diff options
| -rw-r--r-- | Documentation/devicetree/bindings/input/input-reset.txt | 33 | ||||
| -rw-r--r-- | drivers/tty/sysrq.c | 42 |
2 files changed, 75 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/input/input-reset.txt b/Documentation/devicetree/bindings/input/input-reset.txt new file mode 100644 index 000000000000..2bb2626fdb78 --- /dev/null +++ b/Documentation/devicetree/bindings/input/input-reset.txt @@ -0,0 +1,33 @@ +Input: sysrq reset sequence + +A simple binding to represent a set of keys as described in +include/uapi/linux/input.h. This is to communicate a sequence of keys to the +sysrq driver. Upon holding the keys for a specified amount of time (if +specified) the system is sync'ed and reset. + +Key sequences are global to the system but all the keys in a set must be coming +from the same input device. + +The /chosen node should contain a 'linux,sysrq-reset-seq' child node to define +a set of keys. + +Required property: +sysrq-reset-seq: array of Linux keycodes, one keycode per cell. + +Optional property: +timeout-ms: duration keys must be pressed together in milliseconds before +generating a sysrq. If omitted the system is rebooted immediately when a valid +sequence has been recognized. + +Example: + + chosen { + linux,sysrq-reset-seq { + keyset = <0x03 + 0x04 + 0x0a>; + timeout-ms = <3000>; + }; + }; + +Would represent KEY_2, KEY_3 and KEY_9. diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 55ba46f6207d..749dae8c3489 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -45,6 +45,7 @@ #include <linux/moduleparam.h> #include <linux/jiffies.h> #include <linux/syscalls.h> +#include <linux/of.h> #include <asm/ptrace.h> #include <asm/irq_regs.h> @@ -681,6 +682,40 @@ static void sysrq_detect_reset_sequence(struct sysrq_state *state, } } +#ifdef CONFIG_OF +static void sysrq_of_get_keyreset_config(void) +{ + u32 key; + struct device_node *np; + struct property *prop; + const __be32 *p; + + np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); + if (!np) { + pr_debug("No sysrq node found"); + return; + } + + /* Reset in case a __weak definition was present */ + sysrq_reset_seq_len = 0; + + of_property_for_each_u32(np, "keyset", prop, p, key) { + if (key == KEY_RESERVED || key > KEY_MAX || + sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) + break; + + sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; + } + + /* Get reset timeout if any. */ + of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); +} +#else +static void sysrq_of_get_keyreset_config(void) +{ +} +#endif + static void sysrq_reinject_alt_sysrq(struct work_struct *work) { struct sysrq_state *sysrq = @@ -914,6 +949,7 @@ static inline void sysrq_register_handler(void) int error; int i; + /* First check if a __weak interface was instantiated. */ for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) { key = platform_sysrq_reset_seq[i]; if (key == KEY_RESERVED || key > KEY_MAX) @@ -922,6 +958,12 @@ static inline void sysrq_register_handler(void) sysrq_reset_seq[sysrq_reset_seq_len++] = key; } + /* + * DT configuration takes precedence over anything that would + * have been defined via the __weak interface. + */ + sysrq_of_get_keyreset_config(); + error = input_register_handler(&sysrq_handler); if (error) pr_err("Failed to register input handler, error %d", error); |