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Diffstat (limited to 'arch/x86/kernel/iosf_mbi.c')
-rw-r--r--arch/x86/kernel/iosf_mbi.c226
1 files changed, 226 insertions, 0 deletions
diff --git a/arch/x86/kernel/iosf_mbi.c b/arch/x86/kernel/iosf_mbi.c
new file mode 100644
index 000000000000..c3aae6672843
--- /dev/null
+++ b/arch/x86/kernel/iosf_mbi.c
@@ -0,0 +1,226 @@
+/*
+ * IOSF-SB MailBox Interface Driver
+ * Copyright (c) 2013, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ *
+ * The IOSF-SB is a fabric bus available on Atom based SOC's that uses a
+ * mailbox interface (MBI) to communicate with mutiple devices. This
+ * driver implements access to this interface for those platforms that can
+ * enumerate the device using PCI.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/pci.h>
+
+#include <asm/iosf_mbi.h>
+
+static DEFINE_SPINLOCK(iosf_mbi_lock);
+
+static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset)
+{
+ return (op << 24) | (port << 16) | (offset << 8) | MBI_ENABLE;
+}
+
+static struct pci_dev *mbi_pdev; /* one mbi device */
+
+static int iosf_mbi_pci_read_mdr(u32 mcrx, u32 mcr, u32 *mdr)
+{
+ int result;
+
+ if (!mbi_pdev)
+ return -ENODEV;
+
+ if (mcrx) {
+ result = pci_write_config_dword(mbi_pdev, MBI_MCRX_OFFSET,
+ mcrx);
+ if (result < 0)
+ goto fail_read;
+ }
+
+ result = pci_write_config_dword(mbi_pdev, MBI_MCR_OFFSET, mcr);
+ if (result < 0)
+ goto fail_read;
+
+ result = pci_read_config_dword(mbi_pdev, MBI_MDR_OFFSET, mdr);
+ if (result < 0)
+ goto fail_read;
+
+ return 0;
+
+fail_read:
+ dev_err(&mbi_pdev->dev, "PCI config access failed with %d\n", result);
+ return result;
+}
+
+static int iosf_mbi_pci_write_mdr(u32 mcrx, u32 mcr, u32 mdr)
+{
+ int result;
+
+ if (!mbi_pdev)
+ return -ENODEV;
+
+ result = pci_write_config_dword(mbi_pdev, MBI_MDR_OFFSET, mdr);
+ if (result < 0)
+ goto fail_write;
+
+ if (mcrx) {
+ result = pci_write_config_dword(mbi_pdev, MBI_MCRX_OFFSET,
+ mcrx);
+ if (result < 0)
+ goto fail_write;
+ }
+
+ result = pci_write_config_dword(mbi_pdev, MBI_MCR_OFFSET, mcr);
+ if (result < 0)
+ goto fail_write;
+
+ return 0;
+
+fail_write:
+ dev_err(&mbi_pdev->dev, "PCI config access failed with %d\n", result);
+ return result;
+}
+
+int iosf_mbi_read(u8 port, u8 opcode, u32 offset, u32 *mdr)
+{
+ u32 mcr, mcrx;
+ unsigned long flags;
+ int ret;
+
+ /*Access to the GFX unit is handled by GPU code */
+ if (port == BT_MBI_UNIT_GFX) {
+ WARN_ON(1);
+ return -EPERM;
+ }
+
+ mcr = iosf_mbi_form_mcr(opcode, port, offset & MBI_MASK_LO);
+ mcrx = offset & MBI_MASK_HI;
+
+ spin_lock_irqsave(&iosf_mbi_lock, flags);
+ ret = iosf_mbi_pci_read_mdr(mcrx, mcr, mdr);
+ spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_read);
+
+int iosf_mbi_write(u8 port, u8 opcode, u32 offset, u32 mdr)
+{
+ u32 mcr, mcrx;
+ unsigned long flags;
+ int ret;
+
+ /*Access to the GFX unit is handled by GPU code */
+ if (port == BT_MBI_UNIT_GFX) {
+ WARN_ON(1);
+ return -EPERM;
+ }
+
+ mcr = iosf_mbi_form_mcr(opcode, port, offset & MBI_MASK_LO);
+ mcrx = offset & MBI_MASK_HI;
+
+ spin_lock_irqsave(&iosf_mbi_lock, flags);
+ ret = iosf_mbi_pci_write_mdr(mcrx, mcr, mdr);
+ spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_write);
+
+int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask)
+{
+ u32 mcr, mcrx;
+ u32 value;
+ unsigned long flags;
+ int ret;
+
+ /*Access to the GFX unit is handled by GPU code */
+ if (port == BT_MBI_UNIT_GFX) {
+ WARN_ON(1);
+ return -EPERM;
+ }
+
+ mcr = iosf_mbi_form_mcr(opcode, port, offset & MBI_MASK_LO);
+ mcrx = offset & MBI_MASK_HI;
+
+ spin_lock_irqsave(&iosf_mbi_lock, flags);
+
+ /* Read current mdr value */
+ ret = iosf_mbi_pci_read_mdr(mcrx, mcr & MBI_RD_MASK, &value);
+ if (ret < 0) {
+ spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+ return ret;
+ }
+
+ /* Apply mask */
+ value &= ~mask;
+ mdr &= mask;
+ value |= mdr;
+
+ /* Write back */
+ ret = iosf_mbi_pci_write_mdr(mcrx, mcr | MBI_WR_MASK, value);
+
+ spin_unlock_irqrestore(&iosf_mbi_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_modify);
+
+static int iosf_mbi_probe(struct pci_dev *pdev,
+ const struct pci_device_id *unused)
+{
+ int ret;
+
+ ret = pci_enable_device(pdev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "error: could not enable device\n");
+ return ret;
+ }
+
+ mbi_pdev = pci_dev_get(pdev);
+ return 0;
+}
+
+static DEFINE_PCI_DEVICE_TABLE(iosf_mbi_pci_ids) = {
+ { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0F00) },
+ { 0, },
+};
+MODULE_DEVICE_TABLE(pci, iosf_mbi_pci_ids);
+
+static struct pci_driver iosf_mbi_pci_driver = {
+ .name = "iosf_mbi_pci",
+ .probe = iosf_mbi_probe,
+ .id_table = iosf_mbi_pci_ids,
+};
+
+static int __init iosf_mbi_init(void)
+{
+ return pci_register_driver(&iosf_mbi_pci_driver);
+}
+
+static void __exit iosf_mbi_exit(void)
+{
+ pci_unregister_driver(&iosf_mbi_pci_driver);
+ if (mbi_pdev) {
+ pci_dev_put(mbi_pdev);
+ mbi_pdev = NULL;
+ }
+}
+
+module_init(iosf_mbi_init);
+module_exit(iosf_mbi_exit);
+
+MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
+MODULE_DESCRIPTION("IOSF Mailbox Interface accessor");
+MODULE_LICENSE("GPL v2");