diff options
Diffstat (limited to 'drivers/dma/ioat/dca.c')
| -rw-r--r-- | drivers/dma/ioat/dca.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c new file mode 100644 index 000000000..eab2fdda2 --- /dev/null +++ b/drivers/dma/ioat/dca.c @@ -0,0 +1,354 @@ +/* + * Intel I/OAT DMA Linux driver + * Copyright(c) 2007 - 2009 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. + * + * 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 "dma.h" +#include "registers.h" + +/* + * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6 + * 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 + +#define DCA3_TAG_MAP_BIT_TO_INV 0x80 +#define DCA3_TAG_MAP_BIT_TO_SEL 0x40 +#define DCA3_TAG_MAP_LITERAL_VAL 0x1 + +#define DCA_TAG_MAP_MASK 0xDF + +/* expected tag map bytes for I/OAT ver.2 */ +#define DCA2_TAG_MAP_BYTE0 0x80 +#define DCA2_TAG_MAP_BYTE1 0x0 +#define DCA2_TAG_MAP_BYTE2 0x81 +#define DCA2_TAG_MAP_BYTE3 0x82 +#define DCA2_TAG_MAP_BYTE4 0x82 + +/* verify if tag map matches expected values */ +static inline int dca2_tag_map_valid(u8 *tag_map) +{ + return ((tag_map[0] == DCA2_TAG_MAP_BYTE0) && + (tag_map[1] == DCA2_TAG_MAP_BYTE1) && + (tag_map[2] == DCA2_TAG_MAP_BYTE2) && + (tag_map[3] == DCA2_TAG_MAP_BYTE3) && + (tag_map[4] == DCA2_TAG_MAP_BYTE4)); +} + +/* + * "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 + +/* 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(struct pci_dev *pdev) +{ + /* 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) + dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n"); + + return res; +} + +int system_has_dca_enabled(struct pci_dev *pdev) +{ + if (boot_cpu_has(X86_FEATURE_DCA)) + return dca_enabled_in_bios(pdev); + + dev_dbg(&pdev->dev, "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 +#define IOAT3_DCA_MAX_REQ 2 + +struct ioat_dca_priv { + void __iomem *iobase; + void __iomem *dca_base; + int max_requesters; + int requester_count; + u8 tag_map[IOAT_TAG_MAP_LEN]; + struct ioat_dca_slot req_slots[0]; +}; + +static int ioat_dca_dev_managed(struct dca_provider *dca, + struct device *dev) +{ + struct ioat_dca_priv *ioatdca = dca_priv(dca); + struct pci_dev *pdev; + int i; + + pdev = to_pci_dev(dev); + for (i = 0; i < ioatdca->max_requesters; i++) { + if (ioatdca->req_slots[i].pdev == pdev) + return 1; + } + return 0; +} + +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; + u16 global_req_table; + + /* This implementation only supports PCI-Express */ + if (!dev_is_pci(dev)) + 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; + global_req_table = + readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET); + writel(id | IOAT_DCA_GREQID_VALID, + ioatdca->iobase + global_req_table + (i * 4)); + 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; + u16 global_req_table; + + /* This implementation only supports PCI-Express */ + if (!dev_is_pci(dev)) + return -ENODEV; + pdev = to_pci_dev(dev); + + for (i = 0; i < ioatdca->max_requesters; i++) { + if (ioatdca->req_slots[i].pdev == pdev) { + global_req_table = + readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET); + writel(0, ioatdca->iobase + global_req_table + (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, + struct device *dev, + int cpu) +{ + u8 tag; + + struct ioat_dca_priv *ioatdca = dca_priv(dca); + int i, apic_id, bit, value; + u8 entry; + + tag = 0; + apic_id = cpu_physical_id(cpu); + + for (i = 0; i < IOAT_TAG_MAP_LEN; i++) { + entry = ioatdca->tag_map[i]; + if (entry & DCA3_TAG_MAP_BIT_TO_SEL) { + bit = entry & + ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV); + value = (apic_id & (1 << bit)) ? 1 : 0; + } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) { + bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV; + value = (apic_id & (1 << bit)) ? 0 : 1; + } else { + value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0; + } + tag |= (value << i); + } + + return tag; +} + +static const struct dca_ops ioat_dca_ops = { + .add_requester = ioat_dca_add_requester, + .remove_requester = ioat_dca_remove_requester, + .get_tag = ioat_dca_get_tag, + .dev_managed = ioat_dca_dev_managed, +}; + +static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset) +{ + int slots = 0; + u32 req; + u16 global_req_table; + + global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET); + if (global_req_table == 0) + return 0; + + do { + req = readl(iobase + global_req_table + (slots * sizeof(u32))); + slots++; + } while ((req & IOAT_DCA_GREQID_LASTID) == 0); + + return slots; +} + +static inline int dca3_tag_map_invalid(u8 *tag_map) +{ + /* + * If the tag map is not programmed by the BIOS the default is: + * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00 + * + * This an invalid map and will result in only 2 possible tags + * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that + * this entire definition is invalid. + */ + return ((tag_map[0] == DCA_TAG_MAP_VALID) && + (tag_map[1] == DCA_TAG_MAP_VALID) && + (tag_map[2] == DCA_TAG_MAP_VALID) && + (tag_map[3] == DCA_TAG_MAP_VALID) && + (tag_map[4] == DCA_TAG_MAP_VALID)); +} + +struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase) +{ + struct dca_provider *dca; + struct ioat_dca_priv *ioatdca; + int slots; + int i; + int err; + u16 dca_offset; + u16 csi_fsb_control; + u16 pcie_control; + u8 bit; + + union { + u64 full; + struct { + u32 low; + u32 high; + }; + } tag_map; + + if (!system_has_dca_enabled(pdev)) + return NULL; + + dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET); + if (dca_offset == 0) + return NULL; + + slots = ioat_dca_count_dca_slots(iobase, dca_offset); + if (slots == 0) + return NULL; + + dca = alloc_dca_provider(&ioat_dca_ops, + sizeof(*ioatdca) + + (sizeof(struct ioat_dca_slot) * slots)); + if (!dca) + return NULL; + + ioatdca = dca_priv(dca); + ioatdca->iobase = iobase; + ioatdca->dca_base = iobase + dca_offset; + ioatdca->max_requesters = slots; + + /* some bios might not know to turn these on */ + csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET); + if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) { + csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH; + writew(csi_fsb_control, + ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET); + } + pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET); + if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) { + pcie_control |= IOAT3_PCI_CONTROL_MEMWR; + writew(pcie_control, + ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET); + } + + + /* TODO version, compatibility and configuration checks */ + + /* copy out the APIC to DCA tag map */ + tag_map.low = + readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW); + tag_map.high = + readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH); + for (i = 0; i < 8; i++) { + bit = tag_map.full >> (8 * i); + ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK; + } + + if (dca3_tag_map_invalid(ioatdca->tag_map)) { + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); + pr_warn_once("%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n", + dev_driver_string(&pdev->dev), + dev_name(&pdev->dev)); + free_dca_provider(dca); + return NULL; + } + + err = register_dca_provider(dca, &pdev->dev); + if (err) { + free_dca_provider(dca); + return NULL; + } + + return dca; +} |