Message-ID: <1447806715-30043-5-git-send-email-rjui@broadcom.com>
Date:	Tue, 17 Nov 2015 16:31:54 -0800
From:	Ray Jui <rjui@...adcom.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
CC:	Marc Zyngier <marc.zyngier@....com>, Arnd Bergmann <arnd@...db.de>,
	Hauke Mehrtens <hauke@...ke-m.de>,
	<linux-kernel@...r.kernel.org>,
	<bcm-kernel-feedback-list@...adcom.com>,
	<linux-pci@...r.kernel.org>, Ray Jui <rjui@...adcom.com>
Subject: [PATCH 4/5] PCI: iproc: Add iProc PCIe MSI support

This patch adds PCIe MSI support for both PAXB and PAXC interfaces on
all iProc based platforms. The patch follows the latest trend in the
kernel to use MSI domain based implementation

This iProc event queue based MSI support should not be used with newer
platforms with integrated MSI support in the GIC (e.g., giv2m or
gicv3-its)

Signed-off-by: Ray Jui <rjui@...adcom.com>
Reviewed-by: Anup Patel <anup.patel@...adcom.com>
Reviewed-by: Vikram Prakash <vikramp@...adcom.com>
Reviewed-by: Scott Branden <sbranden@...adcom.com>
---
 drivers/pci/host/Kconfig          |   9 +
 drivers/pci/host/Makefile         |   1 +
 drivers/pci/host/pcie-iproc-msi.c | 434 ++++++++++++++++++++++++++++++++++++++
 drivers/pci/host/pcie-iproc.c     |  19 ++
 drivers/pci/host/pcie-iproc.h     |  12 ++
 5 files changed, 475 insertions(+)
 create mode 100644 drivers/pci/host/pcie-iproc-msi.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index f131ba9..972e906 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -126,6 +126,15 @@ config PCIE_IPROC
 	  iProc family of SoCs. An appropriate bus interface driver also needs
 	  to be enabled
 
