> +	bridge->ops = &mobiveil_pcie_ops;
> +	bridge->map_irq = of_irq_parse_and_map_pci;
> +	bridge->swizzle_irq = pci_common_swizzle;
> +
> +	/* setup the kernel resources for the newly added PCIe root bus */
> +	ret = pci_scan_root_bus_bridge(bridge);
> +	if (ret)
> +		goto error;
> +
> +	bus = bridge->bus;
> +
> +	pci_assign_unassigned_bus_resources(bus);
> +	list_for_each_entry(child, &bus->children, node)
> +		pcie_bus_configure_settings(child);
> +	pci_bus_add_devices(bus);
> +
> +	platform_set_drvdata(pdev, pcie);

Is this really needed ?

Thanks,
Lorenzo

> +
> +	return 0;
> +error:
> +	pci_free_resource_list(&pcie->resources);
> +	return ret;
> +}
> +
> +static const struct of_device_id mobiveil_pcie_of_match[] = {
> +	{.compatible = "mbvl,gpex40-pcie",},
> +};
> +
> +MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
> +
> +static struct platform_driver mobiveil_pcie_driver = {
> +	.probe = mobiveil_pcie_probe,
> +	.driver = {
> +			.name = "mobiveil-pcie",
> +			.of_match_table = mobiveil_pcie_of_match,
> +			.suppress_bind_attrs = true,
> +		},
> +};
> +
> +builtin_platform_driver(mobiveil_pcie_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
> +MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya-DTHOJn6Rh8lhmhkoCovsdw@public.gmane.org>");
> -- 
> 1.8.3.1
> 
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Re: [PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Subrahmanya Lingappa]

Lorenzo,

On Wed, Dec 20, 2017 at 10:33 PM, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Wed, Dec 13, 2017 at 11:08:37AM -0500, Subrahmanya Lingappa wrote:
> > Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP -
> > GPEX 4.0, a PCIe gen4 IP. This IP has upto 8
> > outbound and inbound windows for the address translation.
> >
> > Signed-off-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Marc Zyngier <marc.zyngier@arm.com>
> > Cc: linux-pci@vger.kernel.org
> > Cc: devicetree@vger.kernel.org
> > ---
> >  drivers/pci/host/Kconfig         |   8 +
> >  drivers/pci/host/Makefile        |   1 +
> >  drivers/pci/host/pcie-mobiveil.c | 653 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 662 insertions(+)
> >  create mode 100644 drivers/pci/host/pcie-mobiveil.c
> >
> > diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> > index 38d1298..09bf1d9 100644
> > --- a/drivers/pci/host/Kconfig
> > +++ b/drivers/pci/host/Kconfig
> > @@ -27,6 +27,14 @@ config PCIE_XILINX_NWL
> >        or End Point. The current option selection will only
> >        support root port enabling.
> >
> > +config PCIE_MOBIVEIL
> > +        bool "Mobiveil AXI PCIe host bridge support"
> > +        depends on ARCH_ZYNQMP || COMPILE_TEST
> > +        depends on PCI_MSI_IRQ_DOMAIN
>
> There is no PCI_MSI_IRQ_DOMAIN dependency in this patch.
>
> > +        help
> > +          Say 'Y' here if you want kernel to support the Mobiveil AXI PCIe
> > +          Host Bridge driver.
> > +
> >  config PCI_FTPCI100
> >       bool "Faraday Technology FTPCI100 PCI controller"
> >       depends on OF
> > diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> > index 34ec1d8..d745d68 100644
> > --- a/drivers/pci/host/Makefile
> > +++ b/drivers/pci/host/Makefile
> > @@ -23,6 +23,7 @@ obj-$(CONFIG_PCIE_ROCKCHIP) += pcie-rockchip.o
> >  obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o
> >  obj-$(CONFIG_PCIE_TANGO_SMP8759) += pcie-tango.o
> >  obj-$(CONFIG_VMD) += vmd.o
> > +obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
> >
> >  # The following drivers are for devices that use the generic ACPI
> >  # pci_root.c driver but don't support standard ECAM config access.
> > diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
> > new file mode 100644
> > index 0000000..8611aaa
> > --- /dev/null
> > +++ b/drivers/pci/host/pcie-mobiveil.c
> > @@ -0,0 +1,653 @@
> > +/*
> > + * PCIe host controller driver for Mobiveil PCIe Host controller
> > + *
> > + * SPDX-License-Identifier: GPL-2.0
> > + * Copyright (c) 2017 Mobiveil Inc.
> > + * Author: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/init.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip/chained_irq.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/of_pci.h>
> > +#include <linux/pci.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +/* register offsets and bit positions */
> > +
> > +/*
> > + * translation tables are grouped into windows, each window registers are
> > + * grouped into blocks of 4 or 16 registers each
> > + */
> > +#define PAB_REG_BLOCK_SIZE_4 4
> > +#define PAB_REG_BLOCK_SIZE_16        16
>
> What I wanted to say is that you can tag the block with a name
> instead of using a number.
>
> I can say that block size 4 is only for PAB_EXT_*, you can tag
> it as such.
>
> eg PAB_EXT_REG_BLOCK_SIZE

Ok, I'll rename them as below, and use them accordingly.

