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Subject[PATCH 4/6] pci: altera: Add Altera PCIe MSI driver
Date
This patch adds Altera PCIe MSI driver. This soft IP supports configurable
number of vectors, which is a dts parameter.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
---
drivers/pci/host/Kconfig | 7 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pcie-altera-msi.c | 318 +++++++++++++++++++++++++++++++++++++
3 files changed, 326 insertions(+)
create mode 100644 drivers/pci/host/pcie-altera-msi.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index af19039..a8b87fd 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -154,4 +154,11 @@ config PCIE_ALTERA
Say Y here if you want to enable PCIe controller support for Altera
SoCFPGA family of SoCs.

+config PCIE_ALTERA_MSI
+ bool "Altera PCIe MSI feature"
+ depends on PCI_MSI && PCIE_ALTERA
+ help
+ Say Y here if you want PCIe MSI support for the Altera SocFPGA SoC.
+ This MSI driver supports Altera MSI to GIC controller IP.
+
endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 6954f76..6c4913d 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_PCIE_IPROC) += pcie-iproc.o
obj-$(CONFIG_PCIE_IPROC_PLATFORM) += pcie-iproc-platform.o
obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
+obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
diff --git a/drivers/pci/host/pcie-altera-msi.c b/drivers/pci/host/pcie-altera-msi.c
new file mode 100644
index 0000000..b852b51
--- /dev/null
+++ b/drivers/pci/host/pcie-altera-msi.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright Altera Corporation (C) 2013-2015. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define MSI_STATUS 0x0
+#define MSI_ERROR 0x4
+#define MSI_INTMASK 0x8
+
+#define MAX_MSI_VECTORS 32
+struct altera_msi {
+ DECLARE_BITMAP(used, MAX_MSI_VECTORS);
+ struct mutex lock; /* proctect used variable */
+ struct platform_device *pdev;
+ struct irq_domain *msi_domain;
+ void __iomem *csr_base;
+ void __iomem *vector_base;
+ u32 vector_phy;
+ u32 num_of_vectors;
+ int irq;
+};
+
+static inline void msi_writel(struct altera_msi *msi, u32 value, u32 reg)
+{
+ writel(value, msi->csr_base + reg);
+}
+
+static inline u32 msi_readl(struct altera_msi *msi, u32 reg)
+{
+ return readl(msi->csr_base + reg);
+}
+
+static irqreturn_t altera_msi_isr(int irq, void *data)
+{
+ struct altera_msi *msi = data;
+ unsigned long status;
+ u32 num_of_vectors = msi->num_of_vectors;
+ u32 processed = 0;
+ u32 offset;
+
+ do {
+ status = msi_readl(msi, MSI_STATUS);
+ if (!status)
+ break;
+
+ do {
+ offset = find_first_bit(&status, num_of_vectors);
+ /* Dummy read from vector to clear the interrupt */
+ readl(msi->vector_base + (offset * sizeof(u32)));
+
+ irq = irq_find_mapping(msi->msi_domain->parent, offset);
+ if (irq) {
+ if (test_bit(offset, msi->used))
+ generic_handle_irq(irq);
+ else
+ dev_info(&msi->pdev->dev, "unhandled MSI\n");
+ } else
+ dev_info(&msi->pdev->dev, "unexpected MSI\n");
+
+ /* Clear the bit from status and repeat without reading
+ * again status register. */
+ clear_bit(offset, &status);
+ processed++;
+ } while (status);
+ } while (1);
+
+ return processed > 0 ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static struct irq_chip altera_msi_irq_chip = {
+ .name = "Altera PCIe 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 altera_msi_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+ .chip = &altera_msi_irq_chip,
+};
+
+static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ struct altera_msi *msi = irq_data_get_irq_chip_data(data);
+ u32 mask;
+
+ msg->address_lo = msi->vector_phy + (data->hwirq * sizeof(u32));
+ /* 32 bit address only */
+ msg->address_hi = 0;
+ msg->data = data->hwirq;
+
+ mask = msi_readl(msi, MSI_INTMASK);
+ mask |= 1 << data->hwirq;
+ msi_writel(msi, mask, MSI_INTMASK);
+ dev_dbg(&msi->pdev->dev, "msi#%d address_lo 0x%x\n", (int)data->hwirq,
+ msg->address_lo);
+}
+
+static int altera_msi_set_affinity(struct irq_data *irq_data,
+ const struct cpumask *mask, bool force)
+{
+ return irq_set_affinity(irq_data->hwirq, mask);
+}
+
+static struct irq_chip altera_msi_bottom_irq_chip = {
+ .name = "Altera MSI",
+ .irq_compose_msi_msg = altera_compose_msi_msg,
+ .irq_set_affinity = altera_msi_set_affinity,
+};
+
+static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct altera_msi *msi = domain->host_data;
