diff options
Diffstat (limited to 'drivers/input/serio/libps2.c')
| -rw-r--r-- | drivers/input/serio/libps2.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c new file mode 100644 index 0000000000..6d78a1fe00 --- /dev/null +++ b/drivers/input/serio/libps2.c @@ -0,0 +1,623 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PS/2 driver library + * + * Copyright (c) 1999-2002 Vojtech Pavlik + * Copyright (c) 2004 Dmitry Torokhov + */ + + +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/input.h> +#include <linux/kmsan-checks.h> +#include <linux/serio.h> +#include <linux/i8042.h> +#include <linux/libps2.h> + +#define DRIVER_DESC "PS/2 driver library" + +#define PS2_CMD_SETSCALE11 0x00e6 +#define PS2_CMD_SETRES 0x10e8 +#define PS2_CMD_EX_SETLEDS 0x20eb +#define PS2_CMD_SETLEDS 0x10ed +#define PS2_CMD_GETID 0x02f2 +#define PS2_CMD_SETREP 0x10f3 /* Set repeat rate/set report rate */ +#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 */ +#define PS2_FLAG_PASS_NOACK BIT(5) /* Pass non-ACK byte to receive handler */ + +static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte, + unsigned int timeout, unsigned int max_attempts) + __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock) +{ + int attempt = 0; + int error; + + lockdep_assert_held(&ps2dev->serio->lock); + + do { + ps2dev->nak = 1; + ps2dev->flags |= PS2_FLAG_ACK; + + serio_continue_rx(ps2dev->serio); + + error = serio_write(ps2dev->serio, byte); + if (error) + dev_dbg(&ps2dev->serio->dev, + "failed to write %#02x: %d\n", byte, error); + else + wait_event_timeout(ps2dev->wait, + !(ps2dev->flags & PS2_FLAG_ACK), + msecs_to_jiffies(timeout)); + + serio_pause_rx(ps2dev->serio); + } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts); + + ps2dev->flags &= ~PS2_FLAG_ACK; + + if (!error) { + switch (ps2dev->nak) { + case 0: + break; + case PS2_RET_NAK: + error = -EAGAIN; + break; + case PS2_RET_ERR: + error = -EPROTO; + break; + default: + error = -EIO; + break; + } + } + + if (error || attempt > 1) + dev_dbg(&ps2dev->serio->dev, + "%02x - %d (%x), attempt %d\n", + byte, error, ps2dev->nak, attempt); + + return error; +} + +/** + * 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; + + serio_pause_rx(ps2dev->serio); + + retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1); + dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak); + + serio_continue_rx(ps2dev->serio); + + return retval; +} +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; + + mutex_lock(m); +} +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; + + mutex_unlock(m); +} +EXPORT_SYMBOL(ps2_end_command); + +/** + * 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)) { + WARN_ON(1); + maxbytes = sizeof(ps2dev->cmdbuf); + } + + ps2_begin_command(ps2dev); + + serio_pause_rx(ps2dev->serio); + ps2dev->flags = PS2_FLAG_CMD; + ps2dev->cmdcnt = maxbytes; + serio_continue_rx(ps2dev->serio); + + wait_event_timeout(ps2dev->wait, + !(ps2dev->flags & PS2_FLAG_CMD), + msecs_to_jiffies(timeout)); + + ps2_end_command(ps2dev); +} +EXPORT_SYMBOL(ps2_drain); + +/** + * 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[] = { + 0xab, /* Regular keyboards */ + 0xac, /* NCD Sun keyboard */ + 0x2b, /* Trust keyboard, translated */ + 0x5d, /* Trust keyboard */ + 0x60, /* NMB SGI keyboard, translated */ + 0x47, /* NMB SGI keyboard */ + }; + + return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL; +} +EXPORT_SYMBOL(ps2_is_keyboard_id); + +/* + * ps2_adjust_timeout() is called after receiving 1st byte of command + * 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) +{ + switch (command) { + case PS2_CMD_RESET_BAT: + /* + * Device has sent the first response byte after + * reset command, reset is thus done, so we can + * shorten the timeout. + * The next byte will come soon (keyboard) or not + * at all (mouse). + */ + if (timeout > msecs_to_jiffies(100)) + timeout = msecs_to_jiffies(100); + break; + + case PS2_CMD_GETID: + /* + * Microsoft Natural Elite keyboard responds to + * the GET ID command as it were a mouse, with + * a single byte. Fail the command so atkbd will + * use alternative probe to detect it. + */ + if (ps2dev->cmdbuf[1] == 0xaa) { + serio_pause_rx(ps2dev->serio); + ps2dev->flags = 0; + serio_continue_rx(ps2dev->serio); + timeout = 0; + } + + /* + * If device behind the port is not a keyboard there + * won't be 2nd byte of ID response. + */ + if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) { + serio_pause_rx(ps2dev->serio); + ps2dev->flags = ps2dev->cmdcnt = 0; + serio_continue_rx(ps2dev->serio); + timeout = 0; + } + break; + + default: + break; + } + + return timeout; +} + +/** + * __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 + * + * 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; + unsigned int send = (command >> 12) & 0xf; + unsigned int receive = (command >> 8) & 0xf; + int rc; + int i; + u8 send_param[16]; + + if (receive > sizeof(ps2dev->cmdbuf)) { + WARN_ON(1); + return -EINVAL; + } + + if (send && !param) { + WARN_ON(1); + return -EINVAL; + } + + memcpy(send_param, param, send); + + serio_pause_rx(ps2dev->serio); + + ps2dev->cmdcnt = receive; + + switch (command) { + case PS2_CMD_GETID: + /* + * Some mice do not ACK the "get ID" command, prepare to + * handle this. + */ + ps2dev->flags = PS2_FLAG_WAITID; + break; + + case PS2_CMD_SETLEDS: + case PS2_CMD_EX_SETLEDS: + case PS2_CMD_SETREP: + ps2dev->flags = PS2_FLAG_PASS_NOACK; + break; + + default: + ps2dev->flags = 0; + break; + } + + if (receive) { + /* Indicate that we expect response to the command. */ + ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1; + if (param) + for (i = 0; i < receive; i++) + ps2dev->cmdbuf[(receive - 1) - i] = param[i]; + } + + /* + * Some devices (Synaptics) perform the reset before + * ACKing the reset command, and so it can take a long + * time before the ACK arrives. + */ + timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200; + + rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2); + if (rc) + goto out_reset_flags; + + /* Send command parameters, if any. */ + for (i = 0; i < send; i++) { + rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2); + if (rc) + goto out_reset_flags; + } + + serio_continue_rx(ps2dev->serio); + + /* + * The reset command takes a long time to execute. + */ + timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500); + + timeout = wait_event_timeout(ps2dev->wait, + !(ps2dev->flags & PS2_FLAG_CMD1), timeout); + + if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) { + + timeout = ps2_adjust_timeout(ps2dev, command, timeout); + wait_event_timeout(ps2dev->wait, + !(ps2dev->flags & PS2_FLAG_CMD), timeout); + } + + serio_pause_rx(ps2dev->serio); + + if (param) { + for (i = 0; i < receive; i++) + param[i] = ps2dev->cmdbuf[(receive - 1) - i]; + kmsan_unpoison_memory(param, receive); + } + + if (ps2dev->cmdcnt && + (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) { + rc = -EPROTO; + goto out_reset_flags; + } + + rc = 0; + + out_reset_flags: + ps2dev->flags = 0; + serio_continue_rx(ps2dev->serio); + + dev_dbg(&ps2dev->serio->dev, + "%02x [%*ph] - %x/%08lx [%*ph]\n", + command & 0xff, send, send_param, + ps2dev->nak, ps2dev->flags, + receive, param ?: send_param); + + /* + * ps_command() handles resends itself, so do not leak -EAGAIN + * to the callers. + */ + return rc != -EAGAIN ? rc : -EPROTO; +} +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; + + ps2_begin_command(ps2dev); + rc = __ps2_command(ps2dev, param, command); + ps2_end_command(ps2dev); + + return rc; +} +EXPORT_SYMBOL(ps2_command); + +/** + * 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; + int retval; + + ps2_begin_command(ps2dev); + + retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11); + if (retval) + goto out; + + for (i = 6; i >= 0; i -= 2) { + u8 d = (command >> i) & 3; + retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES); + if (retval) + break; + } + +out: + dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval); + ps2_end_command(ps2dev); + return retval; +} +EXPORT_SYMBOL(ps2_sliced_command); + +/** + * 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, + 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); + ps2dev->serio = serio; + serio_set_drvdata(serio, ps2dev); +} +EXPORT_SYMBOL(ps2_init); + +/* + * 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; + + 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: + ps2dev->nak = 0; + break; + + case PS2_RET_NAK: + ps2dev->flags |= PS2_FLAG_NAK; + ps2dev->nak = PS2_RET_NAK; + break; + + case PS2_RET_ERR: + if (ps2dev->flags & PS2_FLAG_NAK) { + ps2dev->flags &= ~PS2_FLAG_NAK; + ps2dev->nak = PS2_RET_ERR; + break; + } + fallthrough; + + /* + * Workaround for mice which don't ACK the Get ID command. + * These are valid mouse IDs that we recognize. + */ + case 0x00: + case 0x03: + case 0x04: + if (ps2dev->flags & PS2_FLAG_WAITID) { + ps2dev->nak = 0; + break; + } + fallthrough; + default: + /* + * Do not signal errors if we get unexpected reply while + * waiting for an ACK to the initial (first) command byte: + * the device might not be quiesced yet and continue + * delivering data. For certain commands (such as set leds and + * set repeat rate) that can be used during normal device + * operation, we even pass this data byte to the normal receive + * handler. + * Note that we reset PS2_FLAG_WAITID flag, so the workaround + * for mice not acknowledging the Get ID command only triggers + * on the 1st byte; if device spews data we really want to see + * a real ACK from it. + */ + dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data); + if (ps2dev->flags & PS2_FLAG_PASS_NOACK) + ps2dev->receive_handler(ps2dev, data); + ps2dev->flags &= ~(PS2_FLAG_WAITID | PS2_FLAG_PASS_NOACK); + return; + } + + if (!ps2dev->nak) + ps2dev->flags &= ~PS2_FLAG_NAK; + + ps2dev->flags &= ~PS2_FLAG_ACK; + + if (!ps2dev->nak && data != PS2_RET_ACK) + ps2_handle_response(ps2dev, data); + else + wake_up(&ps2dev->wait); +} + +/* + * Clears state of PS/2 device after communication error by resetting majority + * of flags and waking up waiters, if any. + */ +static void ps2_cleanup(struct ps2dev *ps2dev) +{ + unsigned long old_flags = ps2dev->flags; + + /* reset all flags except last nak */ + ps2dev->flags &= PS2_FLAG_NAK; + + if (old_flags & PS2_FLAG_ACK) + ps2dev->nak = 1; + + 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_interrupt); + +MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>"); +MODULE_DESCRIPTION("PS/2 driver library"); +MODULE_LICENSE("GPL"); |