#define PAB_REG_BLOCK_SIZE 16
#define PAB_EXT_REG_BLOCK_SIZE 4

>
>
> > +#define PAB_REG_ADDR_4(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_4))
> > +#define PAB_REG_ADDR_16(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE_16))
> > +
> > +#define LTSSM_STATUS         0x0404
> > +#define  LTSSM_STATUS_L0_MASK        0x3f
> > +#define  LTSSM_STATUS_L0     0x2d
> > +
> > +#define PAB_CTRL             0x0808
> > +#define  AMBA_PIO_ENABLE_SHIFT       0
> > +#define  PEX_PIO_ENABLE_SHIFT        1
> > +#define  PAGE_SEL_SHIFT              13
> > +#define  PAGE_SEL_MASK               0x3f
> > +#define  PAGE_LO_MASK                0x3ff
> > +#define  PAGE_SEL_EN         0xc00
> > +#define  PAGE_SEL_OFFSET_SHIFT       10
> > +
> > +#define PAB_AXI_PIO_CTRL     0x0840
> > +#define  APIO_EN_MASK                0xf
> > +
> > +#define PAB_PEX_PIO_CTRL     0x08c0
> > +#define  PIO_ENABLE_SHIFT    0
> > +
> > +#define PAB_INTP_AMBA_MISC_ENB       0x0b0c
> > +#define PAB_INTP_AMBA_MISC_STAT      0x0b1c
> > +#define  PAB_INTP_INTX_MASK  0x1e0
> > +
> > +#define PAB_AXI_AMAP_CTRL(win)       PAB_REG_ADDR_16(0x0ba0, win)
> > +#define  WIN_ENABLE_SHIFT    0
> > +#define  WIN_TYPE_SHIFT              1
> > +#define  WIN_SIZE_SHIFT              10
> > +
> > +#define PAB_EXT_AXI_AMAP_SIZE(win)   PAB_REG_ADDR_4(0xbaf0, win)
> > +
> > +#define PAB_AXI_AMAP_AXI_WIN(win)    PAB_REG_ADDR_16(0x0ba4, win)
> > +#define  AXI_WINDOW_BASE_SHIFT               2
> > +
> > +#define PAB_AXI_AMAP_PEX_WIN_L(win)  PAB_REG_ADDR_16(0x0ba8, win)
> > +#define  PAB_BUS_SHIFT                       24
> > +#define  PAB_DEVICE_SHIFT            19
> > +#define  PAB_FUNCTION_SHIFT          16
> > +
> > +#define PAB_AXI_AMAP_PEX_WIN_H(win)  PAB_REG_ADDR_16(0x0bac, win)
> > +#define PAB_INTP_AXI_PIO_CLASS               0x474
>
> This one is a bit odd here, move it up in the file.
>
> > +#define PAB_PEX_AMAP_CTRL(win)               PAB_REG_ADDR_16(0x4ba0, win)
> > +#define  AMAP_CTRL_EN_SHIFT          0
> > +#define  AMAP_CTRL_TYPE_SHIFT                1
> > +
> > +#define PAB_EXT_PEX_AMAP_SIZEN(win)  PAB_REG_ADDR_4(0xbef0, win)
> > +#define PAB_PEX_AMAP_AXI_WIN(win)    PAB_REG_ADDR_16(0x4ba4, win)
> > +#define PAB_PEX_AMAP_PEX_WIN_L(win)  PAB_REG_ADDR_16(0x4ba8, win)
> > +#define PAB_PEX_AMAP_PEX_WIN_H(win)  PAB_REG_ADDR_16(0x4bac, win)
>
> Here you have three base offsets:
>
> 0xb00
> 0x4000
> 0xb000
>
> you can create a macro for each of them, according to what they
> represent and then add an offset into each.
>
> > +
> > +/* supported number of interrupts */
> > +#define PCI_NUM_INTX         4
>
> It is already defined in linux/pci.h
>
> > +#define PAB_INTA_POS         5
> > +
> > +/* outbound and inbound window definitions */
> > +#define WIN_NUM_0            0
> > +#define WIN_NUM_1            1
> > +#define CFG_WINDOW_TYPE              0
> > +#define IO_WINDOW_TYPE               1
> > +#define MEM_WINDOW_TYPE              2
> > +#define IB_WIN_SIZE          (256 * 1024 * 1024)
> > +#define MAX_PIO_WINDOWS              8
> > +
> > +/* Parameters for the waiting for link up routine */
> > +#define LINK_WAIT_MAX_RETRIES        10
> > +#define LINK_WAIT_MIN                90000
> > +#define LINK_WAIT_MAX                100000
> > +
> > +#ifndef UINT64_MAX
> > +#define UINT64_MAX           (u64)(~((u64)0))
> > +#endif
> > +
> > +struct mobiveil_pcie {
> > +     struct platform_device *pdev;
> > +     struct list_head resources;
> > +     void __iomem *config_axi_slave_base;    /* endpoint config base */
> > +     void __iomem *csr_axi_slave_base;       /* root port config base */
> > +     struct irq_domain *intx_domain;
> > +     int irq;
> > +     int apio_wins;
> > +     int ppio_wins;
> > +     int ob_wins_configured; /*  configured outbound windows */
> > +     int ib_wins_configured; /*  configured inbound windows */
> > +     struct resource *ob_io_res;
> > +     char root_bus_nr;
> > +};
> > +
> > +static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
> > +             const u32 reg)
> > +{
> > +     writel_relaxed(value, pcie->csr_axi_slave_base + reg);
> > +}
> > +
> > +static inline u32 csr_readl(struct mobiveil_pcie *pcie,      const u32 reg)
> > +{
> > +     return readl_relaxed(pcie->csr_axi_slave_base + reg);
> > +}
> > +
> > +static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
> > +{
> > +     return (csr_readl(pcie, LTSSM_STATUS) &
> > +             LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
> > +}
>
> https://marc.info/?l=linux-pci&m=151329230814614&w=2
>
> Bjorn would like to remove it.

