It is easier and faster to do transaction directly from interrupt context rather than waking control thread. Also, cleaner GPE storm avoidance is implemented. References: http://bugzilla.kernel.org/show_bug.cgi?id=9998 http://bugzilla.kernel.org/show_bug.cgi?id=10724 http://bugzilla.kernel.org/show_bug.cgi?id=10919 http://bugzilla.kernel.org/show_bug.cgi?id=11309 http://bugzilla.kernel.org/show_bug.cgi?id=11549 Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx> --- drivers/acpi/ec.c | 309 ++++++++++++++++++++++++++--------------------------- 1 files changed, 149 insertions(+), 160 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 13593f9..7f0d81c 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -1,7 +1,7 @@ /* - * ec.c - ACPI Embedded Controller Driver (v2.0) + * ec.c - ACPI Embedded Controller Driver (v2.1) * - * Copyright (C) 2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@xxxxxxxxx> + * Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@xxxxxxx> * Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@xxxxxxxxx> * Copyright (C) 2004 Luming Yu <luming.yu@xxxxxxxxx> * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@xxxxxxxxx> @@ -26,7 +26,7 @@ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ -/* Uncomment next line to get verbose print outs*/ +/* Uncomment next line to get verbose printout */ /* #define DEBUG */ #include <linux/kernel.h> @@ -38,6 +38,7 @@ #include <linux/seq_file.h> #include <linux/interrupt.h> #include <linux/list.h> +#include <linux/spinlock.h> #include <asm/io.h> #include <acpi/acpi_bus.h> #include <acpi/acpi_drivers.h> @@ -65,22 +66,21 @@ enum ec_command { ACPI_EC_COMMAND_QUERY = 0x84, }; -/* EC events */ -enum ec_event { - ACPI_EC_EVENT_OBF_1 = 1, /* Output buffer full */ - ACPI_EC_EVENT_IBF_0, /* Input buffer empty */ -}; - #define ACPI_EC_DELAY 500 /* Wait 500ms max. during EC ops */ #define ACPI_EC_UDELAY_GLK 1000 /* Wait 1ms max. to get global lock */ #define ACPI_EC_UDELAY 100 /* Wait 100us before polling EC again */ +#define ACPI_EC_STORM_THRESHOLD 20 /* number of false interrupts + per one transaction */ + enum { - EC_FLAGS_WAIT_GPE = 0, /* Don't check status until GPE arrives */ EC_FLAGS_QUERY_PENDING, /* Query is pending */ - EC_FLAGS_GPE_MODE, /* Expect GPE to be sent for status change */ + EC_FLAGS_GPE_MODE, /* Expect GPE to be sent + * for status change */ EC_FLAGS_NO_GPE, /* Don't use GPE mode */ - EC_FLAGS_RESCHEDULE_POLL /* Re-schedule poll */ + EC_FLAGS_GPE_STORM, /* GPE storm detected */ + EC_FLAGS_HANDLERS_INSTALLED /* Handlers for GPE and + * OpReg are installed */ }; /* If we find an EC via the ECDT, we need to keep a ptr to its context */ @@ -95,6 +95,14 @@ struct acpi_ec_query_handler { u8 query_bit; }; +struct transaction_data { + const u8 *wdata; + u8 *rdata; + unsigned short irq_count; + u8 wlen; + u8 rlen; +}; + static struct acpi_ec { acpi_handle handle; unsigned long gpe; @@ -105,9 +113,8 @@ static struct acpi_ec { struct mutex lock; wait_queue_head_t wait; struct list_head list; - struct delayed_work work; - atomic_t irq_count; - u8 handlers_installed; + struct transaction_data *t; + spinlock_t t_lock; } *boot_ec, *first_ec; /* @@ -150,7 +157,7 @@ static inline u8 acpi_ec_read_data(struct acpi_ec *ec) { u8 x = inb(ec->data_addr); pr_debug(PREFIX "---> data = 0x%2.2x\n", x); - return inb(ec->data_addr); + return x; } static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command) @@ -165,68 +172,79 @@ static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data) outb(data, ec->data_addr); } -static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event) +static int ec_transaction_done(struct acpi_ec *ec) { - if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags)) - return 0; - if (event == ACPI_EC_EVENT_OBF_1) { - if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF) - return 