diff options
Diffstat (limited to 'drivers/dma/ioat_dca.c')
| -rw-r--r-- | drivers/dma/ioat_dca.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c new file mode 100644 index 00000000000..2ae04c30ede --- /dev/null +++ b/drivers/dma/ioat_dca.c @@ -0,0 +1,263 @@ +/* + * Intel I/OAT DMA Linux driver + * Copyright(c) 2007 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + * The full GNU General Public License is included in this distribution in + * the file called "COPYING". + * + */ + +#include <linux/kernel.h> +#include <linux/pci.h> +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/dca.h> + +/* either a kernel change is needed, or we need something like this in kernel */ +#ifndef CONFIG_SMP +#include <asm/smp.h> +#undef cpu_physical_id +#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24) +#endif + +#include "ioatdma.h" +#include "ioatdma_registers.h" + +/* + * Bit 16 of a tag map entry is the "valid" bit, if it is set then bits 0:15 + * contain the bit number of the APIC ID to map into the DCA tag. If the valid + * bit is not set, then the value must be 0 or 1 and defines the bit in the tag. + */ +#define DCA_TAG_MAP_VALID 0x80 + +/* + * "Legacy" DCA systems do not implement the DCA register set in the + * I/OAT device. Software needs direct support for their tag mappings. + */ + +#define APICID_BIT(x) (DCA_TAG_MAP_VALID | (x)) +#define IOAT_TAG_MAP_LEN 8 + +static u8 ioat_tag_map_BNB[IOAT_TAG_MAP_LEN] = { + 1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), }; +static u8 ioat_tag_map_SCNB[IOAT_TAG_MAP_LEN] = { + 1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), }; +static u8 ioat_tag_map_CNB[IOAT_TAG_MAP_LEN] = { + 1, APICID_BIT(1), APICID_BIT(3), APICID_BIT(4), APICID_BIT(2), }; +static u8 ioat_tag_map_UNISYS[IOAT_TAG_MAP_LEN] = { 0 }; + +/* pack PCI B/D/F into a u16 */ +static inline u16 dcaid_from_pcidev(struct pci_dev *pci) +{ + return (pci->bus->number << 8) | pci->devfn; +} + +static int dca_enabled_in_bios(void) +{ + /* CPUID level 9 returns DCA configuration */ + /* Bit 0 indicates DCA enabled by the BIOS */ + unsigned long cpuid_level_9; + int res; + + cpuid_level_9 = cpuid_eax(9); + res = test_bit(0, &cpuid_level_9); + if (!res) + printk(KERN_ERR "ioat dma: DCA is disabled in BIOS\n"); + + return res; +} + +static int system_has_dca_enabled(void) +{ + if (boot_cpu_has(X86_FEATURE_DCA)) + return dca_enabled_in_bios(); + + printk(KERN_ERR "ioat dma: boot cpu doesn't have X86_FEATURE_DCA\n"); + return 0; +} + +struct ioat_dca_slot { + struct pci_dev *pdev; /* requester device */ + u16 rid; /* requester id, as used by IOAT */ +}; + +#define IOAT_DCA_MAX_REQ 6 + +struct ioat_dca_priv { + void __iomem *iobase; + void *dca_base; + int max_requesters; + int requester_count; + u8 tag_map[IOAT_TAG_MAP_LEN]; + struct ioat_dca_slot req_slots[0]; +}; + +/* 5000 series chipset DCA Port Requester ID Table Entry Format + * [15:8] PCI-Express Bus Number + * [7:3] PCI-Express Device Number + * [2:0] PCI-Express Function Number + * + * 5000 series chipset DCA control register format + * [7:1] Reserved (0) + * [0] Ignore Function Number + */ + +static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev) +{ + struct ioat_dca_priv *ioatdca = dca_priv(dca); + struct pci_dev *pdev; + int i; + u16 