From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst
---
kernel/arch/x86/platform/intel/iosf_mbi.c | 288 ++++++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 234 insertions(+), 54 deletions(-)
diff --git a/kernel/arch/x86/platform/intel/iosf_mbi.c b/kernel/arch/x86/platform/intel/iosf_mbi.c
index 6f37a21..526f70f 100644
--- a/kernel/arch/x86/platform/intel/iosf_mbi.c
+++ b/kernel/arch/x86/platform/intel/iosf_mbi.c
@@ -1,41 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
+ * mailbox interface (MBI) to communicate with multiple devices. This
* driver implements access to this interface for those platforms that can
* enumerate the device using PCI.
*/
+#include <linux/delay.h>
#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 <linux/pm_qos.h>
+#include <linux/wait.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
+#define PCI_DEVICE_ID_INTEL_BAYTRAIL 0x0F00
+#define PCI_DEVICE_ID_INTEL_BRASWELL 0x2280
+#define PCI_DEVICE_ID_INTEL_QUARK_X1000 0x0958
+#define PCI_DEVICE_ID_INTEL_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);
+
+/**************** Generic iosf_mbi access helpers ****************/
static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset)
{
@@ -192,27 +186,227 @@
}
EXPORT_SYMBOL(iosf_mbi_available);
+/*
+ **************** P-Unit/kernel shared I2C bus arbritration ****************
+ *
+ * Some Bay Trail and Cherry Trail devices have the P-Unit and us (the kernel)
+ * share a single I2C bus to the PMIC. Below are helpers to arbitrate the
+ * accesses between the kernel and the P-Unit.
+ *
+ * See arch/x86/include/asm/iosf_mbi.h for kernel-doc text for each function.
+ */
+
+#define SEMAPHORE_TIMEOUT 500
+#define PUNIT_SEMAPHORE_BYT 0x7
+#define PUNIT_SEMAPHORE_CHT 0x10e
+#define PUNIT_SEMAPHORE_BIT BIT(0)
+#define PUNIT_SEMAPHORE_ACQUIRE BIT(1)
+
+static DEFINE_MUTEX(iosf_mbi_pmic_access_mutex);
+static BLOCKING_NOTIFIER_HEAD(iosf_mbi_pmic_bus_access_notifier);
+static DECLARE_WAIT_QUEUE_HEAD(iosf_mbi_pmic_access_waitq);
+static u32 iosf_mbi_pmic_punit_access_count;
+static u32 iosf_mbi_pmic_i2c_access_count;
+static u32 iosf_mbi_sem_address;
+static unsigned long iosf_mbi_sem_acquired;
+static struct pm_qos_request iosf_mbi_pm_qos;
+
void iosf_mbi_punit_acquire(void)
{
- mutex_lock(&iosf_mbi_punit_mutex);
+ /* Wait for any I2C PMIC accesses from in kernel drivers to finish. */
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+ while (iosf_mbi_pmic_i2c_access_count != 0) {
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
+ wait_event(iosf_mbi_pmic_access_waitq,
+ iosf_mbi_pmic_i2c_access_count == 0);
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+ }
+ /*
+ * We do not need to do anything to allow the PUNIT to safely access
+ * the PMIC, other then block in kernel accesses to the PMIC.
+ */
+ iosf_mbi_pmic_punit_access_count++;
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
}
EXPORT_SYMBOL(iosf_mbi_punit_acquire);
void iosf_mbi_punit_release(void)
{
- mutex_unlock(&iosf_mbi_punit_mutex);
+ bool do_wakeup;
+
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+ iosf_mbi_pmic_punit_access_count--;
+ do_wakeup = iosf_mbi_pmic_punit_access_count == 0;
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
+
+ if (do_wakeup)
+ wake_up(&iosf_mbi_pmic_access_waitq);
}
EXPORT_SYMBOL(iosf_mbi_punit_release);
+
+static int iosf_mbi_get_sem(u32 *sem)
+{
+ int ret;
+
+ ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ,
+ iosf_mbi_sem_address, sem);
+ if (ret) {
+ dev_err(&mbi_pdev->dev, "Error P-Unit semaphore read failed\n");
+ return ret;
+ }
+
+ *sem &= PUNIT_SEMAPHORE_BIT;
+ return 0;
+}
+
+static void iosf_mbi_reset_semaphore(void)
+{
+ if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ,
+ iosf_mbi_sem_address, 0, PUNIT_SEMAPHORE_BIT))
+ dev_err(&mbi_pdev->dev, "Error P-Unit semaphore reset failed\n");
+
+ cpu_latency_qos_update_request(&iosf_mbi_pm_qos, PM_QOS_DEFAULT_VALUE);
+
+ blocking_notifier_call_chain(&iosf_mbi_pmic_bus_access_notifier,
+ MBI_PMIC_BUS_ACCESS_END, NULL);
+}
+
+/*
+ * This function blocks P-Unit accesses to the PMIC I2C bus, so that kernel
+ * I2C code, such as e.g. a fuel-gauge driver, can access it safely.
