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commitaa49c90894upstream. Sincebae1d3a05a, i2c transfers are non-atomic if preemption is disabled. However, non-atomic i2c transfers require preemption (e.g. in wait_for_completion() while waiting for the DMA). panic() calls preempt_disable_notrace() before calling emergency_restart(). Therefore, if an i2c device is used for the restart, the xfer should be atomic. This avoids warnings like: [ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0 [ 12.676926] Voluntary context switch within RCU read-side critical section! ... [ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114 [ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70 ... [ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58 [ 13.001050] machine_restart from panic+0x2a8/0x32c Use !preemptible() instead, which is basically the same check as pre-v5.2. Fixes:bae1d3a05a("i2c: core: remove use of in_atomic()") Cc: stable@vger.kernel.org # v5.2+ Suggested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Acked-by: Wolfram Sang <wsa@kernel.org> Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Tested-by: Nishanth Menon <nm@ti.com> Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com> Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-2-18699d5dcd76@skidata.com Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
98 lines
2.8 KiB
C
98 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* i2c-core.h - interfaces internal to the I2C framework
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*/
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#include <linux/rwsem.h>
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struct i2c_devinfo {
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struct list_head list;
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int busnum;
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struct i2c_board_info board_info;
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};
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/* board_lock protects board_list and first_dynamic_bus_num.
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* only i2c core components are allowed to use these symbols.
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*/
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extern struct rw_semaphore __i2c_board_lock;
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extern struct list_head __i2c_board_list;
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extern int __i2c_first_dynamic_bus_num;
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int i2c_check_7bit_addr_validity_strict(unsigned short addr);
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int i2c_dev_irq_from_resources(const struct resource *resources,
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unsigned int num_resources);
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/*
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* We only allow atomic transfers for very late communication, e.g. to access a
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* PMIC when powering down. Atomic transfers are a corner case and not for
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* generic use!
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*/
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static inline bool i2c_in_atomic_xfer_mode(void)
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{
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return system_state > SYSTEM_RUNNING && !preemptible();
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}
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static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
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{
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int ret = 0;
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if (i2c_in_atomic_xfer_mode()) {
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WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic,
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"No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev));
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ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
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} else {
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i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
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}
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return ret;
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}
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static inline int __i2c_check_suspended(struct i2c_adapter *adap)
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{
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if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) {
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if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags))
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dev_WARN(&adap->dev, "Transfer while suspended\n");
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return -ESHUTDOWN;
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}
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return 0;
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}
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#ifdef CONFIG_ACPI
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void i2c_acpi_register_devices(struct i2c_adapter *adap);
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int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable);
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#else /* CONFIG_ACPI */
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static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
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static inline int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
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{
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return 0;
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}
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#endif /* CONFIG_ACPI */
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extern struct notifier_block i2c_acpi_notifier;
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#ifdef CONFIG_ACPI_I2C_OPREGION
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int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
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void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
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#else /* CONFIG_ACPI_I2C_OPREGION */
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static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
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static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
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#endif /* CONFIG_ACPI_I2C_OPREGION */
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#ifdef CONFIG_OF
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void of_i2c_register_devices(struct i2c_adapter *adap);
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#else
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static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
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#endif
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extern struct notifier_block i2c_of_notifier;
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#if IS_ENABLED(CONFIG_I2C_SMBUS)
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int i2c_setup_smbus_alert(struct i2c_adapter *adap);
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#else
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static inline int i2c_setup_smbus_alert(struct i2c_adapter *adap)
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{
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return 0;
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}
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#endif
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