+config PCIE_IPROC_MSI
+	bool "Broadcom iProc PCIe MSI support"
+	depends on ARCH_BCM_IPROC && PCI_MSI
+	select PCI_MSI_IRQ_DOMAIN
+	default ARCH_BCM_IPROC
+	help
+	  Say Y here if you want to enable MSI support for Broadcom's iProc
+	  PCIe controller
+
 config PCIE_IPROC_PLATFORM
 	tristate "Broadcom iProc PCIe platform bus driver"
 	depends on ARCH_BCM_IPROC || (ARM && COMPILE_TEST)
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 9d4d3c6..0e4e95e 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
 obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
 obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
 obj-$(CONFIG_PCIE_IPROC) += pcie-iproc.o
+obj-$(CONFIG_PCIE_IPROC_MSI) += pcie-iproc-msi.o
 obj-$(CONFIG_PCIE_IPROC_PLATFORM) += pcie-iproc-platform.o
 obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
 obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
diff --git a/drivers/pci/host/pcie-iproc-msi.c b/drivers/pci/host/pcie-iproc-msi.c
new file mode 100644
index 0000000..a55c707
--- /dev/null
+++ b/drivers/pci/host/pcie-iproc-msi.c
@@ -0,0 +1,434 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+
+#include "pcie-iproc.h"
+
+#define IPROC_MSI_INTS_EN_OFFSET       0x208
+#define IPROC_MSI_INTR_EN_SHIFT        11
+#define IPROC_MSI_INTR_EN              BIT(IPROC_MSI_INTR_EN_SHIFT)
+#define IPROC_MSI_INT_N_EVENT_SHIFT    1
+#define IPROC_MSI_INT_N_EVENT          BIT(IPROC_MSI_INT_N_EVENT_SHIFT)
+#define IPROC_MSI_EQ_EN_SHIFT          0
+#define IPROC_MSI_EQ_EN                BIT(IPROC_MSI_EQ_EN_SHIFT)
+
+#define IPROC_MSI_EQ_MASK              0x3f
+
+/* number of queues in each event queue */
+#define IPROC_MSI_EQ_LEN               64
+
+/* size of each event queue memory region */
+#define EQ_MEM_REGION_SIZE           SZ_4K
+
+/* size of each MSI message memory region */
+#define MSI_MSG_MEM_REGION_SIZE      SZ_4K
+
+enum iproc_msi_reg {
+	IPROC_MSI_EQ_PAGE = 0,
+	IPROC_MSI_EQ_PAGE_UPPER,
+	IPROC_MSI_PAGE,
+	IPROC_MSI_PAGE_UPPER,
+	IPROC_MSI_CTRL,
+	IPROC_MSI_EQ_HEAD,
+	IPROC_MSI_EQ_TAIL,
+	IPROC_MSI_REG_SIZE,
+};
+
+/**
+ * iProc event queue based MSI
+ *
+ * Only meant to be used on platforms without MSI support integrated into the
+ * GIC
+ *
+ * @pcie: pointer to iProc PCIe data
+ * @reg_offsets: MSI register offsets
+ * @irqs: pointer to an array that contains the interrupt IDs
+ * @nirqs: number of total interrupts
+ * @has_inten_reg: indicates the MSI interrupt enable register needs to be
+ * set explicitly (required for some legacy platforms)
+ * @used: bitmap to track usage of MSI
+ * @inner_domain: inner IRQ domain
+ * @msi_domain: MSI IRQ domain
+ * @bitmap_lock: lock to protect access to the IRQ bitmap
+ * @n_eq_region: required number of 4K aligned memory region for MSI event
+ * queues
+ * @n_msi_msg_region: required number of 4K aligned memory region for MSI
+ * posted writes
+ * @eq_base: pointer to allocated memory region for MSI event queues
+ * @msi_base: pointer to allocated memory region for MSI posted writes
+ */
+struct iproc_msi {
+	struct iproc_pcie *pcie;
+	const u16 (*reg_offsets)[IPROC_MSI_REG_SIZE];
+	int *irqs;
+	int nirqs;
+	bool has_inten_reg;
+	DECLARE_BITMAP(used, IPROC_PCIE_MAX_NUM_IRQS);
+	struct irq_domain *inner_domain;
+	struct irq_domain *msi_domain;
+	struct mutex bitmap_lock;
+	unsigned int n_eq_region;
+	unsigned int n_msi_msg_region;
+	void *eq_base;
+	void *msi_base;
+};
+
+static const u16
+iproc_msi_reg_paxb[IPROC_PCIE_MAX_NUM_IRQS][IPROC_MSI_REG_SIZE] = {
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x210, 0x250, 0x254 },
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x214, 0x258, 0x25c },
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x218, 0x260, 0x264 },
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x21c, 0x268, 0x26c },
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x220, 0x270, 0x274 },
+	{ 0x200, 0x2c0, 0x204, 0x2c4, 0x224, 0x278, 0x27c },
+};
+
+static const u16
+iproc_msi_reg_paxc[IPROC_PCIE_MAX_NUM_IRQS][IPROC_MSI_REG_SIZE] = {
+	{ 0xc00, 0xc04, 0xc08, 0xc0c, 0xc40, 0xc50, 0xc60 },
+	{ 0xc10, 0xc14, 0xc18, 0xc1c, 0xc44, 0xc54, 0xc64 },
+	{ 0xc20, 0xc24, 0xc28, 0xc2c, 0xc48, 0xc58, 0xc68 },
+	{ 0xc30, 0xc34, 0xc38, 0xc3c, 0xc4c, 0xc5c, 0xc6c },
+};
+
+static inline u32 iproc_msi_read_reg(struct iproc_msi *msi,
+				     enum iproc_msi_reg reg,
+				     unsigned int eq)
+{
+	struct iproc_pcie *pcie = msi->pcie;
+
