Release 4.14 arch/x86/pci/mmconfig_64.c

// SPDX-License-Identifier: GPL-2.0
/*
 * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
 *
 * This is an 64bit optimized version that always keeps the full mmconfig
 * space mapped. This allows lockless config space operation.
 */

#include <linux/pci.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <linux/rcupdate.h>
#include <asm/e820/api.h>
#include <asm/pci_x86.h>


#define PREFIX "PCI: "



static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
{
	struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);

	if (cfg && cfg->virt)
		return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
	return NULL;
}

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11.11%
Andi Kleen
13
21.31%
2
22.22%
Al Viro
1
1.64%
1
11.11%
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9
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static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
			  unsigned int devfn, int reg, int len, u32 *value)
{
	char __iomem *addr;

	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
err:		*value = -1;
		return -EINVAL;
	}

	rcu_read_lock();
	addr = pci_dev_base(seg, bus, devfn);
	if (!addr) {
		rcu_read_unlock();
		goto err;
	}

	switch (len) {
	case 1:
		*value = mmio_config_readb(addr + reg);
		break;
	case 2:
		*value = mmio_config_readw(addr + reg);
		break;
	case 4:
		*value = mmio_config_readl(addr + reg);
		break;
	}
	rcu_read_unlock();

	return 0;
}

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12.50%
Jiang Liu
11
7.24%
1
12.50%
Dean Gaudet
3
1.97%
1
12.50%
Björn Helgaas
3
1.97%
1
12.50%
Al Viro
1
0.66%
1
12.50%
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152
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static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
			   unsigned int devfn, int reg, int len, u32 value)
{
	char __iomem *addr;

	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
		return -EINVAL;

	rcu_read_lock();
	addr = pci_dev_base(seg, bus, devfn);
	if (!addr) {
		rcu_read_unlock();
		return -EINVAL;
	}

	switch (len) {
	case 1:
		mmio_config_writeb(addr + reg, value);
		break;
	case 2:
		mmio_config_writew(addr + reg, value);
		break;
	case 4:
		mmio_config_writel(addr + reg, value);
		break;
	}
	rcu_read_unlock();

	return 0;
}

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Jiang Liu
11
7.91%
1
14.29%
Dean Gaudet
9
6.47%
1
14.29%
Björn Helgaas
3
2.16%
1
14.29%
Al Viro
1
0.72%
1
14.29%
Total
139
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7
100.00%


const struct pci_raw_ops pci_mmcfg = {
	.read =		pci_mmcfg_read,
	.write =	pci_mmcfg_write,
};



static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg)
{
	void __iomem *addr;
	u64 start, size;
	int num_buses;

	start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
	num_buses = cfg->end_bus - cfg->start_bus + 1;
	size = PCI_MMCFG_BUS_OFFSET(num_buses);
	addr = ioremap_nocache(start, size);
	if (addr)
		addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
	return addr;
}

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21
25.30%
1
20.00%
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83
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5
100.00%



int __init pci_mmcfg_arch_init(void)
{
	struct pci_mmcfg_region *cfg;

	list_for_each_entry(cfg, &pci_mmcfg_list, list)
		if (pci_mmcfg_arch_map(cfg)) {
			pci_mmcfg_arch_free();
			return 0;
		}

	raw_pci_ext_ops = &pci_mmcfg;

	return 1;
}

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Olivier Galibert
8
18.18%
1
12.50%
Jiang Liu
3
6.82%
1
12.50%
Yinghai Lu
3
6.82%
1
12.50%
Matthew Wilcox
1
2.27%
1
12.50%
Total
44
100.00%
8
100.00%



void __init pci_mmcfg_arch_free(void)
{
	struct pci_mmcfg_region *cfg;

	list_for_each_entry(cfg, &pci_mmcfg_list, list)
		pci_mmcfg_arch_unmap(cfg);
}

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1
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4
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int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg)
{
	cfg->virt = mcfg_ioremap(cfg);
	if (!cfg->virt) {
		pr_err(PREFIX "can't map MMCONFIG at %pR\n", &cfg->res);
		return -ENOMEM;
	}

	return 0;
}

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2.17%
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void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg)
{
	if (cfg && cfg->virt) {
		iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus));
		cfg->virt = NULL;
	}
}
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40
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90
14.17%
3
9.68%
Yinghai Lu
49
7.72%
2
6.45%
Ivan Kokshaysky
41
6.46%
1
3.23%
Hirofumi Ogawa
38
5.98%
1
3.23%
Greg Kroah-Hartman
27
4.25%
3
9.68%
Dean Gaudet
12
1.89%
1
3.23%
Olivier Galibert
8
1.26%
1
3.23%
Al Viro
3
0.47%
1
3.23%
Arjan van de Ven
2
0.31%
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3.23%
Jan Beulich
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0.16%
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Ingo Molnar
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Directory: arch/x86/pci

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