mirror of https://gitee.com/openkylin/linux.git
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
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#include <linux/pci.h>
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#include <linux/kernel.h>
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static int __init
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early_read_config_word(struct pci_channel *hose,
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int top_bus, int bus, int devfn, int offset, u16 *value)
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{
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struct pci_dev fake_dev;
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struct pci_bus fake_bus;
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fake_dev.bus = &fake_bus;
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fake_dev.sysdata = hose;
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fake_dev.devfn = devfn;
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fake_bus.number = bus;
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fake_bus.sysdata = hose;
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fake_bus.ops = hose->pci_ops;
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if (bus != top_bus)
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/* Fake a parent bus structure. */
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fake_bus.parent = &fake_bus;
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else
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fake_bus.parent = NULL;
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return pci_read_config_word(&fake_dev, offset, value);
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}
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int __init pci_is_66mhz_capable(struct pci_channel *hose,
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int top_bus, int current_bus)
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{
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u32 pci_devfn;
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unsigned short vid;
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int cap66 = -1;
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u16 stat;
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printk(KERN_INFO "PCI: Checking 66MHz capabilities...\n");
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for (pci_devfn = 0; pci_devfn < 0xff; pci_devfn++) {
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if (PCI_FUNC(pci_devfn))
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continue;
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if (early_read_config_word(hose, top_bus, current_bus,
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pci_devfn, PCI_VENDOR_ID, &vid) !=
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PCIBIOS_SUCCESSFUL)
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continue;
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if (vid == 0xffff)
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continue;
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/* check 66MHz capability */
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if (cap66 < 0)
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cap66 = 1;
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if (cap66) {
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early_read_config_word(hose, top_bus, current_bus,
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pci_devfn, PCI_STATUS, &stat);
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if (!(stat & PCI_STATUS_66MHZ)) {
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printk(KERN_DEBUG
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"PCI: %02x:%02x not 66MHz capable.\n",
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current_bus, pci_devfn);
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cap66 = 0;
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break;
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}
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}
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}
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return cap66 > 0;
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}
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