+	return readl(pcie->base + msi->reg_offsets[eq][reg]);
+}
+
+static inline void iproc_msi_write_reg(struct iproc_msi *msi,
+				       enum iproc_msi_reg reg,
+				       int eq, u32 val)
+{
+	struct iproc_pcie *pcie = msi->pcie;
+
+	writel(val, pcie->base + msi->reg_offsets[eq][reg]);
+}
+
+static struct irq_chip iproc_msi_top_irq_chip = {
+	.name = "iProc MSI",
+	.irq_enable = pci_msi_unmask_irq,
+	.irq_disable = pci_msi_mask_irq,
+	.irq_mask = pci_msi_mask_irq,
+	.irq_unmask = pci_msi_unmask_irq,
+};
+
+static struct msi_domain_info iproc_msi_domain_info = {
+	.flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		MSI_FLAG_PCI_MSIX,
+	.chip = &iproc_msi_top_irq_chip,
+};
+
+static int iproc_msi_irq_set_affinity(struct irq_data *data,
+				      const struct cpumask *mask, bool force)
+{
+	return -EINVAL;
+}
+
+static void iproc_msi_irq_compose_msi_msg(struct irq_data *data,
+					  struct msi_msg *msg)
+{
+	struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
+	phys_addr_t addr;
+
+	addr = virt_to_phys(msi->msi_base) | (data->hwirq * 4);
+	msg->address_lo = lower_32_bits(addr);
+	msg->address_hi = upper_32_bits(addr);
+	msg->data = data->hwirq;
+}
+
+static struct irq_chip iproc_msi_bottom_irq_chip = {
+	.name = "MSI",
+	.irq_set_affinity = iproc_msi_irq_set_affinity,
+	.irq_compose_msi_msg = iproc_msi_irq_compose_msi_msg,
+};
+
+static int iproc_msi_irq_domain_alloc(struct irq_domain *domain,
+				      unsigned int virq, unsigned int nr_irqs,
+				      void *args)
+{
+	struct iproc_msi *msi = domain->host_data;
+	int i, msi_irq;
+
+	mutex_lock(&msi->bitmap_lock);
+
+	for (i = 0; i < nr_irqs; i++) {
+		msi_irq = find_first_zero_bit(msi->used, msi->nirqs);
+		if (msi_irq < msi->nirqs) {
+			set_bit(msi_irq, msi->used);
+		} else {
+			mutex_unlock(&msi->bitmap_lock);
+			return -ENOSPC;
+		}
+
+		irq_domain_set_info(domain, virq + i, msi_irq,
+				    &iproc_msi_bottom_irq_chip,
+				    domain->host_data, handle_simple_irq,
+				    NULL, NULL);
+	}
+
+	mutex_unlock(&msi->bitmap_lock);
+	return 0;
+}
+
+static void iproc_msi_irq_domain_free(struct irq_domain *domain,
+				      unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *data = irq_domain_get_irq_data(domain, virq);
+	struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
+	unsigned int i;
+
+	mutex_lock(&msi->bitmap_lock);
+
+	for (i = 0; i < nr_irqs; i++) {
+		struct irq_data *data = irq_domain_get_irq_data(domain,
+								virq + i);
+		if (!test_bit(data->hwirq, msi->used)) {
+			dev_warn(msi->pcie->dev, "freeing unused MSI %lu\n",
+				 data->hwirq);
+		} else
+			clear_bit(data->hwirq, msi->used);
+	}
+
+	mutex_unlock(&msi->bitmap_lock);
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops msi_domain_ops = {
+	.alloc = iproc_msi_irq_domain_alloc,
+	.free = iproc_msi_irq_domain_free,
+};
+
+static void iproc_msi_enable(struct iproc_msi *msi)
+{
+	struct iproc_pcie *pcie = msi->pcie;
+	int i, eq;
+	u32 val;
+
+	/* program memory region for each event queue */
+	for (i = 0; i < msi->n_eq_region; i++) {
+		phys_addr_t addr =
+			virt_to_phys(msi->eq_base + (i * EQ_MEM_REGION_SIZE));
+
+		iproc_msi_write_reg(msi, IPROC_MSI_EQ_PAGE, i,
+				    lower_32_bits(addr));
+		iproc_msi_write_reg(msi, IPROC_MSI_EQ_PAGE_UPPER, i,
+				    upper_32_bits(addr));
+	}
+
+	/* program memory region for MSI posted writes */
+	for (i = 0; i < msi->n_msi_msg_region; i++) {
+		phys_addr_t addr =
+			virt_to_phys(msi->msi_base +
+				     (i * MSI_MSG_MEM_REGION_SIZE));
+
+		iproc_msi_write_reg(msi, IPROC_MSI_PAGE, i,
+				    lower_32_bits(addr));
+		iproc_msi_write_reg(msi, IPROC_MSI_PAGE_UPPER, i,
+				    upper_32_bits(addr));
+	}
+
+	for (eq = 0; eq < msi->nirqs; eq++) {
+		/* enable MSI event queue */
+		val = IPROC_MSI_INTR_EN | IPROC_MSI_INT_N_EVENT |
+			IPROC_MSI_EQ_EN;
+		iproc_msi_write_reg(msi, IPROC_MSI_CTRL, eq, val);
+
+		/*
+		 * Some legacy platforms require the MSI interrupt enable
+		 * register to be set explicitly
+		 */
+		if (msi->has_inten_reg) {
+			val = readl(pcie->base + IPROC_MSI_INTS_EN_OFFSET);
+			val |= BIT(eq);
+			writel(val, pcie->base + IPROC_MSI_INTS_EN_OFFSET);
+		}
+	}
+}
+
+static void iproc_msi_handler(struct irq_desc *desc)
+{
+	unsigned int irq = irq_desc_get_irq(desc);
+	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	struct iproc_msi *msi;
+	struct iproc_pcie *pcie;
+	u32 eq, head, tail, num_events;
+	int virq;
+
+	chained_irq_enter(irq_chip, desc);
