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-rw-r--r--arch/mips/cavium-octeon/msi.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/arch/mips/cavium-octeon/msi.c b/arch/mips/cavium-octeon/msi.c
new file mode 100644
index 00000000000..964b03b75a8
--- /dev/null
+++ b/arch/mips/cavium-octeon/msi.c
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+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005-2007 Cavium Networks
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/msi.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+
+#include <asm/octeon/octeon.h>
+#include <asm/octeon/cvmx-npi-defs.h>
+#include <asm/octeon/cvmx-pci-defs.h>
+#include <asm/octeon/cvmx-npei-defs.h>
+#include <asm/octeon/cvmx-pexp-defs.h>
+
+#include "pci-common.h"
+
+/*
+ * Each bit in msi_free_irq_bitmask represents a MSI interrupt that is
+ * in use.
+ */
+static uint64_t msi_free_irq_bitmask;
+
+/*
+ * Each bit in msi_multiple_irq_bitmask tells that the device using
+ * this bit in msi_free_irq_bitmask is also using the next bit. This
+ * is used so we can disable all of the MSI interrupts when a device
+ * uses multiple.
+ */
+static uint64_t msi_multiple_irq_bitmask;
+
+/*
+ * This lock controls updates to msi_free_irq_bitmask and
+ * msi_multiple_irq_bitmask.
+ */
+static DEFINE_SPINLOCK(msi_free_irq_bitmask_lock);
+
+
+/**
+ * Called when a driver request MSI interrupts instead of the
+ * legacy INT A-D. This routine will allocate multiple interrupts
+ * for MSI devices that support them. A device can override this by
+ * programming the MSI control bits [6:4] before calling
+ * pci_enable_msi().
+ *
+ * @param dev Device requesting MSI interrupts
+ * @param desc MSI descriptor
+ *
+ * Returns 0 on success.
+ */
+int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
+{
+ struct msi_msg msg;
+ uint16_t control;
+ int configured_private_bits;
+ int request_private_bits;
+ int irq;
+ int irq_step;
+ uint64_t search_mask;
+
+ /*
+ * Read the MSI config to figure out how many IRQs this device
+ * wants. Most devices only want 1, which will give
+ * configured_private_bits and request_private_bits equal 0.
+ */
+ pci_read_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS,
+ &control);
+
+ /*
+ * If the number of private bits has been configured then use
+ * that value instead of the requested number. This gives the
+ * driver the chance to override the number of interrupts
+ * before calling pci_enable_msi().
+ */
+ configured_private_bits = (control & PCI_MSI_FLAGS_QSIZE) >> 4;
+ if (configured_private_bits == 0) {
+ /* Nothing is configured, so use the hardware requested size */
+ request_private_bits = (control & PCI_MSI_FLAGS_QMASK) >> 1;
+ } else {
+ /*
+ * Use the number of configured bits, assuming the
+ * driver wanted to override the hardware request
+ * value.
+ */
+ request_private_bits = configured_private_bits;
+ }
+
+ /*
+ * The PCI 2.3 spec mandates that there are at most 32
+ * interrupts. If this device asks for more, only give it one.
+ */
+ if (request_private_bits > 5)
+ request_private_bits = 0;
+
+try_only_one:
+ /*
+ * The IRQs have to be aligned on a power of two based on the
+ * number being requested.
+ */
+ irq_step = 1 << request_private_bits;
+
+ /* Mask with one bit for each IRQ */
+ search_mask = (1 << irq_step) - 1;
+
+ /*
+ * We're going to search msi_free_irq_bitmask_lock for zero
+ * bits. This represents an MSI interrupt number that isn't in
+ * use.
+ */
+ spin_lock(&msi_free_irq_bitmask_lock);
+ for (irq = 0; irq < 64; irq += irq_step) {
+ if ((msi_free_irq_bitmask & (search_mask << irq)) == 0) {
+ msi_free_irq_bitmask |= search_mask << irq;
+ msi_multiple_irq_bitmask |= (search_mask >> 1) << irq;
+ break;
+ }
+ }
+ spin_unlock(&msi_free_irq_bitmask_lock);
+
+ /* Make sure the search for available interrupts didn't fail */
+ if (irq >= 64) {
+ if (request_private_bits) {
+ pr_err("arch_setup_msi_irq: Unable to find %d free "
+ "interrupts, trying just one",
+ 1 << request_private_bits);
+ request_private_bits = 0;
+ goto try_only_one;
+ } else
+ panic("arch_setup_msi_irq: Unable to find a free MSI "
+ "interrupt");
+ }
+
+ /* MSI interrupts start at logical IRQ OCTEON_IRQ_MSI_BIT0 */
+ irq += OCTEON_IRQ_MSI_BIT0;
+
+ switch (octeon_dma_bar_type) {
+ case OCTEON_DMA_BAR_TYPE_SMALL:
+ /* When not using big bar, Bar 0 is based at 128MB */
+ msg.address_lo =
+ ((128ul << 20) + CVMX_PCI_MSI_RCV) & 0xffffffff;
+ msg.address_hi = ((128ul << 20) + CVMX_PCI_MSI_RCV) >> 32;
+ case OCTEON_DMA_BAR_TYPE_BIG:
+ /* When using big bar, Bar 0 is based at 0 */
+ msg.address_lo = (0 + CVMX_PCI_MSI_RCV) & 0xffffffff;
+ msg.address_hi = (0 + CVMX_PCI_MSI_RCV) >> 32;
+ break;
+ case OCTEON_DMA_BAR_TYPE_PCIE:
+ /* When using PCIe, Bar 0 is based at 0 */
+ /* FIXME CVMX_NPEI_MSI_RCV* other than 0? */
+ msg.address_lo = (0 + CVMX_NPEI_PCIE_MSI_RCV) & 0xffffffff;
+ msg.address_hi = (0 + CVMX_NPEI_PCIE_MSI_RCV) >> 32;
+ break;
+ default:
+ panic("arch_setup_msi_irq: Invalid octeon_dma_bar_type\n");
+ }
+ msg.data = irq - OCTEON_IRQ_MSI_BIT0;
+
+ /* Update the number of IRQs the device has available to it */
+ control &= ~PCI_MSI_FLAGS_QSIZE;
+ control |= request_private_bits << 4;
+ pci_write_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS,
+ control);
+
+ set_irq_msi(irq, desc);
+ write_msi_msg(irq, &msg);
+ return 0;
+}
+
+
+/**
+ * Called when a device no longer needs its MSI interrupts. All
+ * MSI interrupts for the device are freed.
