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path: root/drivers/pci/pcie/aer/ecrc.c
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Diffstat (limited to 'drivers/pci/pcie/aer/ecrc.c')
-rw-r--r--drivers/pci/pcie/aer/ecrc.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/pci/pcie/aer/ecrc.c b/drivers/pci/pcie/aer/ecrc.c
new file mode 100644
index 00000000000..ece97df4df6
--- /dev/null
+++ b/drivers/pci/pcie/aer/ecrc.c
@@ -0,0 +1,131 @@
+/*
+ * Enables/disables PCIe ECRC checking.
+ *
+ * (C) Copyright 2009 Hewlett-Packard Development Company, L.P.
+ * Andrew Patterson <andrew.patterson@hp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
+#include <linux/errno.h>
+#include "../../pci.h"
+
+#define ECRC_POLICY_DEFAULT 0 /* ECRC set by BIOS */
+#define ECRC_POLICY_OFF 1 /* ECRC off for performance */
+#define ECRC_POLICY_ON 2 /* ECRC on for data integrity */
+
+static int ecrc_policy = ECRC_POLICY_DEFAULT;
+
+static const char *ecrc_policy_str[] = {
+ [ECRC_POLICY_DEFAULT] = "bios",
+ [ECRC_POLICY_OFF] = "off",
+ [ECRC_POLICY_ON] = "on"
+};
+
+/**
+ * enable_ercr_checking - enable PCIe ECRC checking for a device
+ * @dev: the PCI device
+ *
+ * Returns 0 on success, or negative on failure.
+ */
+static int enable_ecrc_checking(struct pci_dev *dev)
+{
+ int pos;
+ u32 reg32;
+
+ if (!dev->is_pcie)
+ return -ENODEV;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+ if (!pos)
+ return -ENODEV;
+
+ pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
+ if (reg32 & PCI_ERR_CAP_ECRC_GENC)
+ reg32 |= PCI_ERR_CAP_ECRC_GENE;
+ if (reg32 & PCI_ERR_CAP_ECRC_CHKC)
+ reg32 |= PCI_ERR_CAP_ECRC_CHKE;
+ pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);
+
+ return 0;
+}
+
+/**
+ * disable_ercr_checking - disables PCIe ECRC checking for a device
+ * @dev: the PCI device
+ *
+ * Returns 0 on success, or negative on failure.
+ */
+static int disable_ecrc_checking(struct pci_dev *dev)
+{
+ int pos;
+ u32 reg32;
+
+ if (!dev->is_pcie)
+ return -ENODEV;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+ if (!pos)
+ return -ENODEV;
+
+ pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
+ reg32 &= ~(PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
+ pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);
+
+ return 0;
+}
+
+/**
+ * pcie_set_ecrc_checking - set/unset PCIe ECRC checking for a device based on global policy
+ * @dev: the PCI device
+ */
+void pcie_set_ecrc_checking(struct pci_dev *dev)
+{
+ switch (ecrc_policy) {
+ case ECRC_POLICY_DEFAULT:
+ return;
+ case ECRC_POLICY_OFF:
+ disable_ecrc_checking(dev);
+ break;
+ case ECRC_POLICY_ON:
+ enable_ecrc_checking(dev);;
+ break;
+ default:
+ return;
+ }
+}
+
+/**
+ * pcie_ecrc_get_policy - parse kernel command-line ecrc option
+ */
+void pcie_ecrc_get_policy(char *str)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(ecrc_policy_str); i++)
+ if (!strncmp(str, ecrc_policy_str[i],
+ strlen(ecrc_policy_str[i])))
+ break;
+ if (i >= ARRAY_SIZE(ecrc_policy_str))
+ return;
+
+ ecrc_policy = i;
+}