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