+ *
+ * This function may be called by I2C controller code while an I2C driver has
+ * already blocked P-Unit accesses because it wants them blocked over multiple
+ * i2c-transfers, for e.g. read-modify-write of an I2C client register.
+ *
+ * To allow safe PMIC i2c bus accesses this function takes the following steps:
+ *
+ * 1) Some code sends request to the P-Unit which make it access the PMIC
+ * I2C bus. Testing has shown that the P-Unit does not check its internal
+ * PMIC bus semaphore for these requests. Callers of these requests call
+ * iosf_mbi_punit_acquire()/_release() around their P-Unit accesses, these
+ * functions increase/decrease iosf_mbi_pmic_punit_access_count, so first
+ * we wait for iosf_mbi_pmic_punit_access_count to become 0.
+ *
+ * 2) Check iosf_mbi_pmic_i2c_access_count, if access has already
+ * been blocked by another caller, we only need to increment
+ * iosf_mbi_pmic_i2c_access_count and we can skip the other steps.
+ *
+ * 3) Some code makes such P-Unit requests from atomic contexts where it
+ * cannot call iosf_mbi_punit_acquire() as that may sleep.
+ * As the second step we call a notifier chain which allows any code
+ * needing P-Unit resources from atomic context to acquire them before
+ * we take control over the PMIC I2C bus.
+ *
+ * 4) When CPU cores enter C6 or C7 the P-Unit needs to talk to the PMIC
+ * if this happens while the kernel itself is accessing the PMIC I2C bus
+ * the SoC hangs.
+ * As the third step we call cpu_latency_qos_update_request() to disallow the
+ * CPU to enter C6 or C7.
+ *
+ * 5) The P-Unit has a PMIC bus semaphore which we can request to stop
+ * autonomous P-Unit tasks from accessing the PMIC I2C bus while we hold it.
+ * As the fourth and final step we request this semaphore and wait for our
+ * request to be acknowledged.
+ */
+int iosf_mbi_block_punit_i2c_access(void)
+{
+ unsigned long start, end;
+ int ret = 0;
+ u32 sem;
+
+ if (WARN_ON(!mbi_pdev || !iosf_mbi_sem_address))
+ return -ENXIO;
+
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+
+ while (iosf_mbi_pmic_punit_access_count != 0) {
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
+ wait_event(iosf_mbi_pmic_access_waitq,
+ iosf_mbi_pmic_punit_access_count == 0);
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+ }
+
+ if (iosf_mbi_pmic_i2c_access_count > 0)
+ goto success;
+
+ blocking_notifier_call_chain(&iosf_mbi_pmic_bus_access_notifier,
+ MBI_PMIC_BUS_ACCESS_BEGIN, NULL);
+
+ /*
+ * Disallow the CPU to enter C6 or C7 state, entering these states
+ * requires the P-Unit to talk to the PMIC and if this happens while
+ * we're holding the semaphore, the SoC hangs.
