From c4c7eac8ee78d896635ce05d7a1c3f813fcbe24c Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 15 May 2023 16:14:29 -0700 Subject: Input: libps2 - introduce common interrupt handler Instead of exposing inner workings of libps2 to drivers such as atkbd and psmouse, have them define pre-receive and receive callbacks, and provide a common handler that can be used with underlying serio port. While at this add kerneldoc to the module. Link: https://lore.kernel.org/r/ZGK81cxqjr/KS1kA@google.com Signed-off-by: Dmitry Torokhov --- drivers/input/serio/libps2.c | 226 ++++++++++++++++++++++++++++++------------- 1 file changed, 161 insertions(+), 65 deletions(-) (limited to 'drivers/input/serio') diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c index 09eb605364bb..7c5fc853072a 100644 --- a/drivers/input/serio/libps2.c +++ b/drivers/input/serio/libps2.c @@ -19,9 +19,22 @@ #define DRIVER_DESC "PS/2 driver library" -MODULE_AUTHOR("Dmitry Torokhov "); -MODULE_DESCRIPTION("PS/2 driver library"); -MODULE_LICENSE("GPL"); +#define PS2_CMD_SETSCALE11 0x00e6 +#define PS2_CMD_SETRES 0x10e8 +#define PS2_CMD_GETID 0x02f2 +#define PS2_CMD_RESET_BAT 0x02ff + +#define PS2_RET_BAT 0xaa +#define PS2_RET_ID 0x00 +#define PS2_RET_ACK 0xfa +#define PS2_RET_NAK 0xfe +#define PS2_RET_ERR 0xfc + +#define PS2_FLAG_ACK BIT(0) /* Waiting for ACK/NAK */ +#define PS2_FLAG_CMD BIT(1) /* Waiting for a command to finish */ +#define PS2_FLAG_CMD1 BIT(2) /* Waiting for the first byte of command response */ +#define PS2_FLAG_WAITID BIT(3) /* Command executing is GET ID */ +#define PS2_FLAG_NAK BIT(4) /* Last transmission was NAKed */ static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout, unsigned int max_attempts) @@ -76,14 +89,17 @@ static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte, return error; } -/* - * ps2_sendbyte() sends a byte to the device and waits for acknowledge. - * It doesn't handle retransmission, the caller is expected to handle +/** + * ps2_sendbyte - sends a byte to the device and wait for acknowledgement + * @ps2dev: a PS/2 device to send the data to + * @byte: data to be sent to the device + * @timeout: timeout for sending the data and receiving an acknowledge + * + * The function doesn't handle retransmission, the caller is expected to handle * it when needed. * * ps2_sendbyte() can only be called from a process context. */ - int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout) { int retval; @@ -99,6 +115,13 @@ int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout) } EXPORT_SYMBOL(ps2_sendbyte); +/** + * ps2_begin_command - mark beginning of execution of a complex command + * @ps2dev: a PS/2 device executing the command + * + * Serializes a complex/compound command. Once command is finished + * ps2_end_command() should be called. + */ void ps2_begin_command(struct ps2dev *ps2dev) { struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; @@ -107,6 +130,10 @@ void ps2_begin_command(struct ps2dev *ps2dev) } EXPORT_SYMBOL(ps2_begin_command); +/** + * ps2_end_command - mark end of execution of a complex command + * @ps2dev: a PS/2 device executing the command + */ void ps2_end_command(struct ps2dev *ps2dev) { struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex; @@ -115,11 +142,13 @@ void ps2_end_command(struct ps2dev *ps2dev) } EXPORT_SYMBOL(ps2_end_command); -/* - * ps2_drain() waits for device to transmit requested number of bytes - * and discards them. +/** + * ps2_drain - waits for device to transmit requested number of bytes + * and discards them + * @ps2dev: the PS/2 device that should be drained + * @maxbytes: maximum number of bytes to be drained + * @timeout: time to drain the device */ - void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout) { if (maxbytes > sizeof(ps2dev->cmdbuf)) { @@ -142,11 +171,11 @@ void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout) } EXPORT_SYMBOL(ps2_drain); -/* - * ps2_is_keyboard_id() checks received ID byte against