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-rw-r--r--arch/powerpc/sysdev/mpic_u3msi.c196
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/mpic_u3msi.c b/arch/powerpc/sysdev/mpic_u3msi.c
new file mode 100644
index 0000000000..492cb03c0b
--- /dev/null
+++ b/arch/powerpc/sysdev/mpic_u3msi.c
@@ -0,0 +1,196 @@
+// 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);
+ entry->irq = 0;
+ 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;
+}