diff options
Diffstat (limited to 'arch/mips/cavium-octeon/msi.c')
| -rw-r--r-- | arch/mips/cavium-octeon/msi.c | 288 |
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 000000000000..964b03b75a8f --- /dev/null +++ b/arch/mips/cavium-octeon/msi.c @@ -0,0 +1,288 @@ +/* + * 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); |