diff options
Diffstat (limited to 'arch/powerpc/sysdev/mpic_u3msi.c')
| -rw-r--r-- | arch/powerpc/sysdev/mpic_u3msi.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/mpic_u3msi.c b/arch/powerpc/sysdev/mpic_u3msi.c new file mode 100644 index 000000000..1d8cfdfdf --- /dev/null +++ b/arch/powerpc/sysdev/mpic_u3msi.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2006, Segher Boessenkool, IBM Corporation. + * Copyright 2006-2007, Michael Ellerman, IBM Corporation. + */ + +#include <linux/irq.h> +#include <linux/irqdomain.h> +#include <linux/msi.h> +#include <asm/mpic.h> +#include <asm/hw_irq.h> +#include <asm/ppc-pci.h> +#include <asm/msi_bitmap.h> + +#include "mpic.h" + +/* A bit ugly, can we get this from the pci_dev somehow? */ +static struct mpic *msi_mpic; + +static void mpic_u3msi_mask_irq(struct irq_data *data) +{ + pci_msi_mask_irq(data); + mpic_mask_irq(data); +} + +static void mpic_u3msi_unmask_irq(struct irq_data *data) +{ + mpic_unmask_irq(data); + pci_msi_unmask_irq(data); +} + +static struct irq_chip mpic_u3msi_chip = { + .irq_shutdown = mpic_u3msi_mask_irq, + .irq_mask = mpic_u3msi_mask_irq, + .irq_unmask = mpic_u3msi_unmask_irq, + .irq_eoi = mpic_end_irq, + .irq_set_type = mpic_set_irq_type, + .irq_set_affinity = mpic_set_affinity, + .name = "MPIC-U3MSI", +}; + +static u64 read_ht_magic_addr(struct pci_dev *pdev, unsigned int pos) +{ + u8 flags; + u32 tmp; + u64 addr; + + pci_read_config_byte(pdev, pos + HT_MSI_FLAGS, &flags); + + if (flags & HT_MSI_FLAGS_FIXED) + return HT_MSI_FIXED_ADDR; + + pci_read_config_dword(pdev, pos + HT_MSI_ADDR_LO, &tmp); + addr = tmp & HT_MSI_ADDR_LO_MASK; + pci_read_config_dword(pdev, pos + HT_MSI_ADDR_HI, &tmp); + addr = addr | ((u64)tmp << 32); + + return addr; +} + +static u64 find_ht_magic_addr(struct pci_dev *pdev, unsigned int hwirq) +{ + struct pci_bus *bus; + unsigned int pos; + + for (bus = pdev->bus; bus && bus->self; bus = bus->parent) { + pos = pci_find_ht_capability(bus->self, HT_CAPTYPE_MSI_MAPPING); + if (pos) + return read_ht_magic_addr(bus->self, pos); + } + + return 0; +} + +static u64 find_u4_magic_addr(struct pci_dev *pdev, unsigned int hwirq) +{ + struct pci_controller *hose = pci_bus_to_host(pdev->bus); + + /* U4 PCIe MSIs need to write to the special register in + * the bridge that generates interrupts. There should be + * theoretically a register at 0xf8005000 where you just write + * the MSI number and that triggers the right interrupt, but + * unfortunately, this is busted in HW, the bridge endian swaps + * the value and hits the wrong nibble in the register. + * + * So instead we use another register set which is used normally + * for converting HT interrupts to MPIC interrupts, which decodes + * the interrupt number as part of the low address bits + * + * This will not work if we ever use more than one legacy MSI in + * a block but we never do. For one MSI or multiple MSI-X where + * each interrupt address can be specified separately, it works + * just fine. + */ + if (of_device_is_compatible(hose->dn, "u4-pcie") || + of_device_is_compatible(hose->dn, "U4-pcie")) + return 0xf8004000 | (hwirq << 4); + + return 0; +} + +static void u3msi_teardown_msi_irqs(struct pci_dev *pdev) +{ + struct msi_desc *entry; + irq_hw_number_t hwirq; + + msi_for_each_desc(entry, &pdev->dev, MSI_DESC_ASSOCIATED) { + hwirq = virq_to_hw(entry->irq); + irq_set_msi_desc(entry->irq, NULL); + irq_dispose_mapping(entry->irq); + msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1); + } +} + +static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) +{ + unsigned int virq; + struct msi_desc *entry; + struct msi_msg msg; + u64 addr; + int hwirq; + + if (type == PCI_CAP_ID_MSIX) + pr_debug("u3msi: MSI-X untested, trying anyway.\n"); + + /* If we can't find a magic address then MSI ain't gonna work */ + if (find_ht_magic_addr(pdev, 0) == 0 && + find_u4_magic_addr(pdev, 0) == 0) { + pr_debug("u3msi: no magic address found for %s\n", + pci_name(pdev)); + return -ENXIO; + } + + msi_for_each_desc(entry, &pdev->dev, MSI_DESC_NOTASSOCIATED) { + hwirq = msi_bitmap_alloc_hwirqs(&msi_mpic->msi_bitmap, 1); + if (hwirq < 0) { + pr_debug("u3msi: failed allocating hwirq\n"); + return hwirq; + } + + addr = find_ht_magic_addr(pdev, hwirq); + if (addr == 0) + addr = find_u4_magic_addr(pdev, hwirq); + msg.address_lo = addr & 0xFFFFFFFF; + msg.address_hi = addr >> 32; + + virq = irq_create_mapping(msi_mpic->irqhost, hwirq); + if (!virq) { + pr_debug("u3msi: failed mapping hwirq 0x%x\n", hwirq); + msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1); + return -ENOSPC; + } + + irq_set_msi_desc(virq, entry); + irq_set_chip(virq, &mpic_u3msi_chip); + irq_set_irq_type(virq, IRQ_TYPE_EDGE_RISING); + + pr_debug("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n", + virq, hwirq, (unsigned long)addr); + + printk("u3msi: allocated virq 0x%x (hw 0x%x) addr 0x%lx\n", + virq, hwirq, (unsigned long)addr); + msg.data = hwirq; + pci_write_msi_msg(virq, &msg); + + hwirq++; + } + + return 0; +} + +int __init mpic_u3msi_init(struct mpic *mpic) +{ + int rc; + struct pci_controller *phb; + + rc = mpic_msi_init_allocator(mpic); + if (rc) { + pr_debug("u3msi: Error allocating bitmap!\n"); + return rc; + } + + pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n"); + + BUG_ON(msi_mpic); + msi_mpic = mpic; + + list_for_each_entry(phb, &hose_list, list_node) { + WARN_ON(phb->controller_ops.setup_msi_irqs); + phb->controller_ops.setup_msi_irqs = u3msi_setup_msi_irqs; + phb->controller_ops.teardown_msi_irqs = u3msi_teardown_msi_irqs; + } + + return 0; +} |