I do not have a solid explanation for this, as I followed the earlier
driver framework. I'll remove it for now.
>
>
> > +static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
> > +{
> > +     struct mobiveil_pcie *pcie = bus->sysdata;
> > +
> > +     /* Check if link is up when trying to access downstream ports */
> > +     if (bus->number != pcie->root_bus_nr)
> > +             if (!mobiveil_pcie_link_up(pcie))
> > +                     return false;
> > +
> > +     /* Only one device down on each root port */
> > +     if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
> > +             return false;
> > +
> > +     /*
> > +      * Do not read more than one device on the bus directly
> > +      * attached to RC
> > +      */
> > +     if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
> > +             return false;
> > +
> > +     return true;
> > +}
> > +
> > +/*
> > + * mobiveil_pcie_map_bus - routine to get the configuration base of either
> > + * root port or endpoint
> > + */
> > +static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
> > +                                     unsigned int devfn, int where)
> > +{
> > +     struct mobiveil_pcie *pcie = bus->sysdata;
> > +
> > +     if (!mobiveil_pcie_valid_device(bus, devfn))
> > +             return NULL;
> > +
> > +     if (bus->number == pcie->root_bus_nr) {
> > +             /* RC config access */
> > +             return pcie->csr_axi_slave_base + where;
> > +     } else {
> > +             /*
> > +              * EP config access (in Config/APIO space)
> > +              * Program PEX Address base (31..16 bits) with appropriate value
> > +              * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
> > +              * Relies on pci_lock serialization
> > +              */
> > +             csr_writel(pcie,
> > +                     bus->number << PAB_BUS_SHIFT |
> > +                     PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
> > +                     PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
> > +                     PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
> > +             return pcie->config_axi_slave_base + where;
> > +     }
> > +}
> > +
> > +static struct pci_ops mobiveil_pcie_ops = {
> > +     .map_bus = mobiveil_pcie_map_bus,
> > +     .read = pci_generic_config_read,
> > +     .write = pci_generic_config_write,
> > +};
> > +
> > +static void mobiveil_pcie_isr(struct irq_desc *desc)
> > +{
> > +     struct irq_chip *chip = irq_desc_get_chip(desc);
> > +     struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
> > +     struct device *dev = &pcie->pdev->dev;
> > +     u32 intr_status;
> > +     unsigned long shifted_status;
>
> Why not u32 ?
>
for_each_set_bit() api warns about the variable not being unsigned
long. So used the same to take out the warning.


> > +     u32 bit, virq;
> > +     u32 val, mask;
> > +
> > +     chained_irq_enter(chip, desc);
> > +
> > +     /* read INTx status */
> > +     val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> > +     mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> > +     intr_status = val & mask;
> > +
> > +     /*
> Handle INTx */
> > +     if (intr_status & PAB_INTP_INTX_MASK) {
> > +             shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
>
> Why can't you reuse val to read the status and create shifted_status
> from it ?
>
> eg
>
> shifted_status = val << PAB_INTA_POS;
> csr_writel(pcie, shifted_status, PAB_INTP_AMBA_MISC_STAT);
>
> Just a hint to make the loop more readable. BTW, I do not think that
> writing shifted_status into that register is OK, see below.
>
> > +             do {
> > +                     for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
> > +
> > +                             /* clear interrupts */
> > +                             csr_writel(pcie, shifted_status <<
> PAB_INTA_POS,
> > +
> PAB_INTP_AMBA_MISC_STAT);
>
> Should not you clear just the interrupt you are about to handle ?

PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
bits at positions 5,6,7 and 8,
they are RW1C bits, so writing 1 to this bit clears the status.
So here the status read was written back to it to clear.
>
>
> > +                             virq = irq_find_mapping(pcie->intx_domain,
> > +                                     bit + 1);
> > +                             if (virq)
> > +
> generic_handle_irq(virq);
> > +                             else
> > +                                     dev_err_ratelimited(dev,
> > +                                             "unexpected IRQ, INT%d\n",
> > +                                             bit);
> > +
> > +                     }
> > +
> > +                     shifted_status = csr_readl(pcie,
> > +                                             PAB_INTP_AMBA_MISC_STAT);
> > +
> > +             } while ((shifted_status >>  PAB_INTA_POS) != 0);
>
> I do not understand this. Can you explain to me how the
> register at:
>
> PAB_INTP_AMBA_MISC_STAT
>
> works ?
>
just repeating what explained before, to ease the readablility.
PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
bits at positions 5,6,7 and 8,
they are RW1C bits, so writing 1 to this bit clears the status.

>
> A patch for mediatek has been posted:
>
> https://patchwork.ozlabs.org/patch/851181/
>
> It looks like this loop may suffer from the same issue, so please do
> have a look.
>
I will clear the the interrupt after

its hadled by generic_handle_irq()
.
right ?
>
> On top of that, most of the operations you are carrying out here
> can be done automatically by making them part of the struct irq_chip
> methods (ie acking IRQs, masking IRQs, etc, see below).
>
Any side effects of keeping this code as is ?

