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linux/drivers/dma/ioat/dca.c
Gustavo A. R. Silva 25af5afe77 dmanegine: ioat/dca: Use struct_size() helper 
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct ioat_dca_priv {
	...
        struct ioat_dca_slot     req_slots[0];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*ioatdca) + (sizeof(struct ioat_dca_slot) * slots)

with:

struct_size(ioatdca, req_slots, slots)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20190828184015.GA4273@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2019-09-04 10:17:14 +05:30

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel I/OAT DMA Linux driver
* Copyright(c) 2007 - 2009 Intel Corporation.
*/
#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,
struct_size(ioatdca, req_slots, 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;
}
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