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/*
* Baytrail 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 BayTrail-specific access to this interface.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include "intel_baytrail.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) | BT_MBI_ENABLE;
}
static struct pci_dev *mbi_pdev; /* one mbi device */
/* Hold lock before calling */
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,
BT_MBI_MCRX_OFFSET, mcrx);
if (result < 0)
goto iosf_mbi_read_err;
}
result = pci_write_config_dword(mbi_pdev,
BT_MBI_MCR_OFFSET, mcr);
if (result < 0)
goto iosf_mbi_read_err;
result = pci_read_config_dword(mbi_pdev,
BT_MBI_MDR_OFFSET, mdr);
if (result < 0)
goto iosf_mbi_read_err;
return 0;
iosf_mbi_read_err:
dev_err(&mbi_pdev->dev, "error: PCI config operation returned %d\n",
result);
return result;
}
/* Hold lock before calling */
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,
BT_MBI_MDR_OFFSET, mdr);
if (result < 0)
goto iosf_mbi_write_err;
if (mcrx) {
result = pci_write_config_dword(mbi_pdev,
BT_MBI_MCRX_OFFSET, mcrx);
if (result < 0)
goto iosf_mbi_write_err;
}
result = pci_write_config_dword(mbi_pdev,
BT_MBI_MCR_OFFSET, mcr);
if (result < 0)
goto iosf_mbi_write_err;
return 0;
iosf_mbi_write_err:
dev_err(&mbi_pdev->dev, "error: PCI config operation returned %d\n",
result);
return result;
}
int bt_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 */
BUG_ON(port == BT_MBI_UNIT_GFX);
mcr = iosf_mbi_form_mcr(opcode, port, offset & BT_MBI_MASK_LO);
mcrx = offset & BT_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(bt_mbi_read);
int bt_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 */
BUG_ON(port == BT_MBI_UNIT_GFX);
mcr = iosf_mbi_form_mcr(opcode, port, offset & BT_MBI_MASK_LO);
mcrx = offset & BT_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(bt_mbi_write);
int bt_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 */
BUG_ON(port == BT_MBI_UNIT_GFX);
mcr = iosf_mbi_form_mcr(opcode, port, offset & BT_MBI_MASK_LO);
mcrx = offset & BT_MBI_MASK_HI;
spin_lock_irqsave(&iosf_mbi_lock, flags);
/* Read current mdr value */
ret = iosf_mbi_pci_read_mdr(mcrx, mcr & BT_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 | BT_MBI_WR_MASK, value);
spin_unlock_irqrestore(&iosf_mbi_lock, flags);
return ret;
}
EXPORT_SYMBOL(bt_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 bt_mbi_init(void)
{
return pci_register_driver(&iosf_mbi_pci_driver);
}
static void __exit bt_mbi_exit(void)
{
pci_unregister_driver(&iosf_mbi_pci_driver);
if (mbi_pdev) {
pci_dev_put(mbi_pdev);
mbi_pdev = NULL;
}
}
module_init(bt_mbi_init);
module_exit(bt_mbi_exit);
MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
MODULE_DESCRIPTION("BayTrail Mailbox Interface accessor");
MODULE_LICENSE("GPL v2");
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