>
> > +     }
> > +
> > +     csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);
>
> > +     chained_irq_exit(chip, desc);
> > +}
> > +
> > +static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
> > +{
> > +     struct device *dev = &pcie->pdev->dev;
> > +     struct platform_device *pdev = pcie->pdev;
> > +     struct device_node *node = dev->of_node;
> > +     struct resource *res;
> > +     const char *type;
> > +
> > +     type = of_get_property(node, "device_type", NULL);
> > +     if (!type || strcmp(type, "pci")) {
> > +             dev_err(dev, "invalid \"device_type\" %s\n", type);
> > +             return -EINVAL;
> > +     }
> > +
> > +     /* map config resource */
> > +     res = platform_get_resource_byname(pdev,
> > +             IORESOURCE_MEM, "config_axi_slave");
> > +     pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> > +     if (IS_ERR(pcie->config_axi_slave_base))
> > +             return PTR_ERR(pcie->config_axi_slave_base);
> > +     pcie->ob_io_res = res;
> > +
> > +     /* map csr resource */
> > +     res = platform_get_resource_byname(pdev,
> > +             IORESOURCE_MEM, "csr_axi_slave");
> > +     pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> > +     if (IS_ERR(pcie->csr_axi_slave_base))
> > +             return PTR_ERR(pcie->csr_axi_slave_base);
> > +
> > +     /* read the number of windows requested */
> > +     if (!pcie->apio_wins &&
> > +             of_property_read_u32(node, "apio-wins", &pcie->apio_wins)) {
> > +             pcie->apio_wins = MAX_PIO_WINDOWS;
> > +     }
> > +
> > +     if (!pcie->ppio_wins &&
>
> What I wanted to say in my previous review is that apio_wins and
> ppio_wins are zero here why would they be any different and why
> do you need to check that.

Understood. I will remove this redundant check.

>
>
> > +             of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins)) {
> > +             pcie->ppio_wins = MAX_PIO_WINDOWS;
> > +     }
> > +
> > +     pcie->irq = platform_get_irq(pdev, 0);
> > +     if (pcie->irq <= 0) {
> > +             dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
> > +             return -ENODEV;
> > +     }
> > +
> > +     irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
> > +
> > +     return 0;
> > +}
> > +
> > +/*
> > + * select_paged_register - routine to access paged register of root complex
> > + *
> > + * registers of RC are paged, for this scheme to work
> > + * extracted higher 6 bits of the offset will be written to pg_sel
> > + * field of PAB_CTRL register and rest of the lower 10 bits enabled with
> > + * PAGE_SEL_EN are used as offset of the register.
> > + *
> > + */
> > +static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> > +{
> > +     int pab_ctrl_dw, pg_sel;
> > +
> > +     /* clear pg_sel field */
> > +     pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
> > +     pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
> > +
> > +     /* set pg_sel field */
> > +     pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
> > +     pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
> > +     csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
> > +}
> > +
> > +static void write_paged_register(struct mobiveil_pcie *pcie,
> > +             u32 val, u32 offset)
> > +{
> > +     u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> > +
> > +     select_paged_register(pcie, offset);
> > +     csr_writel(pcie, val, off);
> > +}
> > +
> > +static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> > +{
> > +     u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> > +
> > +     select_paged_register(pcie, offset);
> > +     return csr_readl(pcie, off);
> > +}
> > +
> > +static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
> > +             int pci_addr, int type, int size_kb)
> > +{
> > +     int pio_ctrl_val;
> > +     int amap_ctrl_dw;
> > +     u64 size64 = (UINT64_MAX << (WIN_SIZE_SHIFT + ilog2(size_kb)));
> > +
> > +     if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
> > +             dev_err(&pcie->pdev->dev,
> > +                     "ERROR: max inbound windows reached !\n");
> > +             return;
> > +     }
> > +
> > +     pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
> > +     csr_writel(pcie,
> > +             pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
> > +     amap_ctrl_dw =  read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
> > +     amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
> > +     amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
> > +
> > +     write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
> > +                             PAB_PEX_AMAP_CTRL(win_num));
> > +
> > +     write_paged_register(pcie, upper_32_bits(size64),
> > +                             PAB_EXT_PEX_AMAP_SIZEN(win_num));
> > +
> > +     write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
> > +     write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
> > +     write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
> > +}
> > +
> > +static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
> > +             u64 cpu_addr, u64 pci_addr, int config_io_bit,
> > +             int size_kb)
> > +{
> > +
> > +     u32 value, type;
> > +     u64
> size64 = (UINT64_MAX << (WIN_SIZE_SHIFT +
> ilog2(size_kb)));
>
> Can you explain to me the sizing mechanism please ? It is just to make
> sure I got it right.

this register follows the PCI BAR sizing convention.

size64 is actually ~(size-1),
Looks like we can just do that instead of jugglery of bit shifting and ilog2().
>
>
> > +     if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
> > +             dev_err(&pcie->pdev->dev,
> > +                     "ERROR: max outbound windows reached !\n");
> > +             return;
> > +     }
> > +
> > +     /*
> > +      * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
> > +      * to 4 KB in PAB_AXI_AMAP_CTRL register
> > +      */
> > +     type = config_io_bit;
> > +     value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
> > +     csr_writel(pcie,
> > +                     1 << WIN_ENABLE_SHIFT |
> > +                     type << WIN_TYPE_SHIFT |
> > +                     lower_32_bits(size64),
> > +                     PAB_AXI_AMAP_CTRL(win_num));
> > +
> > +     write_paged_register(pcie, upper_32_bits(size64),
> > +                             PAB_EXT_AXI_AMAP_SIZE(win_num));
> > +
> > +     /*
> > +      *
> program
> AXI window base with appropriate value in
> > +      * PAB_AXI_AMAP_AXI_WIN0 register
> > +      */
> > +     value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
> > +     csr_writel(pcie,
> > +                     cpu_addr >> AXI_WINDOW_BASE_SHIFT <<
> > +                     AXI_WINDOW_BASE_SHIFT, PAB_AXI_AMAP_AXI_WIN(win_num));
> > +
> > +     value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));
>
> What's "value" used for in this function ?