+ int bit;
+
+ mutex_lock(&msi->lock);
+
+ bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
+ if (bit < msi->num_of_vectors)
+ set_bit(bit, msi->used);
+ else
+ bit = -ENOSPC;
+
+ mutex_unlock(&msi->lock);
+
+ if (bit < 0)
+ return bit;
+
+ irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
+ domain->host_data, handle_simple_irq,
+ NULL, NULL);
+ set_irq_flags(virq, IRQF_VALID);
+
+ return 0;
+}
+
+static void altera_irq_domain_free(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs)
+{
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+ struct altera_msi *msi = irq_data_get_irq_chip_data(d);
+ u32 mask;
+
+ mutex_lock(&msi->lock);
+
+ if (!test_bit(d->hwirq, msi->used))
+ dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
+ d->hwirq);
+ else {
+ clear_bit(d->hwirq, msi->used);
+ mask = msi_readl(msi, MSI_INTMASK);
+ mask &= ~(1 << d->hwirq);
+ msi_writel(msi, mask, MSI_INTMASK);
+ }
+
+ mutex_unlock(&msi->lock);
+}
+
+static const struct irq_domain_ops msi_domain_ops = {
+ .alloc = altera_irq_domain_alloc,
+ .free = altera_irq_domain_free,
+};
+
+static int altera_allocate_domains(struct altera_msi *msi)
+{
+ struct irq_domain *inner_domain;
+
+ inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
+ &msi_domain_ops, msi);
+ if (!inner_domain) {
+ dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
+ return -ENOMEM;
+ }
+
+ msi->msi_domain = pci_msi_create_irq_domain(
+ msi->pdev->dev.of_node,
+ &altera_msi_domain_info, inner_domain);
+ if (!msi->msi_domain) {
+ dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
+ irq_domain_remove(inner_domain);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void altera_free_domains(struct altera_msi *msi)
+{
+ struct irq_domain *inner_domain = msi->msi_domain->parent;
+
+ irq_domain_remove(msi->msi_domain);
+ irq_domain_remove(inner_domain);
+}
+
+int altera_msi_probe(struct platform_device *pdev)
+{
+ struct altera_msi *msi;
+ struct device_node *np = pdev->dev.of_node;
+ struct resource *res;
+ int ret;
+
+ msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
+ GFP_KERNEL);
+ if (!msi)
+ return -ENOMEM;
+
+ mutex_init(&msi->lock);
+ msi->pdev = pdev;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
+ msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(msi->csr_base)) {
+ dev_err(&pdev->dev, "get csr resource failed\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+ "vector_slave");
+ msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(msi->vector_base)) {
+ dev_err(&pdev->dev, "get vector slave resource failed\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ msi->vector_phy = res->start;
+
+ if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
+ dev_err(&pdev->dev, "failed to parse the number of vectors\n");
+ return -EINVAL;
+ }
+
+ ret = altera_allocate_domains(msi);
+ if (ret)
+ return ret;
+
+ msi->irq = platform_get_irq(pdev, 0);
+ if (msi->irq <= 0) {
+ dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
+ ret = -ENODEV;
+ goto err;
+ }
+
+ ret = devm_request_irq(&pdev->dev, msi->irq, altera_msi_isr, 0,
+ altera_msi_irq_chip.name, msi);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request IRQ: %d\n", ret);
+ goto err;
+ }
+
+ platform_set_drvdata(pdev, msi);
+
+ return 0;
+
+err:
+ irq_domain_remove(msi->msi_domain);
+ return ret;
+}
+
+static int altera_msi_remove(struct platform_device *pdev)
+{
+ struct altera_msi *msi = platform_get_drvdata(pdev);
+
+ msi_writel(msi, 0, MSI_INTMASK);
+
+ altera_free_domains(msi);
+
+ platform_set_drvdata(pdev, NULL);
+ return 0;
+}
+
+static const struct of_device_id altera_msi_of_match[] = {
+ { .compatible = "altr,msi-1.0", NULL },
+ { },
+};
+MODULE_DEVICE_TABLE(of, altera_msi_of_match);
+
+static struct platform_driver altera_msi_driver = {
+ .driver = {
+ .name = "altera-msi",
+ .owner = THIS_MODULE,
+ .of_match_table = altera_msi_of_match,
+ },
+ .probe = altera_msi_probe,
+ .remove = altera_msi_remove,
+};
+
+static int __init altera_msi_init(void)
+{
+ return platform_driver_register(&altera_msi_driver);
+}
+
+subsys_initcall(altera_msi_init);
+
+MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
+MODULE_DESCRIPTION("Altera PCIe MSI support");
+MODULE_LICENSE("GPL v2");
--
1.8.2.1


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