+ *
+ * @irq: The devices first irq number. There may be multple in sequence.
+ */
+void arch_teardown_msi_irq(unsigned int irq)
+{
+ int number_irqs;
+ uint64_t bitmask;
+
+ if ((irq < OCTEON_IRQ_MSI_BIT0) || (irq > OCTEON_IRQ_MSI_BIT63))
+ panic("arch_teardown_msi_irq: Attempted to teardown illegal "
+ "MSI interrupt (%d)", irq);
+ irq -= OCTEON_IRQ_MSI_BIT0;
+
+ /*
+ * Count the number of IRQs we need to free by looking at the
+ * msi_multiple_irq_bitmask. Each bit set means that the next
+ * IRQ is also owned by this device.
+ */
+ number_irqs = 0;
+ while ((irq+number_irqs < 64) &&
+ (msi_multiple_irq_bitmask & (1ull << (irq + number_irqs))))
+ number_irqs++;
+ number_irqs++;
+ /* Mask with one bit for each IRQ */
+ bitmask = (1 << number_irqs) - 1;
+ /* Shift the mask to the correct bit location */
+ bitmask <<= irq;
+ if ((msi_free_irq_bitmask & bitmask) != bitmask)
+ panic("arch_teardown_msi_irq: Attempted to teardown MSI "
+ "interrupt (%d) not in use", irq);
+
+ /* Checks are done, update the in use bitmask */
+ spin_lock(&msi_free_irq_bitmask_lock);
+ msi_free_irq_bitmask &= ~bitmask;
+ msi_multiple_irq_bitmask &= ~bitmask;
+ spin_unlock(&msi_free_irq_bitmask_lock);
+}
+
+
+/**
+ * Called by the interrupt handling code when an MSI interrupt
+ * occurs.
+ *
+ * @param cpl
+ * @param dev_id
+ *
+ * @return
+ */
+static irqreturn_t octeon_msi_interrupt(int cpl, void *dev_id)
+{
+ uint64_t msi_bits;
+ int irq;
+
+ if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_PCIE)
+ msi_bits = cvmx_read_csr(CVMX_PEXP_NPEI_MSI_RCV0);
+ else
+ msi_bits = cvmx_read_csr(CVMX_NPI_NPI_MSI_RCV);
+ irq = fls64(msi_bits);
+ if (irq) {
+ irq += OCTEON_IRQ_MSI_BIT0 - 1;
+ if (irq_desc[irq].action) {
+ do_IRQ(irq);
+ return IRQ_HANDLED;
+ } else {
+ pr_err("Spurious MSI interrupt %d\n", irq);
+ if (octeon_has_feature(OCTEON_FEATURE_PCIE)) {
+ /* These chips have PCIe */
+ cvmx_write_csr(CVMX_PEXP_NPEI_MSI_RCV0,
+ 1ull << (irq -
+ OCTEON_IRQ_MSI_BIT0));
+ } else {
+ /* These chips have PCI */
+ cvmx_write_csr(CVMX_NPI_NPI_MSI_RCV,
+ 1ull << (irq -
+ OCTEON_IRQ_MSI_BIT0));
+ }
+ }
+ }
+ return IRQ_NONE;
+}
+
+
+/**
+ * Initializes the MSI interrupt handling code
+ *
+ * @return
+ */
+int octeon_msi_initialize(void)
+{
+ int r;
+ if (octeon_has_feature(OCTEON_FEATURE_PCIE)) {
+ r = request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt,
+ IRQF_SHARED,
+ "MSI[0:63]", octeon_msi_interrupt);
+ } else if (octeon_is_pci_host()) {
+ r = request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt,
+ IRQF_SHARED,
+ "MSI[0:15]", octeon_msi_interrupt);
+ r += request_irq(OCTEON_IRQ_PCI_MSI1, octeon_msi_interrupt,
+ IRQF_SHARED,
+ "MSI[16:31]", octeon_msi_interrupt);
+ r += request_irq(OCTEON_IRQ_PCI_MSI2, octeon_msi_interrupt,
+ IRQF_SHARED,
+ "MSI[32:47]", octeon_msi_interrupt);
+ r += request_irq(OCTEON_IRQ_PCI_MSI3, octeon_msi_interrupt,
+ IRQF_SHARED,
+ "MSI[48:63]", octeon_msi_interrupt);
+ }
+ return 0;
+}
+
+subsys_initcall(octeon_msi_initialize);