My bad, it was used in the previous versions and not cleaned up. I will now.
>
>
>
> > +     csr_writel(pcie, lower_32_bits(pci_addr),
> > +                     PAB_AXI_AMAP_PEX_WIN_L(win_num));
> > +     csr_writel(pcie, upper_32_bits(pci_addr),
> > +                     PAB_AXI_AMAP_PEX_WIN_H(win_num));
> > +
> > +     pcie->ob_wins_configured++;
> > +}
> > +
> > +static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
> > +{
> > +     int retries;
> > +
> > +     /* check if the link is up or not */
> > +     for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
> > +             if (mobiveil_pcie_link_up(pcie))
> > +                     return 0;
> > +
> > +             usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
> > +     }
> > +     dev_err(&pcie->pdev->dev, "link never came up\n");
> > +     return -ETIMEDOUT;
> > +}
> > +
> > +static int
> mobiveil_host_init(struct mobiveil_pcie *pcie)
> > +{
> > +     u32 value;
> > +     int type = 0;
>
> You reinitialize it later and it should not be an int but an unsigned
> type.
>
> > +     u32 pab_ctrl;
> > +     int err;
> > +     struct resource_entry *win, *tmp;
> > +
> > +     /* setup the PCIe slot link power*/
>
> Comment is useless, remove it.
>
> > +     err = mobiveil_bringup_link(pcie);
> > +     if (err) {
> > +             dev_info(&pcie->pdev->dev, "link bring-up failed\n");
> > +             return err;
> > +     }
> > +
> > +     /*
> > +      * program Bus Master Enable Bit in Command Register in PAB Config
> > +      * Space
> > +      */
> > +     value = csr_readl(pcie, PCI_COMMAND);
> > +     csr_writel(pcie,
> > +             value |
>
> Why is this on a separate line ?
>
> > +             PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
> > +             PCI_COMMAND);
> > +
> > +     /*
> > +      * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
> > +      * register
> > +      */
> > +     pab_ctrl = csr_readl(pcie, PAB_CTRL);
> > +     csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
> > +             (1 << PEX_PIO_ENABLE_SHIFT),
> > +             PAB_CTRL);
> > +
> > +     csr_writel(pcie, PAB_INTP_INTX_MASK, PAB_INTP_AMBA_MISC_ENB);
> > +
> > +     /* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
> > +      * PAB_AXI_PIO_CTRL Register
> > +      */
> > +     value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
> > +     csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
> > +
> > +     /*
> > +      * we'll program one outbound window for config reads and
> > +      * another default inbound window for all the upstream traffic
> > +      * rest of the outbound windows will be configured according to
> > +      * the "ranges" field defined in device tree
> > +      */
> > +
> > +     /* config outbound translation window */
> > +     program_ob_windows(pcie, pcie->ob_wins_configured,
> > +                     pcie->ob_io_res->start, 0, CFG_WINDOW_TYPE,
> > +                     resource_size(pcie->ob_io_res)/1024);
> > +
> > +     /* memory inbound  translation window */
> > +     program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
> > +
> > +     /* Get the I/O and memory ranges from DT */
> > +     resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
> > +             type = 0;
> > +             if (resource_type(win->res) == IORESOURCE_MEM)
> > +                     type = MEM_WINDOW_TYPE;
> > +             if (resource_type(win->res) == IORESOURCE_IO)
> > +                     type = IO_WINDOW_TYPE;
> > +             if (type) {
> > +                     /* configure outbound translation window */
> > +                     program_ob_windows(pcie, pcie->ob_wins_configured,
> > +                             win->res->start, 0, type,
> > +                             resource_size(win->res)/1024);
> > +             }
> > +     }
> > +
> > +     return err;
> > +}
> > +
> > +/* routine to setup the INTx related data */
> > +static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > +             irq_hw_number_t hwirq)
> > +{
> > +     irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
>
> IIUC, the host bridge acts as an INTX/MSI controller/multiplexer.
>
> So, instead of relying on
> dummy_irq_chip, you should create your own
> irq_chip with the methods that you require (eg irq_ack(), irq_mask(),
> irq_compose_msi_msg()) and use that as bottom irq_chip for both
> INTX and MSI domains.
>
> That's why I asked you to have a look at pcie-tango.c (except that there
> INTX aren't supported but the basic idea does not change) and implement
> IRQ domains handling like that same driver.
>
are there any disadvantages of keeping dummy_irq_chip, as I see quite
a few host bridge

