arch/x86/platform/intel/iosf_mbi.c - kernel/bruno - Git at Google

 /*
  * 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
 #define PCI_DEVICE_ID_TANGIER		0x1170

 static struct pci_dev *mbi_pdev;
 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 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 (!d)
 		goto cleanup;

 	/* mcrx */
 	d = debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
 	if (!d)
 		goto cleanup;

 	/* mcr - initiates mailbox tranaction */
 	d = debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
 	if (!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) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_TANGIER) },
 	{ 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);
 	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");
	/*
	* 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
	#define PCI_DEVICE_ID_TANGIER 0x1170

	static struct pci_dev *mbi_pdev;
	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 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 (!d)
	goto cleanup;

	/* mcrx */
	d = debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
	if (!d)
	goto cleanup;

	/* mcr - initiates mailbox tranaction */
	d = debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
	if (!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) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_TANGIER) },
	{ 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);
	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");