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_irq.h> 14 #include <linux/of_platform.h> 15 #include <linux/pci.h> 16 #include <linux/semaphore.h> 17 #include <asm/msi_bitmap.h> 18 #include <asm/ppc-pci.h> 19 20 struct ppc4xx_hsta_msi { 21 struct device *dev; 22 23 /* The ioremapped HSTA MSI IO space */ 24 u32 __iomem *data; 25 26 /* Physical address of HSTA MSI IO space */ 27 u64 address; 28 struct msi_bitmap bmp; 29 30 /* An array mapping offsets to hardware IRQs */ 31 int *irq_map; 32 33 /* Number of hwirqs supported */ 34 int irq_count; 35 }; 36 static struct ppc4xx_hsta_msi ppc4xx_hsta_msi; 37 38 static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) 39 { 40 struct msi_msg msg; 41 struct msi_desc *entry; 42 int irq, hwirq; 43 u64 addr; 44 45 /* We don't support MSI-X */ 46 if (type == PCI_CAP_ID_MSIX) { 47 pr_debug("%s: MSI-X not supported.\n", __func__); 48 return -EINVAL; 49 } 50 51 msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) { 52 irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1); 53 if (irq < 0) { 54 pr_debug("%s: Failed to allocate msi interrupt\n", 55 __func__); 56 return irq; 57 } 58 59 hwirq = ppc4xx_hsta_msi.irq_map[irq]; 60 if (!hwirq) { 61 pr_err("%s: Failed mapping irq %d\n", __func__, irq); 62 return -EINVAL; 63 } 64 65 /* 66 * HSTA generates interrupts on writes to 128-bit aligned 67 * addresses. 68 */ 69 addr = ppc4xx_hsta_msi.address + irq*0x10; 70 msg.address_hi = upper_32_bits(addr); 71 msg.address_lo = lower_32_bits(addr); 72 73 /* Data is not used by the HSTA. */ 74 msg.data = 0; 75 76 pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq, 77 (((u64) msg.address_hi) << 32) | msg.address_lo); 78 79 if (irq_set_msi_desc(hwirq, entry)) { 80 pr_err( 81 "%s: Invalid hwirq %d specified in device tree\n", 82 __func__, hwirq); 83 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); 84 return -EINVAL; 85 } 86 pci_write_msi_msg(hwirq, &msg); 87 } 88 89 return 0; 90 } 91 92 static int hsta_find_hwirq_offset(int hwirq) 93 { 94 int irq; 95 96 /* Find the offset given the hwirq */ 97 for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++) 98 if (ppc4xx_hsta_msi.irq_map[irq] == hwirq) 99 return irq; 100 101 return -EINVAL; 102 } 103 104 static void hsta_teardown_msi_irqs(struct pci_dev *dev) 105 { 106 struct msi_desc *entry; 107 int irq; 108 109 msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) { 110 irq = hsta_find_hwirq_offset(entry->irq); 111 112 /* entry->irq should always be in irq_map */ 113 BUG_ON(irq < 0); 114 irq_set_msi_desc(entry->irq, NULL); 115 msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1); 116 pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__, 117 entry->irq, irq); 118 } 119 } 120 121 static int hsta_msi_probe(struct platform_device *pdev) 122 { 123 struct device *dev = &pdev->dev; 124 struct resource *mem; 125 int irq, ret, irq_count; 126 struct pci_controller *phb; 127 128 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 129 if (!mem) { 130 dev_err(dev, "Unable to get mmio space\n"); 131 return -EINVAL; 132 } 133 134 irq_count = of_irq_count(dev->of_node); 135 if (!irq_count) { 136 dev_err(dev, "Unable to find IRQ range\n"); 137 return -EINVAL; 138 } 139 140 ppc4xx_hsta_msi.dev = dev; 141 ppc4xx_hsta_msi.address = mem->start; 142 ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem)); 143 ppc4xx_hsta_msi.irq_count = irq_count; 144 if (!ppc4xx_hsta_msi.data) { 145 dev_err(dev, "Unable to map memory\n"); 146 return -ENOMEM; 147 } 148 149 ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node); 150 if (ret) 151 goto out; 152 153 ppc4xx_hsta_msi.irq_map = kmalloc_array(irq_count, sizeof(int), 154 GFP_KERNEL); 155 if (!ppc4xx_hsta_msi.irq_map) { 156 ret = -ENOMEM; 157 goto out1; 158 } 159 160 /* Setup a mapping from irq offsets to hardware irq numbers */ 161 for (irq = 0; irq < irq_count; irq++) { 162 ppc4xx_hsta_msi.irq_map[irq] = 163 irq_of_parse_and_map(dev->of_node, irq); 164 if (!ppc4xx_hsta_msi.irq_map[irq]) { 165 dev_err(dev, "Unable to map IRQ\n"); 166 ret = -EINVAL; 167 goto out2; 168 } 169 } 170 171 list_for_each_entry(phb, &hose_list, list_node) { 172 phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs; 173 phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs; 174 } 175 return 0; 176 177 out2: 178 kfree(ppc4xx_hsta_msi.irq_map); 179 180 out1: 181 msi_bitmap_free(&ppc4xx_hsta_msi.bmp); 182 183 out: 184 iounmap(ppc4xx_hsta_msi.data); 185 return ret; 186 } 187 188 static const struct of_device_id hsta_msi_ids[] = { 189 { 190 .compatible = "ibm,hsta-msi", 191 }, 192 {} 193 }; 194 195 static struct platform_driver hsta_msi_driver = { 196 .probe = hsta_msi_probe, 197 .driver = { 198 .name = "hsta-msi", 199 .of_match_table = hsta_msi_ids, 200 }, 201 }; 202 203 static int hsta_msi_init(void) 204 { 205 return platform_driver_register(&hsta_msi_driver); 206 } 207 subsys_initcall(hsta_msi_init); 208