drivers including
otehr two major soft IP drivers from altera and xilinx with similar
MSI implementaion.
>
> > +     irq_set_chip_data(irq, domain->host_data);
> > +     return 0;
> > +}
> > +
> > +/* INTx domain opeartions structure */
>
> s/opeartions/operations
>
> > +static const struct irq_domain_ops intx_domain_ops = {
> > +     .map = mobiveil_pcie_intx_map,
> > +};
> > +
> > +static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
> > +{
> > +     struct device *dev = &pcie->pdev->dev;
> > +     struct device_node *node = dev->of_node;
> > +     int ret;
>
> ret is unused
>
> > +     /* setup INTx */
> > +     pcie->intx_domain = irq_domain_add_linear(node,
> > +                             PCI_NUM_INTX + 1, &intx_domain_ops, pcie);
>
> You should use PCI_NUM_INTX and add pci_irqd_intx_xlate() as the
> domain ops .xlate.
>
> > +     if (!pcie->intx_domain) {
> > +             dev_err(dev, "Failed to get a INTx IRQ domain\n");
> > +             return -ENODEV;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int mobiveil_pcie_probe(struct platform_device *pdev)
> > +{
> > +     struct mobiveil_pcie *pcie;
> > +     struct pci_bus *bus;
> > +     struct pci_bus *child;
> > +     struct pci_host_bridge *bridge;
> > +     struct device *dev = &pdev->dev;
> > +     struct device_node *node = dev->of_node;
> > +     resource_size_t iobase;
> > +     int ret;
> > +
> > +     /* allocate the PCIe port */
> > +     bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> > +     if (!bridge)
> > +             return -ENODEV;
> > +
> > +     pcie = pci_host_bridge_priv(bridge);
> > +     if (!pcie)
> > +             return -ENOMEM;
> > +
> > +     pcie->pdev = pdev;
> > +
> > +     /* parse the device tree */
>
> Remove this comment, it does not add anything.
>
> > +     ret = mobiveil_pcie_parse_dt(pcie);
> > +     if (ret) {
> > +             dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
> > +             return ret;
> > +     }
> > +
> > +     INIT_LIST_HEAD(&pcie->resources);
> > +
> > +     /* parse the host bridge base addresses from the device tree file */
> > +     ret = of_pci_get_host_bridge_resources(node,
> > +                     0, 0xff, &pcie->resources, &iobase);
> > +     if (ret) {
> > +             dev_err(dev, "Getting bridge resources failed\n");
> > +             return -ENOMEM;
> > +     }
> > +
> > +     /*
> > +      * configure all inbound and outbound windows and prepare the RC for
> > +      * config access
> > +      */
> > +     ret = mobiveil_host_init(pcie);
> > +     if (ret) {
> > +             dev_err(dev, "Failed to initialize host\n");
> > +             goto error;
> > +     }
> > +
> > +     /* fixup for PCIe class register */
> > +     csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
> > +
> > +     /* initialize the IRQ domains */
> > +     ret = mobiveil_pcie_init_irq_domain(pcie);
> > +     if (ret) {
> > +             dev_err(dev, "Failed creating IRQ Domain\n");
> > +             goto error;
> > +     }
> > +
> > +
>
> Two empty lines, should be one.
>
> > +     ret = devm_request_pci_bus_resources(dev, &pcie->resources);
> > +     if (ret)
> > +             goto error;
> > +
> > +     /* Initialize bridge */
> > +     list_splice_init(&pcie->resources, &bridge->windows);
> > +     bridge->dev.parent = dev;
> > +     bridge->sysdata = pcie;
> > +     bridge->busnr = pcie->root_bus_nr;
> > +     bridge->ops = &mobiveil_pcie_ops;
> > +     bridge->map_irq = of_irq_parse_and_map_pci;
> > +     bridge->swizzle_irq = pci_common_swizzle;
> > +
> > +     /* setup the kernel resources for the newly added PCIe root bus */
> > +     ret = pci_scan_root_bus_bridge(bridge);
> > +     if (ret)
> > +             goto error;
> > +
> > +     bus = bridge->bus;
> > +
> > +     pci_assign_unassigned_bus_resources(bus);
> > +     list_for_each_entry(child, &bus->children, node)
> > +             pcie_bus_configure_settings(child);
> > +     pci_bus_add_devices(bus);
> > +
> > +     platform_set_drvdata(pdev, pcie);
>
> Is this really needed ?
>
> Thanks,
> Lorenzo
>
> > +
> > +     return 0;
> > +error:
> > +     pci_free_resource_list(&pcie->resources);
> > +     return ret;
> > +}
> > +
> > +static const struct of_device_id mobiveil_pcie_of_match[] = {
> > +     {.compatible = "mbvl,gpex40-pcie",},
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
> > +
> > +static struct platform_driver mobiveil_pcie_driver = {
> > +     .probe = mobiveil_pcie_probe,
> > +     .driver = {
> > +                     .name = "mobiveil-pcie",
> > +                     .of_match_table = mobiveil_pcie_of_match,
> > +                     .suppress_bind_attrs = true,
> > +             },
> > +};
> > +
> > +builtin_platform_driver(mobiveil_pcie_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
> > +MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>");
> > --
> > 1.8.3.1
> >


Thanks,
Subrahmanya

Re: [PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Lorenzo Pieralisi]

On Fri, Dec 22, 2017 at 01:29:00PM +0530, Subrahmanya Lingappa wrote:

[...]

> > > +static void mobiveil_pcie_isr(struct irq_desc *desc)
> > > +{
> > > +     struct irq_chip *chip = irq_desc_get_chip(desc);
> > > +     struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
> > > +     struct device *dev = &pcie->pdev->dev;
> > > +     u32 intr_status;
> > > +     unsigned long shifted_status;
> >
> > Why not u32 ?
> >
> for_each_set_bit() api warns about the variable not being unsigned
> long. So used the same to take out the warning.
> 
> 
> > > +     u32 bit, virq;
> > > +     u32 val, mask;
> > > +
> > > +     chained_irq_enter(chip, desc);
> > > +
> > > +     /* read INTx status */
> > > +     val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> > > +     mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> > > +     intr_status = val & mask;
> > > +
> > > +     /*
> > Handle INTx */
> > > +     if (intr_status & PAB_INTP_INTX_MASK) {
> > > +             shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> >
> > Why can't you reuse val to read the status and create shifted_status
> > from it ?
> >
> > eg
> >
> > shifted_status = val << PAB_INTA_POS;
> > csr_writel(pcie, shifted_status, PAB_INTP_AMBA_MISC_STAT);
> >
> > Just a hint to make the loop more readable. BTW, I do not think that
> > writing shifted_status into that register is OK, see below.
> >
> > > +             do {
> > > +                     for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
> > > +
> > > +                             /* clear interrupts */
> > > +                             csr_writel(pcie, shifted_status <<
> > PAB_INTA_POS,
> > > +
> > PAB_INTP_AMBA_MISC_STAT);
> >
> > Should not you clear just the interrupt you are about to handle ?
> 
> PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
> bits at positions 5,6,7 and 8,
> they are RW1C bits, so writing 1 to this bit clears the status.
> So here the status read was written back to it to clear.