1; - } else if (event == ACPI_EC_EVENT_IBF_0) { - if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)) - return 1; - } - - return 0; + unsigned long flags; + int ret = 0; + spin_lock_irqsave(&ec->t_lock, flags); + if (!ec->t || (!ec->t->wlen && !ec->t->rlen)) + ret = 1; + spin_unlock_irqrestore(&ec->t_lock, flags); + return ret; } -static void ec_schedule_ec_poll(struct acpi_ec *ec) +static void gpe_transaction(struct acpi_ec *ec, u8 status) { - if (test_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags)) - schedule_delayed_work(&ec->work, - msecs_to_jiffies(ACPI_EC_DELAY)); + unsigned long flags; + spin_lock_irqsave(&ec->t_lock, flags); + if (!ec->t) + goto unlock; + if (ec->t->wlen > 0) { + if ((status & ACPI_EC_FLAG_IBF) == 0) { + acpi_ec_write_data(ec, *(ec->t->wdata++)); + --ec->t->wlen; + } else + /* false interrupt, state didn't change */ + ++ec->t->irq_count; + + } else if (ec->t->rlen > 0) { + if ((status & ACPI_EC_FLAG_OBF) == 1) { + *(ec->t->rdata++) = acpi_ec_read_data(ec); + --ec->t->rlen; + } else + /* false interrupt, state didn't change */ + ++ec->t->irq_count; + } +unlock: + spin_unlock_irqrestore(&ec->t_lock, flags); } -static void ec_switch_to_poll_mode(struct acpi_ec *ec) +static int acpi_ec_wait(struct acpi_ec *ec) { + if (wait_event_timeout(ec->wait, ec_transaction_done(ec), + msecs_to_jiffies(ACPI_EC_DELAY))) + return 0; + /* missing GPEs, switch back to poll mode */ + if (printk_ratelimit()) + pr_info(PREFIX "missing confirmations, " + "switch off interrupt mode.\n"); set_bit(EC_FLAGS_NO_GPE, &ec->flags); clear_bit(EC_FLAGS_GPE_MODE, &ec->flags); - acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); - set_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags); + return 1; } -static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll) +static void acpi_ec_gpe_query(void *ec_cxt); + +static int ec_check_sci(struct acpi_ec *ec, u8 state) { - atomic_set(&ec->irq_count, 0); - if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) && - likely(!force_poll)) { - if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event), - msecs_to_jiffies(ACPI_EC_DELAY))) - return 0; - clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags); - if (acpi_ec_check_status(ec, event)) { - /* missing GPEs, switch back to poll mode */ - if (printk_ratelimit()) - pr_info(PREFIX "missing confirmations, " - "switch off interrupt mode.\n"); - ec_switch_to_poll_mode(ec); - ec_schedule_ec_poll(ec); - return 0; - } - } else { - unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY); - clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags); - while (time_before(jiffies, delay)) { - if (acpi_ec_check_status(ec, event)) - return 0; - msleep(1); - } - if (acpi_ec_check_status(ec,event)) + if (state & ACPI_EC_FLAG_SCI) { + if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) + return acpi_os_execute(OSL_EC_BURST_HANDLER, + acpi_ec_gpe_query, ec); + } + return 0; +} + +static int ec_poll(struct acpi_ec *ec) +{ + unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY); + msleep(1); + while (time_before(jiffies, delay)) { + gpe_transaction(ec, acpi_ec_read_status(ec)); + msleep(1); + if (ec_transaction_done(ec)) return 0; } - pr_err(PREFIX "acpi_ec_wait timeout, status = 0x%2.2x, event = %s\n", - acpi_ec_read_status(ec), - (event == ACPI_EC_EVENT_OBF_1) ? "\"b0=1\"" : "\"b1=0\""); return -ETIME; } @@ -235,45 +253,51 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command, u8 * rdata, unsigned rdata_len, int force_poll) { - int result = 0; - set_bit(EC_FLAGS_WAIT_GPE, &ec->flags); + unsigned long tmp; + struct transaction_data t = {.wdata = wdata, .rdata = rdata, + .wlen = wdata_len, .rlen = rdata_len, + .irq_count = 0}; + int ret = 0; pr_debug(PREFIX "transaction start\n"); - acpi_ec_write_cmd(ec, command); - for (; wdata_len > 