diff options
Diffstat (limited to 'arch/powerpc/sysdev/ppc4xx_hsta_msi.c')
| -rw-r--r-- | arch/powerpc/sysdev/ppc4xx_hsta_msi.c | 215 |
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 00000000000..11c888416f0 --- /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); |