Understood - the point is that IIUC you should clear just the IRQ (bit)
that you are handling at each iteration not all at once.

What do PAB_INTP_AMBA_MISC_STAT[4:0] represent then ?

> > > +                             virq = irq_find_mapping(pcie->intx_domain,
> > > +                                     bit + 1);
> > > +                             if (virq)
> > > +
> > generic_handle_irq(virq);
> > > +                             else
> > > +                                     dev_err_ratelimited(dev,
> > > +                                             "unexpected IRQ, INT%d\n",
> > > +                                             bit);
> > > +
> > > +                     }
> > > +
> > > +                     shifted_status = csr_readl(pcie,
> > > +                                             PAB_INTP_AMBA_MISC_STAT);
> > > +
> > > +             } while ((shifted_status >>  PAB_INTA_POS) != 0);
> >
> > I do not understand this. Can you explain to me how the
> > register at:
> >
> > PAB_INTP_AMBA_MISC_STAT
> >
> > works ?
> >
> just repeating what explained before, to ease the readablility.
> PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
> bits at positions 5,6,7 and 8,
> they are RW1C bits, so writing 1 to this bit clears the status.
> 
> >
> > A patch for mediatek has been posted:
> >
> > https://patchwork.ozlabs.org/patch/851181/
> >
> > It looks like this loop may suffer from the same issue, so please do
> > have a look.
> >
> I will clear the the interrupt after
> 
> its hadled by generic_handle_irq()
> .
> right ?

Where ? Can you explain please what every bit in

PAB_INTP_AMBA_MISC_STAT

represent ?

> > On top of that, most of the operations you are carrying out here
> > can be done automatically by making them part of the struct irq_chip
> > methods (ie acking IRQs, masking IRQs, etc, see below).
> >
> Any side effects of keeping this code as is ?

Yes, that it will take us more effort to convert it to the usage
I describe above - which is how it is expected to be written.

[...]

> > > +/* routine to setup the INTx related data */
> > > +static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > > +             irq_hw_number_t hwirq)
> > > +{
> > > +     irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> >
> > IIUC, the host bridge acts as an INTX/MSI controller/multiplexer.
> >
> > So, instead of relying on
> > dummy_irq_chip, you should create your own
> > irq_chip with the methods that you require (eg irq_ack(), irq_mask(),
> > irq_compose_msi_msg()) and use that as bottom irq_chip for both
> > INTX and MSI domains.
> >
> > That's why I asked you to have a look at pcie-tango.c (except that there
> > INTX aren't supported but the basic idea does not change) and implement
> > IRQ domains handling like that same driver.
> >
> are there any disadvantages of keeping dummy_irq_chip, as I see quite
> a few host bridge
> 
> drivers including
> otehr two major soft IP drivers from altera and xilinx with similar
> MSI implementaion.

See above, this is a new driver, the existing IP drivers will have to
be converted eventually, new code should set an example not add more
burden to code refactoring.

Lorenzo

Re: [PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Subrahmanya Lingappa]

Lorenzo,

On Tue, Jan 2, 2018 at 7:43 PM, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Fri, Dec 22, 2017 at 01:29:00PM +0530, Subrahmanya Lingappa wrote:
>
> [...]
>
> > > > +static void mobiveil_pcie_isr(struct irq_desc *desc)
> > > > +{
> > > > +     struct irq_chip *chip = irq_desc_get_chip(desc);
> > > > +     struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
> > > > +     struct device *dev = &pcie->pdev->dev;
> > > > +     u32 intr_status;
> > > > +     unsigned long shifted_status;
> > >
> > > Why not u32 ?
> > >
> > for_each_set_bit() api warns about the variable not being unsigned
> > long. So used the same to take out the warning.
> >
> >
> > > > +     u32 bit, virq;
> > > > +     u32 val, mask;
> > > > +
> > > > +     chained_irq_enter(chip, desc);
> > > > +
> > > > +     /* read INTx status */
> > > > +     val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> > > > +     mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> > > > +     intr_status = val & mask;
> > > > +
> > > > +     /*
> > > Handle INTx */
> > > > +     if (intr_status & PAB_INTP_INTX_MASK) {
> > > > +             shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> > >
> > > Why can't you reuse val to read the status and create shifted_status
> > > from it ?
> > >
> > > eg
> > >
> > > shifted_status = val << PAB_INTA_POS;
> > > csr_writel(pcie, shifted_status, PAB_INTP_AMBA_MISC_STAT);
> > >
> > > Just a hint to make the loop more readable. BTW, I do not think that
> > > writing shifted_status into that register is OK, see below.
> > >
> > > > +             do {
> > > > +                     for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
> > > > +
> > > > +                             /* clear interrupts */
> > > > +                             csr_writel(pcie, shifted_status <<
> > > PAB_INTA_POS,
> > > > +
> > > PAB_INTP_AMBA_MISC_STAT);
> > >
> > > Should not you clear just the interrupt you are about to handle ?
> >
> > PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
> > bits at positions 5,6,7 and 8,
> > they are RW1C bits, so writing 1 to this bit clears the status.
> > So here the status read was written back to it to clear.
>
> Understood - the point is that IIUC you should clear just the IRQ (bit)
> that you are handling at each iteration not all at once.
>
Understood

>
> What do PAB_INTP_AMBA_MISC_STAT[4:0] represent then ?