+
+	msi = irq_get_handler_data(irq);
+	pcie = msi->pcie;
+
+	eq = irq - msi->irqs[0];
+	virq = irq_find_mapping(msi->inner_domain, eq);
+	head = iproc_msi_read_reg(msi, IPROC_MSI_EQ_HEAD, eq) &
+		IPROC_MSI_EQ_MASK;
+	do {
+		tail = iproc_msi_read_reg(msi, IPROC_MSI_EQ_TAIL, eq) &
+			IPROC_MSI_EQ_MASK;
+
+		num_events = (tail < head) ?
+			(IPROC_MSI_EQ_LEN - (head - tail)) : (tail - head);
+		if (!num_events)
+			break;
+
+		generic_handle_irq(virq);
+
+		head++;
+		head %= IPROC_MSI_EQ_LEN;
+		iproc_msi_write_reg(msi, IPROC_MSI_EQ_HEAD, eq, head);
+	} while (true);
+
+	chained_irq_exit(irq_chip, desc);
+}
+
+int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node)
+{
+	struct iproc_msi *msi;
+	struct device_node *parent_node;
+	struct irq_domain *parent_domain;
+	int i, ret;
+
+	if (!of_device_is_compatible(node, "brcm,iproc-msi"))
+		return -ENODEV;
+
+	if (!of_find_property(node, "msi-controller", NULL))
+		return -ENODEV;
+
+	parent_node = of_parse_phandle(node, "interrupt-parent", 0);
+	if (!parent_node) {
+		dev_err(pcie->dev, "unable to parse MSI interrupt parent\n");
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent_node);
+	if (!parent_domain) {
+		dev_err(pcie->dev, "unable to get MSI parent domain\n");
+		return -ENODEV;
+	}
+
+	msi = devm_kzalloc(pcie->dev, sizeof(*msi), GFP_KERNEL);
+	if (!msi)
+		return -ENOMEM;
+
+	msi->pcie = pcie;
+	mutex_init(&msi->bitmap_lock);
+
+	switch (pcie->type) {
+	case IPROC_PCIE_PAXB:
+		msi->reg_offsets = iproc_msi_reg_paxb;
+		break;
+	case IPROC_PCIE_PAXC:
+		msi->reg_offsets = iproc_msi_reg_paxc;
+		break;
+	default:
+		dev_err(pcie->dev, "incompatible iProc PCIe interface\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32(node, "brcm,num-eq-region",
+				   &msi->n_eq_region);
+	if (ret || msi->n_eq_region == 0) {
+		dev_err(pcie->dev,
+			"invalid property 'brcm,num-eq-region' %u\n",
+			msi->n_eq_region);
+		return -ENODEV;
+	}
+
+	ret = of_property_read_u32(node, "brcm,num-msi-msg-region",
+				   &msi->n_msi_msg_region);
+	if (ret || msi->n_msi_msg_region == 0) {
+		dev_err(pcie->dev,
+			"invalid property 'brcm,num-msi-msg-region' %u\n",
+			msi->n_msi_msg_region);
+		return -ENODEV;
+	}
+
+	/* reserve memory for MSI event queue */
+	msi->eq_base = devm_kcalloc(pcie->dev, msi->n_eq_region + 1,
+				    EQ_MEM_REGION_SIZE, GFP_KERNEL);
+	if (!msi->eq_base)
+		return -ENOMEM;
+	msi->eq_base = PTR_ALIGN(msi->eq_base, EQ_MEM_REGION_SIZE);
+
+	/* reserve memory for MSI posted writes */
+	msi->msi_base = devm_kcalloc(pcie->dev, msi->n_msi_msg_region + 1,
+				     MSI_MSG_MEM_REGION_SIZE, GFP_KERNEL);
+	if (!msi->msi_base)
+		return -ENOMEM;
+	msi->msi_base = PTR_ALIGN(msi->msi_base, MSI_MSG_MEM_REGION_SIZE);
+
+	if (of_find_property(node, "brcm,pcie-msi-inten", NULL))
+		msi->has_inten_reg = true;
+
+	msi->nirqs = of_irq_count(node);
+	if (!msi->nirqs) {
+		dev_err(pcie->dev, "found no MSI interrupt in DT\n");
+		return -ENODEV;
+	}
+	if (msi->nirqs > IPROC_PCIE_MAX_NUM_IRQS) {
+		dev_warn(pcie->dev, "too many MSI interrupts defined %d\n",
+			 msi->nirqs);
+		msi->nirqs = IPROC_PCIE_MAX_NUM_IRQS;
+	}
+	msi->irqs = devm_kcalloc(pcie->dev, msi->nirqs, sizeof(*msi->irqs),
+				 GFP_KERNEL);
+	if (!msi->irqs)
+		return -ENOMEM;
+
+	for (i = 0; i < msi->nirqs; i++) {
+		msi->irqs[i] = irq_of_parse_and_map(node, i);
+		if (!msi->irqs[i]) {
+			dev_err(pcie->dev, "unable to parse/map interrupt\n");
+			return -ENODEV;
+		}
+	}
+
+	msi->inner_domain = irq_domain_add_hierarchy(parent_domain, 0,
+						     msi->nirqs, NULL,
+						     &msi_domain_ops,
+						     msi);
+	if (!msi->inner_domain) {
+		dev_err(pcie->dev, "failed to create inner domain\n");
+		return -ENOMEM;
+	}
+
+	msi->msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(node),
+						    &iproc_msi_domain_info,
+						    msi->inner_domain);
+	if (!msi->msi_domain) {
+		dev_err(pcie->dev, "failed to create MSI domain\n");
+		irq_domain_remove(msi->inner_domain);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < msi->nirqs; i++)
+		irq_set_chained_handler_and_data(msi->irqs[i],
+						 iproc_msi_handler, msi);
+
+	iproc_msi_enable(msi);
+
+	return 0;
+}
+EXPORT_SYMBOL(iproc_msi_init);
diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
index 24d5b62..a575ef3 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -440,6 +440,21 @@ static int iproc_pcie_map_ranges(struct iproc_pcie *pcie,
 	return 0;
 }
 