+ */
+ cpu_latency_qos_update_request(&iosf_mbi_pm_qos, 0);
+
+ /* host driver writes to side band semaphore register */
+ ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE,
+ iosf_mbi_sem_address, PUNIT_SEMAPHORE_ACQUIRE);
+ if (ret) {
+ dev_err(&mbi_pdev->dev, "Error P-Unit semaphore request failed\n");
+ goto error;
+ }
+
+ /* host driver waits for bit 0 to be set in semaphore register */
+ start = jiffies;
+ end = start + msecs_to_jiffies(SEMAPHORE_TIMEOUT);
+ do {
+ ret = iosf_mbi_get_sem(&sem);
+ if (!ret && sem) {
+ iosf_mbi_sem_acquired = jiffies;
+ dev_dbg(&mbi_pdev->dev, "P-Unit semaphore acquired after %ums\n",
+ jiffies_to_msecs(jiffies - start));
+ goto success;
+ }
+
+ usleep_range(1000, 2000);
+ } while (time_before(jiffies, end));
+
+ ret = -ETIMEDOUT;
+ dev_err(&mbi_pdev->dev, "Error P-Unit semaphore timed out, resetting\n");
+error:
+ iosf_mbi_reset_semaphore();
+ if (!iosf_mbi_get_sem(&sem))
+ dev_err(&mbi_pdev->dev, "P-Unit semaphore: %d\n", sem);
+success:
+ if (!WARN_ON(ret))
+ iosf_mbi_pmic_i2c_access_count++;
+
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_block_punit_i2c_access);
+
+void iosf_mbi_unblock_punit_i2c_access(void)
+{
+ bool do_wakeup = false;
+
+ mutex_lock(&iosf_mbi_pmic_access_mutex);
+ iosf_mbi_pmic_i2c_access_count--;
+ if (iosf_mbi_pmic_i2c_access_count == 0) {
+ iosf_mbi_reset_semaphore();
+ dev_dbg(&mbi_pdev->dev, "punit semaphore held for %ums\n",
+ jiffies_to_msecs(jiffies - iosf_mbi_sem_acquired));
+ do_wakeup = true;
+ }
+ mutex_unlock(&iosf_mbi_pmic_access_mutex);
+
+ if (do_wakeup)
+ wake_up(&iosf_mbi_pmic_access_waitq);
+}
+EXPORT_SYMBOL(iosf_mbi_unblock_punit_i2c_access);
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);
+ iosf_mbi_punit_acquire();
ret = blocking_notifier_chain_register(
&iosf_mbi_pmic_bus_access_notifier, nb);
- mutex_unlock(&iosf_mbi_punit_mutex);
+ iosf_mbi_punit_release();
return ret;
}
@@ -233,26 +427,21 @@
int ret;
/* Wait for the bus to go inactive before unregistering */
- mutex_lock(&iosf_mbi_punit_mutex);
+ iosf_mbi_punit_acquire();
ret = iosf_mbi_unregister_pmic_bus_access_notifier_unlocked(nb);
- mutex_unlock(&iosf_mbi_punit_mutex);
+ iosf_mbi_punit_release();
return ret;
}
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);
-}
-EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain);
-
void iosf_mbi_assert_punit_acquired(void)
{
- WARN_ON(!mutex_is_locked(&iosf_mbi_punit_mutex));
+ WARN_ON(iosf_mbi_pmic_punit_access_count == 0);
}
EXPORT_SYMBOL(iosf_mbi_assert_punit_acquired);
+
+/**************** iosf_mbi debug code ****************/
#ifdef CONFIG_IOSF_MBI_DEBUG
static u32 dbg_mdr;
@@ -296,31 +485,16 @@
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;
+ debugfs_create_x32("mdr", 0660, iosf_dbg, &dbg_mdr);
/* mcrx */
- d = debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
- if (!d)
- goto cleanup;
+ debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
/* 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);
+ debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
}
static void iosf_debugfs_init(void)
@@ -338,7 +512,7 @@
#endif /* CONFIG_IOSF_MBI_DEBUG */
static int iosf_mbi_probe(struct pci_dev *pdev,
- const struct pci_device_id *unused)
+ const struct pci_device_id *dev_id)
{
int ret;
@@ -349,14 +523,16 @@
}
mbi_pdev = pci_dev_get(pdev);
+ iosf_mbi_sem_address = dev_id->driver_data;
+
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) },
+ { PCI_DEVICE_DATA(INTEL, BAYTRAIL, PUNIT_SEMAPHORE_BYT) },
+ { PCI_DEVICE_DATA(INTEL, BRASWELL, PUNIT_SEMAPHORE_CHT) },
+ { PCI_DEVICE_DATA(INTEL, QUARK_X1000, 0) },
+ { PCI_DEVICE_DATA(INTEL, TANGIER, 0) },
{ 0, },
};
MODULE_DEVICE_TABLE(pci, iosf_mbi_pci_ids);
@@ -371,6 +547,8 @@
{
iosf_debugfs_init();
+ cpu_latency_qos_add_request(&iosf_mbi_pm_qos, PM_QOS_DEFAULT_VALUE);
+
return pci_register_driver(&iosf_mbi_pci_driver);
}
@@ -381,6 +559,8 @@
pci_unregister_driver(&iosf_mbi_pci_driver);
pci_dev_put(mbi_pdev);
mbi_pdev = NULL;
+
+ cpu_latency_qos_remove_request(&iosf_mbi_pm_qos);
}
module_init(iosf_mbi_init);
--
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