linux/arch/x86/kernel/iosf_mbi.c
David E. Box ed2226bd4d x86/platform/intel/iosf: Add debugfs config option for IOSF
Makes the IOSF sideband available through debugfs. Allows
developers to experiment with using the sideband to provide
debug and analytical tools for units on the SoC.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: http://lkml.kernel.org/r/1411017231-20807-4-git-send-email-david.e.box@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 13:08:43 +02:00

329 lines
7.1 KiB
C

/*
* 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 <linux/debugfs.h>
#include <linux/capability.h>
#include <asm/iosf_mbi.h>
#define PCI_DEVICE_ID_BAYTRAIL 0x0F00
#define PCI_DEVICE_ID_BRASWELL 0x2280
#define PCI_DEVICE_ID_QUARK_X1000 0x0958
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);
bool iosf_mbi_available(void)
{
/* Mbi isn't hot-pluggable. No remove routine is provided */
return mbi_pdev;
}
EXPORT_SYMBOL(iosf_mbi_available);
#ifdef CONFIG_IOSF_MBI_DEBUG
static u32 dbg_mdr;
static u32 dbg_mcr;
static u32 dbg_mcrx;
static int mcr_get(void *data, u64 *val)
{
*val = *(u32 *)data;
return 0;
}
static int mcr_set(void *data, u64 val)
{
u8 command = ((u32)val & 0xFF000000) >> 24,
port = ((u32)val & 0x00FF0000) >> 16,
offset = ((u32)val & 0x0000FF00) >> 8;
int err;
*(u32 *)data = val;
if (!capable(CAP_SYS_RAWIO))
return -EACCES;
if (command & 1u)
err = iosf_mbi_write(port,
command,
dbg_mcrx | offset,
dbg_mdr);
else
err = iosf_mbi_read(port,
command,
dbg_mcrx | offset,
&dbg_mdr);
return err;
}
DEFINE_SIMPLE_ATTRIBUTE(iosf_mcr_fops, mcr_get, mcr_set , "%llx\n");
static struct dentry *iosf_dbg;
static void iosf_sideband_debug_init(void)
{
struct dentry *d;
iosf_dbg = debugfs_create_dir("iosf_sb", NULL);
if (IS_ERR_OR_NULL(iosf_dbg))
return;
/* mdr */
d = debugfs_create_x32("mdr", 0660, iosf_dbg, &dbg_mdr);
if (IS_ERR_OR_NULL(d))
goto cleanup;
/* mcrx */
debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
if (IS_ERR_OR_NULL(d))
goto cleanup;
/* mcr - initiates mailbox tranaction */
debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
if (IS_ERR_OR_NULL(d))
goto cleanup;
return;
cleanup:
debugfs_remove_recursive(d);
}
static void iosf_debugfs_init(void)
{
iosf_sideband_debug_init();
}
static void iosf_debugfs_remove(void)
{
debugfs_remove_recursive(iosf_dbg);
}
#else
static inline void iosf_debugfs_init(void) { }
static inline void iosf_debugfs_remove(void) { }
#endif /* CONFIG_IOSF_MBI_DEBUG */
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 const struct pci_device_id iosf_mbi_pci_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_BAYTRAIL) },
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_BRASWELL) },
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_QUARK_X1000) },
{ 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)
{
iosf_debugfs_init();
return pci_register_driver(&iosf_mbi_pci_driver);
}
static void __exit iosf_mbi_exit(void)
{
iosf_debugfs_remove();
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");