132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
/*
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* Enables/disables PCIe ECRC checking.
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*
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* (C) Copyright 2009 Hewlett-Packard Development Company, L.P.
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* Andrew Patterson <andrew.patterson@hp.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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* 02111-1307, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/pci.h>
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#include <linux/pci_regs.h>
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#include <linux/errno.h>
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#include "../../pci.h"
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#define ECRC_POLICY_DEFAULT 0 /* ECRC set by BIOS */
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#define ECRC_POLICY_OFF 1 /* ECRC off for performance */
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#define ECRC_POLICY_ON 2 /* ECRC on for data integrity */
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static int ecrc_policy = ECRC_POLICY_DEFAULT;
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static const char *ecrc_policy_str[] = {
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[ECRC_POLICY_DEFAULT] = "bios",
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[ECRC_POLICY_OFF] = "off",
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[ECRC_POLICY_ON] = "on"
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};
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/**
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* enable_ercr_checking - enable PCIe ECRC checking for a device
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* @dev: the PCI device
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*
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* Returns 0 on success, or negative on failure.
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*/
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static int enable_ecrc_checking(struct pci_dev *dev)
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{
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int pos;
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u32 reg32;
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if (!dev->is_pcie)
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return -ENODEV;
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pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
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if (!pos)
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return -ENODEV;
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pci_read_config_dword(dev, pos + PCI_ERR_CAP, ®32);
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if (reg32 & PCI_ERR_CAP_ECRC_GENC)
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reg32 |= PCI_ERR_CAP_ECRC_GENE;
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if (reg32 & PCI_ERR_CAP_ECRC_CHKC)
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reg32 |= PCI_ERR_CAP_ECRC_CHKE;
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pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);
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return 0;
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}
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/**
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* disable_ercr_checking - disables PCIe ECRC checking for a device
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* @dev: the PCI device
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*
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* Returns 0 on success, or negative on failure.
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*/
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static int disable_ecrc_checking(struct pci_dev *dev)
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{
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int pos;
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u32 reg32;
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if (!dev->is_pcie)
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return -ENODEV;
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pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
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if (!pos)
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return -ENODEV;
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pci_read_config_dword(dev, pos + PCI_ERR_CAP, ®32);
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reg32 &= ~(PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
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pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);
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return 0;
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}
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/**
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* pcie_set_ecrc_checking - set/unset PCIe ECRC checking for a device based on global policy
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* @dev: the PCI device
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*/
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void pcie_set_ecrc_checking(struct pci_dev *dev)
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{
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switch (ecrc_policy) {
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case ECRC_POLICY_DEFAULT:
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return;
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case ECRC_POLICY_OFF:
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disable_ecrc_checking(dev);
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break;
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case ECRC_POLICY_ON:
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enable_ecrc_checking(dev);
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break;
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default:
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return;
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}
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}
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/**
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* pcie_ecrc_get_policy - parse kernel command-line ecrc option
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*/
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void pcie_ecrc_get_policy(char *str)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(ecrc_policy_str); i++)
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if (!strncmp(str, ecrc_policy_str[i],
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strlen(ecrc_policy_str[i])))
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break;
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if (i >= ARRAY_SIZE(ecrc_policy_str))
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return;
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ecrc_policy = i;
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}
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