/*
* 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;
}