id; + + /* This implementation only supports PCI-Express */ + if (dev->bus != &pci_bus_type) + return -ENODEV; + pdev = to_pci_dev(dev); + id = dcaid_from_pcidev(pdev); + + if (ioatdca->requester_count == ioatdca->max_requesters) + return -ENODEV; + + for (i = 0; i < ioatdca->max_requesters; i++) { + if (ioatdca->req_slots[i].pdev == NULL) { + /* found an empty slot */ + ioatdca->requester_count++; + ioatdca->req_slots[i].pdev = pdev; + ioatdca->req_slots[i].rid = id; + writew(id, ioatdca->dca_base + (i * 4)); + /* make sure the ignore function bit is off */ + writeb(0, ioatdca->dca_base + (i * 4) + 2); + return i; + } + } + /* Error, ioatdma->requester_count is out of whack */ + return -EFAULT; +} + +static int ioat_dca_remove_requester(struct dca_provider *dca, + struct device *dev) +{ + struct ioat_dca_priv *ioatdca = dca_priv(dca); + struct pci_dev *pdev; + int i; + + /* This implementation only supports PCI-Express */ + if (dev->bus != &pci_bus_type) + return -ENODEV; + pdev = to_pci_dev(dev); + + for (i = 0; i < ioatdca->max_requesters; i++) { + if (ioatdca->req_slots[i].pdev == pdev) { + writew(0, ioatdca->dca_base + (i * 4)); + ioatdca->req_slots[i].pdev = NULL; + ioatdca->req_slots[i].rid = 0; + ioatdca->requester_count--; + return i; + } + } + return -ENODEV; +} + +static u8 ioat_dca_get_tag(struct dca_provider *dca, int cpu) +{ + struct ioat_dca_priv *ioatdca = dca_priv(dca); + int i, apic_id, bit, value; + u8 entry, tag; + + tag = 0; + apic_id = cpu_physical_id(cpu); + + for (i = 0; i < IOAT_TAG_MAP_LEN; i++) { + entry = ioatdca->tag_map[i]; + if (entry & DCA_TAG_MAP_VALID) { + bit = entry & ~DCA_TAG_MAP_VALID; + value = (apic_id & (1 << bit)) ? 1 : 0; + } else { + value = entry ? 1 : 0; + } + tag |= (value << i); + } + return tag; +} + +static struct dca_ops ioat_dca_ops = { + .add_requester = ioat_dca_add_requester, + .remove_requester = ioat_dca_remove_requester, + .get_tag = ioat_dca_get_tag, +}; + + +struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase) +{ + struct dca_provider *dca; + struct ioat_dca_priv *ioatdca; + u8 *tag_map = NULL; + int i; + int err; + + if (!system_has_dca_enabled()) + return NULL; + + /* I/OAT v1 systems must have a known tag_map to support DCA */ + switch (pdev->vendor) { + case PCI_VENDOR_ID_INTEL: + switch (pdev->device) { + case PCI_DEVICE_ID_INTEL_IOAT: + tag_map = ioat_tag_map_BNB; + break; + case PCI_DEVICE_ID_INTEL_IOAT_CNB: + tag_map = ioat_tag_map_CNB; + break; + case PCI_DEVICE_ID_INTEL_IOAT_SCNB: + tag_map = ioat_tag_map_SCNB; + break; + } + break; + case PCI_VENDOR_ID_UNISYS: + switch (pdev->device) { + case PCI_DEVICE_ID_UNISYS_DMA_DIRECTOR: + tag_map = ioat_tag_map_UNISYS; + break; + } + break; + } + if (tag_map == NULL) + return NULL; + + dca = alloc_dca_provider(&ioat_dca_ops, + sizeof(*ioatdca) + + (sizeof(struct ioat_dca_slot) * IOAT_DCA_MAX_REQ)); + if (!dca) + return NULL; + + ioatdca = dca_priv(dca); + ioatdca->max_requesters = IOAT_DCA_MAX_REQ; + + ioatdca->dca_base = iobase + 0x54; + + /* copy over the APIC ID to DCA tag mapping */ + for (i = 0; i < IOAT_TAG_MAP_LEN; i++) + ioatdca->tag_map[i] = tag_map[i]; + + err = register_dca_provider(dca, &pdev->dev); + if (err) { + free_dca_provider(dca); + return NULL; + } + + return dca; +} + |