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/*
* 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;
/* We don't support MSI-X */
if (type == PCI_CAP_ID_MSIX) {
pr_debug("%s: MSI-X not supported.\n", __func__);
return -EINVAL;
}
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_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;
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);
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