0 : PCIE to AXI Mailbox Ready
This bit is set by hardware when a PCIE-to-AXI mailbox is ready with
data to be transferred to PCI-Express host.
1 : Reserved
2 : Reserved
3 : Reserved
4 : Vendor Defined Message Received
This bit is set by hardware when an vendor defined message is
received on the PEX link.

5 : INTA Received
6 : INTB Received
7 : INTC Received
8 : INTD Received
9-31: Other
root port
error status bits
>
>
> > > > +                             virq = irq_find_mapping(pcie->intx_domain,
> > > > +                                     bit + 1);
> > > > +                             if (virq)
> > > > +
> > > generic_handle_irq(virq);
> > > > +                             else
> > > > +                                     dev_err_ratelimited(dev,
> > > > +                                             "unexpected IRQ, INT%d\n",
> > > > +                                             bit);
> > > > +
> > > > +                     }
> > > > +
> > > > +                     shifted_status = csr_readl(pcie,
> > > > +                                             PAB_INTP_AMBA_MISC_STAT);
> > > > +
> > > > +             } while ((shifted_status >>  PAB_INTA_POS) != 0);
> > >
> > > I do not understand this. Can you explain to me how the
> > > register at:
> > >
> > > PAB_INTP_AMBA_MISC_STAT
> > >
> > > works ?
> > >
> > just repeating what explained before, to ease the readablility.
> > PAB_INTP_AMBA_MISC_STAT register has INTA, INTB, INTC, INTD status
> > bits at positions 5,6,7 and 8,
> > they are RW1C bits, so writing 1 to this bit clears the status.
> >
> > >
> > > A patch for mediatek has been posted:
> > >
> > > https://patchwork.ozlabs.org/patch/851181/
> > >
> > > It looks like this loop may suffer from the same issue, so please do
> > > have a look.
> > >
> > I will clear the the interrupt after
> >
> > its hadled by generic_handle_irq()
> > .
> > right ?
>
> Where ? Can you explain please what every bit in
>
> PAB_INTP_AMBA_MISC_STAT
>
> represent ?
>
Please see the list above


> > > On top of that, most of the operations you are carrying out here
> > > can be done automatically by making them part of the struct irq_chip
> > > methods (ie acking IRQs, masking IRQs, etc, see below).
> > >
> > Any side effects of keeping this code as is ?
>
> Yes, that it will take us more effort to convert it to the usage
> I describe above - which is how it is expected to be written.
>
Ok, I'll convert this by making these operations as part of

irq_chip methods
>
> [...]
>
> > > > +/* routine to setup the INTx related data */
> > > > +static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > > > +             irq_hw_number_t hwirq)
> > > > +{
> > > > +     irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> > >
> > > IIUC, the host bridge acts as an INTX/MSI controller/multiplexer.
> > >
> > > So, instead of relying on
> > > dummy_irq_chip, you should create your own
> > > irq_chip with the methods that you require (eg irq_ack(), irq_mask(),
> > > irq_compose_msi_msg()) and use that as bottom irq_chip for both
> > > INTX and MSI domains.
> > >
> > > That's why I asked you to have a look at pcie-tango.c (except that there
> > > INTX aren't supported but the basic idea does not change) and implement
> > > IRQ domains handling like that same driver.
> > >
> > are there any disadvantages of keeping dummy_irq_chip, as I see quite
> > a few host bridge
> >
> > drivers including
> > otehr two major soft IP drivers from altera and xilinx with similar
> > MSI implementaion.
>
> See above, this is a new driver, the existing IP drivers will have to
> be converted eventually, new code should set an example not add more
> burden to code refactoring.
>
Agreed, I will follow the tango driver approach to remove dummy_irq_chip.
>
> Lorenzo



Thanks,
Subrahmanya

Re: [PATCH v5 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Lorenzo Pieralisi]

On Wed, Dec 20, 2017 at 05:03:07PM +0000, Lorenzo Pieralisi wrote:

[...]

> > +static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
> > +{
> > +	struct device *dev = &pcie->pdev->dev;
> > +	struct device_node *node = dev->of_node;
> > +	int ret;
> 
> ret is unused
> 
> > +	/* setup INTx */
> > +	pcie->intx_domain = irq_domain_add_linear(node,
> > +				PCI_NUM_INTX + 1, &intx_domain_ops, pcie);
> 
> You should use PCI_NUM_INTX and add pci_irqd_intx_xlate() as the
> domain ops .xlate.

Actually that's not quite correct - so scrap this. The point here is,
the PCI host controller interrupt domain has to have 4 hwirqs (this
is a pseudo interrupt controller - a multiplexer) and it
is through DT interrupt-map that INTx pins (1-4) can be mapped to the
"PCI interrupt controller hwirq inputs" that we consider numbered
from 0 to 3.

It is not that clean-cut but IMO it is the DT interrupt mapping that
should carry out the translation.

See for instance:

arch/arm64/boot/dts/marvell/armada-37xx.dtsi

This requires DT/irqchip maintainers acknowledgement before proceeding.

Lorenzo
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