+static int iproc_pcie_msi_enable(struct iproc_pcie *pcie)
+{
+	struct device_node *msi_node;
+
+	msi_node = of_parse_phandle(pcie->dev->of_node, "msi-parent", 0);
+	if (!msi_node)
+		return -ENODEV;
+
+	/*
+	 * If another MSI controller is being used, the call below should fail
+	 * but that is okay
+	 */
+	return iproc_msi_init(pcie, msi_node);
+}
+
 int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
 {
 	int ret;
@@ -507,6 +522,10 @@ int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
 
 	iproc_pcie_enable(pcie);
 
+	if (IS_ENABLED(CONFIG_PCI_MSI))
+		if (iproc_pcie_msi_enable(pcie))
+			dev_info(pcie->dev, "not using iProc MSI\n");
+
 	pci_scan_child_bus(bus);
 	pci_assign_unassigned_bus_resources(bus);
 	pci_fixup_irqs(pci_common_swizzle, pcie->map_irq);
diff --git a/drivers/pci/host/pcie-iproc.h b/drivers/pci/host/pcie-iproc.h
index 051b651..17317ef 100644
--- a/drivers/pci/host/pcie-iproc.h
+++ b/drivers/pci/host/pcie-iproc.h
@@ -14,6 +14,8 @@
 #ifndef _PCIE_IPROC_H
 #define _PCIE_IPROC_H
 
+#define IPROC_PCIE_MAX_NUM_IRQS 6
+
 /**
  * iProc PCIe interface type
  *
@@ -74,4 +76,14 @@ struct iproc_pcie {
 int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res);
 int iproc_pcie_remove(struct iproc_pcie *pcie);
 
+#ifdef CONFIG_PCI_MSI
+int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node);
+#else
+static inline int iproc_msi_init(struct iproc_pcie *pcie,
+				 struct device_node *node)
+{
+	return -ENODEV;
+}
+#endif
+
 #endif /* _PCIE_IPROC_H */
-- 
1.9.1

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