1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for 4 * generation of the interrupt. 5 * 6 * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/interrupt.h> 11 #include <linux/msi.h> 12 #include <linux/of.h> 13 #include <linux/of_platform.h> 14 #include <linux/pci.h> 15 #include <linux/semaphore.h> 16 #include <asm/msi_bitmap.h> 17 #include <asm/ppc-pci.h> 18 19 struct ppc4xx_hsta_msi { 20 struct device *dev; 21 22 /* The ioremapped HSTA MSI IO space */ 23 u32 __iomem *data; 24 25 /* Physical address of HSTA MSI IO space */ 26 u64 address; 27 struct msi_bitmap bmp; 28 29 /* An array mapping offsets to hardware IRQs */ 30 int *irq_map; 31 32 /* Number of hwirqs supported */ 33 int irq_count; 34 }; 35 static struct ppc4xx_hsta_msi ppc4xx_hsta_msi; 36 37 static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) 38 { 39 struct msi_msg msg; 40 struct msi_desc *entry; 41 int irq, hwirq; 42 u64 addr; 43 44 /* We don't support MSI-X */ 45 if (type == PCI_CAP_ID_MSIX) { 46 pr_debug("%s: MSI-X not supported.\n", __func__); 47 return -EINVAL; 48 } 49 50 msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) { 51 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1); 52 if (irq < 0) { 53 pr_debug("%s: Failed to allocate msi interrupt\n", 54 __func__); 55 return irq; 56 } 57 58 hwirq = ppc4xx_hsta_msi.irq_map[irq]; 59 if (!hwirq) { 60 pr_err("%s: Failed mapping irq %d\n", __func__, irq); 61 return -EINVAL; 62 } 63 64 /* 65 * HSTA generates interrupts on writes to 128-bit aligned 66 * addresses. 67 */ 68 addr = ppc4xx_hsta_msi.address + irq*0x10; 69 msg.address_hi = upper_32_bits(addr); 70 msg.address_lo = lower_32_bits(addr); 71 72 /* Data is not used by the HSTA. */ 73 msg.data = 0; 74 75 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq, 76 (((u64) msg.address_hi) << 32) | msg.address_lo); 77 78 if (irq_set_msi_desc(hwirq, entry)) { 79 pr_err( 80 "%s: Invalid hwirq %d specified in device tree\n", 81 __func__, hwirq); 82 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); 83 return -EINVAL; 84 } 85 pci_write_msi_msg(hwirq, &msg); 86 } 87 88 return 0; 89 } 90 91 static int hsta_find_hwirq_offset(int hwirq) 92 { 93 int irq; 94 95 /* Find the offset given the hwirq */ 96 for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++) 97 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq) 98 return irq; 99 100 return -EINVAL; 101 } 102 103 static void hsta_teardown_msi_irqs(struct pci_dev *dev) 104 { 105 struct msi_desc *entry; 106 int irq; 107 108 msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) { 109 irq = hsta_find_hwirq_offset(entry->irq); 110 111 /* entry->irq should always be in irq_map */ 112 BUG_ON(irq < 0); 113 irq_set_msi_desc(entry->irq, NULL); 114 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); 115 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__, 116 entry->irq, irq); 117 } 118 } 119 120 static int hsta_msi_probe(struct platform_device *pdev) 121 { 122 struct device *dev = &pdev->dev; 123 struct resource *mem; 124 int irq, ret, irq_count; 125 struct pci_controller *phb; 126 127 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 128 if (!mem) { 129 dev_err(dev, "Unable to get mmio space\n"); 130 return -EINVAL; 131 } 132 133 irq_count = of_irq_count(dev->of_node); 134 if (!irq_count) { 135 dev_err(dev, "Unable to find IRQ range\n"); 136 return -EINVAL; 137 } 138 139 ppc4xx_hsta_msi.dev = dev; 140 ppc4xx_hsta_msi.address = mem->start; 141 ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem)); 142 ppc4xx_hsta_msi.irq_count = irq_count; 143 if (!ppc4xx_hsta_msi.data) { 144 dev_err(dev, "Unable to map memory\n"); 145 return -ENOMEM; 146 } 147 148 ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node); 149 if (ret) 150 goto out; 151 152 ppc4xx_hsta_msi.irq_map = kmalloc_array(irq_count, sizeof(int), 153 GFP_KERNEL); 154 if (!ppc4xx_hsta_msi.irq_map) { 155 ret = -ENOMEM; 156 goto out1; 157 } 158 159 /* Setup a mapping from irq offsets to hardware irq numbers */ 160 for (irq = 0; irq < irq_count; irq++) { 161 ppc4xx_hsta_msi.irq_map[irq] = 162 irq_of_parse_and_map(dev->of_node, irq); 163 if (!ppc4xx_hsta_msi.irq_map[irq]) { 164 dev_err(dev, "Unable to map IRQ\n"); 165 ret = -EINVAL; 166 goto out2; 167 } 168 } 169 170 list_for_each_entry(phb, &hose_list, list_node) { 171 phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs; 172 phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs; 173 } 174 return 0; 175 176 out2: 177 kfree(ppc4xx_hsta_msi.irq_map); 178 179 out1: 180 msi_bitmap_free(&ppc4xx_hsta_msi.bmp); 181 182 out: 183 iounmap(ppc4xx_hsta_msi.data); 184 return ret; 185 } 186 187 static const struct of_device_id hsta_msi_ids[] = { 188 { 189 .compatible = "ibm,hsta-msi", 190 }, 191 {} 192 }; 193 194 static struct platform_driver hsta_msi_driver = { 195 .probe = hsta_msi_probe, 196 .driver = { 197 .name = "hsta-msi", 198 .of_match_table = hsta_msi_ids, 199 }, 200 }; 201 202 static int hsta_msi_init(void) 203 { 204 return platform_driver_register(&hsta_msi_driver); 205 } 206 subsys_initcall(hsta_msi_init); 207