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Diffstat (limited to 'arch/powerpc/sysdev/ppc4xx_hsta_msi.c')
-rw-r--r--arch/powerpc/sysdev/ppc4xx_hsta_msi.c215
1 files changed, 215 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/ppc4xx_hsta_msi.c b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
new file mode 100644
index 000000000000..11c888416f0a
--- /dev/null
+++ b/arch/powerpc/sysdev/ppc4xx_hsta_msi.c
@@ -0,0 +1,215 @@
+/*
+ * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
+ * generation of the interrupt.
+ *
+ * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM 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; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/semaphore.h>
+#include <asm/msi_bitmap.h>
+
+struct ppc4xx_hsta_msi {
+ struct device *dev;
+
+ /* The ioremapped HSTA MSI IO space */
+ u32 __iomem *data;
+
+ /* Physical address of HSTA MSI IO space */
+ u64 address;
+ struct msi_bitmap bmp;
+
+ /* An array mapping offsets to hardware IRQs */
+ int *irq_map;
+
+ /* Number of hwirqs supported */
+ int irq_count;
+};
+static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
+
+static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+ struct msi_msg msg;
+ struct msi_desc *entry;
+ int irq, hwirq;
+ u64 addr;
+
+ list_for_each_entry(entry, &dev->msi_list, list) {
+ irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
+ if (irq < 0) {
+ pr_debug("%s: Failed to allocate msi interrupt\n",
+ __func__);
+ return irq;
+ }
+
+ hwirq = ppc4xx_hsta_msi.irq_map[irq];
+ if (hwirq == NO_IRQ) {
+ pr_err("%s: Failed mapping irq %d\n", __func__, irq);
+ return -EINVAL;
+ }
+
+ /*
+ * HSTA generates interrupts on writes to 128-bit aligned
+ * addresses.
+ */
+ addr = ppc4xx_hsta_msi.address + irq*0x10;
+ msg.address_hi = upper_32_bits(addr);
+ msg.address_lo = lower_32_bits(addr);
+
+ /* Data is not used by the HSTA. */
+ msg.data = 0;
+
+ pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
+ (((u64) msg.address_hi) << 32) | msg.address_lo);
+
+ if (irq_set_msi_desc(hwirq, entry)) {
+ pr_err(
+ "%s: Invalid hwirq %d specified in device tree\n",
+ __func__, hwirq);
+ msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
+ return -EINVAL;
+ }
+ write_msi_msg(hwirq, &msg);
+ }
+
+ return 0;
+}
+
+static int hsta_find_hwirq_offset(int hwirq)
+{
+ int irq;
+
+ /* Find the offset given the hwirq */
+ for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
+ if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
+ return irq;
+
+ return -EINVAL;
+}
+
+static void hsta_teardown_msi_irqs(struct pci_dev *dev)
+{
+ struct msi_desc *entry;
+ int irq;
+
+ list_for_each_entry(entry, &dev->msi_list, list) {
+ if (entry->irq == NO_IRQ)
+ continue;
+
+ irq = hsta_find_hwirq_offset(entry->irq);
+
+ /* entry->irq should always be in irq_map */
+ BUG_ON(irq < 0);
+ irq_set_msi_desc(entry->irq, NULL);
+ msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
+ pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
+ entry->irq, irq);
+ }
+}
+
+static int hsta_msi_check_device(struct pci_dev *pdev, int nvec, int type)
+{
+ /* We don't support MSI-X */
+ if (type == PCI_CAP_ID_MSIX) {
+ pr_debug("%s: MSI-X not supported.\n", __func__);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int hsta_msi_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *mem;
+ int irq, ret, irq_count;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (IS_ERR(mem)) {
+ dev_err(dev, "Unable to get mmio space\n");
+ return -EINVAL;
+ }
+
+ irq_count = of_irq_count(dev->of_node);
+ if (!irq_count) {
+ dev_err(dev, "Unable to find IRQ range\n");
+ return -EINVAL;
+ }
+
+ ppc4xx_hsta_msi.dev = dev;
+ ppc4xx_hsta_msi.address = mem->start;
+ ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
+ ppc4xx_hsta_msi.irq_count = irq_count;
+ if (IS_ERR(ppc4xx_hsta_msi.data)) {
+ dev_err(dev, "Unable to map memory\n");
+ return -ENOMEM;
+ }
+
+ ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
+ if (ret)
+ goto out;
+
+ ppc4xx_hsta_msi.irq_map = kmalloc(sizeof(int) * irq_count, GFP_KERNEL);
+ if (IS_ERR(ppc4xx_hsta_msi.irq_map)) {
+ ret = -ENOMEM;
+ goto out1;
+ }
+
+ /* Setup a mapping from irq offsets to hardware irq numbers */
+ for (irq = 0; irq < irq_count; irq++) {
+ ppc4xx_hsta_msi.irq_map[irq] =
+ irq_of_parse_and_map(dev->of_node, irq);
+ if (ppc4xx_hsta_msi.irq_map[irq] == NO_IRQ) {
+ dev_err(dev, "Unable to map IRQ\n");
+ ret = -EINVAL;
+ goto out2;
+ }
+ }
+
+ ppc_md.setup_msi_irqs = hsta_setup_msi_irqs;
+ ppc_md.teardown_msi_irqs = hsta_teardown_msi_irqs;
+ ppc_md.msi_check_device = hsta_msi_check_device;
+ return 0;
+
+out2:
+ kfree(ppc4xx_hsta_msi.irq_map);
+
+out1:
+ msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
+
+out:
+ iounmap(ppc4xx_hsta_msi.data);
+ return ret;
+}
+
+static const struct of_device_id hsta_msi_ids[] = {
+ {
+ .compatible = "ibm,hsta-msi",
+ },
+ {}
+};
+
+static struct platform_driver hsta_msi_driver = {
+ .probe = hsta_msi_probe,
+ .driver = {
+ .name = "hsta-msi",
+ .owner = THIS_MODULE,
+ .of_match_table = hsta_msi_ids,
+ },
+};
+
+static int hsta_msi_init(void)
+{
+ return platform_driver_register(&hsta_msi_driver);
+}
+subsys_initcall(hsta_msi_init);