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Release 4.14 arch/x86/platform/intel/iosf_mbi.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

#define PCI_DEVICE_ID_TANGIER		0x1170


static struct pci_dev *mbi_pdev;
static DEFINE_SPINLOCK(iosf_mbi_lock);
static DEFINE_MUTEX(iosf_mbi_punit_mutex);
static BLOCKING_NOTIFIER_HEAD(iosf_mbi_pmic_bus_access_notifier);


static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset) { return (op << 24) | (port << 16) | (offset << 8) | MBI_ENABLE; }

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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; }

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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; }

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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; }

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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; }

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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; }

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EXPORT_SYMBOL(iosf_mbi_modify);
bool iosf_mbi_available(void) { /* Mbi isn't hot-pluggable. No remove routine is provided */ return mbi_pdev; }

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EXPORT_SYMBOL(iosf_mbi_available);
void iosf_mbi_punit_acquire(void) { mutex_lock(&iosf_mbi_punit_mutex); }

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EXPORT_SYMBOL(iosf_mbi_punit_acquire);
void iosf_mbi_punit_release(void) { mutex_unlock(&iosf_mbi_punit_mutex); }

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EXPORT_SYMBOL(iosf_mbi_punit_release);
int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb) { int ret; /* Wait for the bus to go inactive before registering */ mutex_lock(&iosf_mbi_punit_mutex); ret = blocking_notifier_chain_register( &iosf_mbi_pmic_bus_access_notifier, nb); mutex_unlock(&iosf_mbi_punit_mutex); return ret; }

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EXPORT_SYMBOL(iosf_mbi_register_pmic_bus_access_notifier);
int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb) { int ret; /* Wait for the bus to go inactive before unregistering */ mutex_lock(&iosf_mbi_punit_mutex); ret = blocking_notifier_chain_unregister( &iosf_mbi_pmic_bus_access_notifier, nb); mutex_unlock(&iosf_mbi_punit_mutex); return ret; }

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EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier);
int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v) { return blocking_notifier_call_chain( &iosf_mbi_pmic_bus_access_notifier, val, v); }

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EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain); #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; }

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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; }

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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); }

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static void iosf_debugfs_init(void) { iosf_sideband_debug_init(); }

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static void iosf_debugfs_remove(void) { debugfs_remove_recursive(iosf_dbg); }

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#else
static inline void iosf_debugfs_init(void) { }

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static inline void iosf_debugfs_remove(void) { }

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#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; }

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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); }

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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; }

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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");

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