the list of - * known keyboard IDs. +/** + * ps2_is_keyboard_id - checks received ID byte against the list of + * known keyboard IDs + * @id_byte: data byte that should be checked */ - bool ps2_is_keyboard_id(u8 id_byte) { static const u8 keyboard_ids[] = { @@ -167,7 +196,6 @@ EXPORT_SYMBOL(ps2_is_keyboard_id); * response and tries to reduce remaining timeout to speed up command * completion. */ - static int ps2_adjust_timeout(struct ps2dev *ps2dev, unsigned int command, unsigned int timeout) { @@ -217,13 +245,19 @@ static int ps2_adjust_timeout(struct ps2dev *ps2dev, return timeout; } -/* - * ps2_command() sends a command and its parameters to the mouse, - * then waits for the response and puts it in the param array. +/** + * __ps2_command - send a command to PS/2 device + * @ps2dev: the PS/2 device that should execute the command + * @param: a buffer containing parameters to be sent along with the command, + * or place where the results of the command execution will be deposited, + * or both + * @command: command word that encodes the command itself, as well as number of + * additional parameter bytes that should be sent to the device and expected + * length of the command response * - * ps2_command() can only be called from a process context + * Not serialized. Callers should use ps2_begin_command() and ps2_end_command() + * to ensure proper serialization for complex commands. */ - int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) { unsigned int timeout; @@ -327,6 +361,20 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) } EXPORT_SYMBOL(__ps2_command); +/** + * ps2_command - send a command to PS/2 device + * @ps2dev: the PS/2 device that should execute the command + * @param: a buffer containing parameters to be sent along with the command, + * or place where the results of the command execution will be deposited, + * or both + * @command: command word that encodes the command itself, as well as number of + * additional parameter bytes that should be sent to the device and expected + * length of the command response + * + * Note: ps2_command() serializes the command execution so that only one + * command can be executed at a time for either individual port or the entire + * 8042 controller. + */ int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) { int rc; @@ -339,14 +387,16 @@ int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) } EXPORT_SYMBOL(ps2_command); -/* - * ps2_sliced_command() sends an extended PS/2 command to the mouse - * using sliced syntax, understood by advanced devices, such as Logitech - * or Synaptics touchpads. The command is encoded as: +/** + * ps2_sliced_command - sends an extended PS/2 command to a mouse + * @ps2dev: the PS/2 device that should execute the command + * @command: command byte + * + * The command is sent using "sliced" syntax understood by advanced devices, + * such as Logitech or Synaptics touchpads. The command is encoded as: * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu * is the command. */ - int ps2_sliced_command(struct ps2dev *ps2dev, u8 command) { int i; @@ -372,12 +422,22 @@ out: } EXPORT_SYMBOL(ps2_sliced_command); -/* - * ps2_init() initializes ps2dev structure +/** + * ps2_init - initializes ps2dev structure + * @ps2dev: structure to be initialized + * @serio: serio port associated with the PS/2 device + * @pre_receive_handler: validation handler to check basic communication state + * @receive_handler: main protocol handler + * + * Prepares ps2dev structure for use in drivers for PS/2 devices. */ - -void ps2_init(struct ps2dev *ps2dev, struct serio *serio) +void ps2_init(struct ps2dev *ps2dev, struct serio *serio, + ps2_pre_receive_handler_t pre_receive_handler, + ps2_receive_handler_t receive_handler) { + ps2dev->pre_receive_handler = pre_receive_handler; + ps2dev->receive_handler = receive_handler; + mutex_init(&ps2dev->cmd_mutex); lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth); init_waitqueue_head(&ps2dev->wait); @@ -387,11 +447,35 @@ void ps2_init(struct ps2dev *ps2dev, struct serio *serio) EXPORT_SYMBOL(ps2_init); /* - * ps2_handle_ack() is supposed to be used in interrupt handler - * to properly process ACK/NAK of a command from a PS/2 device. + * ps2_handle_response() stores device's response to a command and notifies + * the process waiting for completion of the command. Note that there is a + * distinction between waiting for the first byte of the response, and + * waiting for subsequent bytes. It is done so that callers could shorten + * timeouts once first byte of response is received. */ +static void ps2_handle_response(struct ps2dev *ps2dev, u8 data) +{ + if (ps2dev->cmdcnt) + ps2dev->cmdbuf[--ps2dev->cmdcnt] = data; -bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data) + if (ps2dev->flags & PS2_FLAG_CMD1) { + ps2dev->flags &= ~PS2_FLAG_CMD1; + if (ps2dev->cmdcnt) + wake_up(&ps2dev->wait); + } + + if (!ps2dev->cmdcnt) { + ps2dev->flags &= ~PS2_FLAG_CMD; + wake_up(&ps2dev->wait); + } +} + +/* + * ps2_handle_ack() processes ACK/NAK of a command from a PS/2 device, + * possibly applying workarounds for mice not acknowledging the "get ID" + * command. + */ +static void ps2_handle_ack(struct ps2dev *ps2dev, u8 data) { switch (data) { case PS2_RET_ACK: @@ -436,53 +520,25 @@ bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data) */ dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data); ps2dev->flags &= ~PS2_FLAG_WAITID; - return true; + return; } if (!ps2dev->nak) ps2dev->flags &= ~PS2_FLAG_NAK; ps2dev->flags &= ~PS2_FLAG_ACK; - wake_up(&ps2dev->wait); if (!ps2dev->nak && data != PS2_RET_ACK) ps2_handle_response(ps2dev, data); - - return true; -} -EXPORT_SYMBOL(ps2_handle_ack); - -/* - * ps2_handle_response() is supposed to be used in interrupt handler - * to properly store device's response to a command and notify process - * waiting for completion of the command. - */ - -bool ps2_handle_response(struct ps2dev *ps2dev, u8 data) -{ - if (ps2dev->cmdcnt) - ps2dev->cmdbuf[--ps2dev->cmdcnt] = data; - - if (ps2dev->flags & PS2_FLAG_CMD1) { - ps2dev->flags &= ~PS2_FLAG_CMD1; - if (ps2dev->cmdcnt) - wake_up(&ps2dev->wait); - } - - if (!ps2dev->cmdcnt) { - ps2dev->flags &= ~PS2_FLAG_CMD; + else wake_up(&ps2dev->wait); - } - - return true; } -EXPORT_SYMBOL(ps2_handle_response); /* * Clears state of PS/2 device after communication error by resetting majority * of flags and waking up waiters, if any. */ -void ps2_cmd_aborted(struct ps2dev *ps2dev) +static void ps2_cleanup(struct ps2dev *ps2dev) { unsigned long old_flags = ps2dev->flags; @@ -494,6 +550,46 @@ void ps2_cmd_aborted(struct ps2dev *ps2dev) if (old_flags & (PS2_FLAG_ACK | PS2_FLAG_CMD)) wake_up(&ps2dev->wait); +} +/** + * ps2_interrupt - common interrupt handler for PS/2 devices + * @serio: serio port for the device + * @data: a data byte received from the device + * @flags: flags such as %SERIO_PARITY or %SERIO_TIMEOUT indicating state of + * the data transfer + * + * ps2_interrupt() invokes pre-receive handler, optionally handles command + * acknowledgement and response from the device, and finally passes the data + * to the main protocol handler for future processing. + */ +irqreturn_t ps2_interrupt(struct serio *serio, u8 data, unsigned int flags) { + struct ps2dev *ps2dev = serio_get_drvdata(serio); + enum ps2_disposition rc; + + rc = ps2dev->pre_receive_handler(ps2dev, data, flags); + switch (rc) { + case PS2_ERROR: + ps2_cleanup(ps2dev); + break; + + case PS2_IGNORE: + break; + + case PS2_PROCESS: + if (ps2dev->flags & PS2_FLAG_ACK) + ps2_handle_ack(ps2dev, data); + else if (ps2dev->flags & PS2_FLAG_CMD) + ps2_handle_response(ps2dev, data); + else + ps2dev->receive_handler(ps2dev, data); + break; + } + + return IRQ_HANDLED; } -EXPORT_SYMBOL(ps2_cmd_aborted); +EXPORT_SYMBOL(ps2_interrupt); + +MODULE_AUTHOR("Dmitry Torokhov "); +MODULE_DESCRIPTION("PS/2 driver library"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3