From c374a0cdab372c350ce9e2f8cb438d6175bac9f2 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 4 Sep 2024 21:17:17 -0700 Subject: [PATCH] Input: i8042 - tease apart interrupt handler In preparation to using guard notation when acquiring mutexes and spinlocks factor out handling of active multiplexing mode from i8042_interrupt(). Link: https://lore.kernel.org/r/20240905041732.2034348-13-dmitry.torokhov@gmail.com Signed-off-by: Dmitry Torokhov --- drivers/input/serio/i8042.c | 151 +++++++++++++++++++++--------------- 1 file changed, 89 insertions(+), 62 deletions(-) diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c index 8ec4872b4471..674cd155ec8f 100644 --- a/drivers/input/serio/i8042.c +++ b/drivers/input/serio/i8042.c @@ -178,7 +178,7 @@ static unsigned char i8042_suppress_kbd_ack; static struct platform_device *i8042_platform_device; static struct notifier_block i8042_kbd_bind_notifier_block; -static irqreturn_t i8042_interrupt(int irq, void *dev_id); +static bool i8042_handle_data(int irq); static bool (*i8042_platform_filter)(unsigned char data, unsigned char str, struct serio *serio); @@ -434,7 +434,7 @@ static void i8042_port_close(struct serio *serio) * See if there is any data appeared while we were messing with * port state. */ - i8042_interrupt(0, NULL); + i8042_handle_data(0); } /* @@ -518,44 +518,10 @@ static bool i8042_filter(unsigned char data, unsigned char str, } /* - * i8042_interrupt() is the most important function in this driver - - * it handles the interrupts from the i8042, and sends incoming bytes - * to the upper layers. - */ - -static irqreturn_t i8042_interrupt(int irq, void *dev_id) -{ - struct i8042_port *port; - struct serio *serio; - unsigned long flags; - unsigned char str, data; - unsigned int dfl; - unsigned int port_no; - bool filtered; - int ret = 1; - - spin_lock_irqsave(&i8042_lock, flags); - - str = i8042_read_status(); - if (unlikely(~str & I8042_STR_OBF)) { - spin_unlock_irqrestore(&i8042_lock, flags); - if (irq) - dbg("Interrupt %d, without any data\n", irq); - ret = 0; - goto out; - } - - data = i8042_read_data(); - - if (i8042_mux_present && (str & I8042_STR_AUXDATA)) { - static unsigned long last_transmit; - static unsigned char last_str; - - dfl = 0; - if (str & I8042_STR_MUXERR) { - dbg("MUX error, status is %02x, data is %02x\n", - str, data); -/* + * i8042_handle_mux() handles case when data is coming from one of + * the multiplexed ports. It would be simple if not for quirks with + * handling errors: + * * When MUXERR condition is signalled the data register can only contain * 0xfd, 0xfe or 0xff if implementation follows the spec. Unfortunately * it is not always the case. Some KBCs also report 0xfc when there is @@ -567,28 +533,79 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id) * rest assume that the data came from the same serio last byte * was transmitted (if transmission happened not too long ago). */ +static int i8042_handle_mux(u8 str, u8 *data, unsigned int *dfl) +{ + static unsigned long last_transmit; + static unsigned long last_port; + unsigned int mux_port; - switch (data) { - default: - if (time_before(jiffies, last_transmit + HZ/10)) { - str = last_str; - break; - } - fallthrough; /* report timeout */ - case 0xfc: - case 0xfd: - case 0xfe: dfl = SERIO_TIMEOUT; data = 0xfe; break; - case 0xff: dfl = SERIO_PARITY; data = 0xfe; break; + mux_port = (str >> 6) & 3; + *dfl = 0; + + if (str & I8042_STR_MUXERR) { + dbg("MUX error, status is %02x, data is %02x\n", + str, *data); + + switch (*data) { + default: + if (time_before(jiffies, last_transmit + HZ/10)) { + mux_port = last_port; + break; } + fallthrough; /* report timeout */ + case 0xfc: + case 0xfd: + case 0xfe: + *dfl = SERIO_TIMEOUT; + *data = 0xfe; + break; + case 0xff: + *dfl = SERIO_PARITY; + *data = 0xfe; + break; } + } - port_no = I8042_MUX_PORT_NO + ((str >> 6) & 3); - last_str = str; - last_transmit = jiffies; + last_port = mux_port; + last_transmit = jiffies; + + return I8042_MUX_PORT_NO + mux_port; +} + +/* + * i8042_handle_data() is the most important function in this driver - + * it reads the data from the i8042, determines its destination serio + * port, and sends received byte to the upper layers. + * + * Returns true if there was data waiting, false otherwise. + */ +static bool i8042_handle_data(int irq) +{ + struct i8042_port *port; + struct serio *serio; + unsigned long flags; + unsigned char str, data; + unsigned int dfl; + unsigned int port_no; + bool filtered; + + spin_lock_irqsave(&i8042_lock, flags); + + str = i8042_read_status(); + if (unlikely(~str & I8042_STR_OBF)) { + spin_unlock_irqrestore(&i8042_lock, flags); + return false; + } + + data = i8042_read_data(); + + if (i8042_mux_present && (str & I8042_STR_AUXDATA)) { + port_no = i8042_handle_mux(str, &data, &dfl); } else { - dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) | - ((str & I8042_STR_TIMEOUT && !i8042_notimeout) ? SERIO_TIMEOUT : 0); + dfl = (str & I8042_STR_PARITY) ? SERIO_PARITY : 0; + if ((str & I8042_STR_TIMEOUT) && !i8042_notimeout) + dfl |= SERIO_TIMEOUT; port_no = (str & I8042_STR_AUXDATA) ? I8042_AUX_PORT_NO : I8042_KBD_PORT_NO; @@ -609,8 +626,17 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id) if (likely(serio && !filtered)) serio_interrupt(serio, data, dfl); - out: - return IRQ_RETVAL(ret); + return true; +} + +static irqreturn_t i8042_interrupt(int irq, void *dev_id) +{ + if (unlikely(!i8042_handle_data(irq))) { + dbg("Interrupt %d, without any data\n", irq); + return IRQ_NONE; + } + + return IRQ_HANDLED; } /* @@ -1216,13 +1242,14 @@ static int i8042_controller_resume(bool s2r_wants_reset) if (i8042_mux_present) { if (i8042_set_mux_mode(true, NULL) || i8042_enable_mux_ports()) pr_warn("failed to resume active multiplexor, mouse won't work\n"); - } else if (i8042_ports[I8042_AUX_PORT_NO].serio) + } else if (i8042_ports[I8042_AUX_PORT_NO].serio) { i8042_enable_aux_port(); + } if (i8042_ports[I8042_KBD_PORT_NO].serio) i8042_enable_kbd_port(); - i8042_interrupt(0, NULL); + i8042_handle_data(0); return 0; } @@ -1253,7 +1280,7 @@ static int i8042_pm_suspend(struct device *dev) static int i8042_pm_resume_noirq(struct device *dev) { if (i8042_forcenorestore || !pm_resume_via_firmware()) - i8042_interrupt(0, NULL); + i8042_handle_data(0); return 0; } @@ -1290,7 +1317,7 @@ static int i8042_pm_resume(struct device *dev) static int i8042_pm_thaw(struct device *dev) { - i8042_interrupt(0, NULL); + i8042_handle_data(0); return 0; }