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// 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/msi.h>
#include <asm/mpic.h>
#include <asm/prom.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
* theorically 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 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;
}
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