0; --wdata_len) { - result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll); - if (result) { - pr_err(PREFIX - "write_cmd timeout, command = %d\n", command); - goto end; - } - set_bit(EC_FLAGS_WAIT_GPE, &ec->flags); - acpi_ec_write_data(ec, *(wdata++)); + /* disable GPE during transaction if storm is detected */ + if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) { + clear_bit(EC_FLAGS_GPE_MODE, &ec->flags); + acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); } - - if (!rdata_len) { - result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll); - if (result) { - pr_err(PREFIX - "finish-write timeout, command = %d\n", command); - goto end; - } - } else if (command == ACPI_EC_COMMAND_QUERY) + /* start transaction */ + spin_lock_irqsave(&ec->t_lock, tmp); + /* following two actions should be kept atomic */ + ec->t = &t; + acpi_ec_write_cmd(ec, command); + if (command == ACPI_EC_COMMAND_QUERY) clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags); - - for (; rdata_len > 0; --rdata_len) { - result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll); - if (result) { - pr_err(PREFIX "read timeout, command = %d\n", command); - goto end; - } - /* Don't expect GPE after last read */ - if (rdata_len > 1) - set_bit(EC_FLAGS_WAIT_GPE, &ec->flags); - *(rdata++) = acpi_ec_read_data(ec); - } - end: + spin_unlock_irqrestore(&ec->t_lock, tmp); + /* if we selected poll mode or failed in GPE-mode do a poll loop */ + if (force_poll || + !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) || + acpi_ec_wait(ec)) + ret = ec_poll(ec); pr_debug(PREFIX "transaction end\n"); - return result; + spin_lock_irqsave(&ec->t_lock, tmp); + ec->t = NULL; + spin_unlock_irqrestore(&ec->t_lock, tmp); + if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) { + /* check if we received SCI during transaction */ + ec_check_sci(ec, acpi_ec_read_status(ec)); + /* it is safe to enable GPE outside of transaction */ + acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); + } else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) && + t.irq_count > ACPI_EC_STORM_THRESHOLD) { + pr_debug(PREFIX "GPE storm detected\n"); + set_bit(EC_FLAGS_GPE_STORM, &ec->flags); + } + return ret; +} + +static int ec_check_ibf0(struct acpi_ec *ec) +{ + u8 status = acpi_ec_read_status(ec); + return (status & ACPI_EC_FLAG_IBF) == 0; } static int acpi_ec_transaction(struct acpi_ec *ec, u8 command, @@ -283,40 +307,34 @@ static int acpi_ec_transaction(struct acpi_ec *ec, u8 command, { int status; u32 glk; - if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata)) return -EINVAL; - if (rdata) memset(rdata, 0, rdata_len); - mutex_lock(&ec->lock); if (ec->global_lock) { status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk); if (ACPI_FAILURE(status)) { - mutex_unlock(&ec->lock); - return -ENODEV; + status = -ENODEV; + goto unlock; } } - - status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0); - if (status) { + if (!wait_event_timeout(ec->wait, ec_check_ibf0(ec), + msecs_to_jiffies(ACPI_EC_DELAY))) { pr_err(PREFIX "input buffer is not empty, " "aborting transaction\n"); + status = -ETIME; goto end; } - status = acpi_ec_transaction_unlocked(ec, command, wdata, wdata_len, rdata, rdata_len, force_poll); - - end: - +end: if (ec->global_lock) acpi_release_global_lock(glk); +unlock: mutex_unlock(&ec->lock); - return status; } @@ -332,7 +350,9 @@ int acpi_ec_burst_enable(struct acpi_ec *ec) int acpi_ec_burst_disable(struct acpi_ec *ec) { - return acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE, NULL, 0, NULL, 0, 0); + return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ? + acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE, + NULL, 0, NULL, 0, 0) : 0; } static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data) @@ -513,46 +533,26 @@ static void acpi_ec_gpe_query(void *ec_cxt) static u32 acpi_ec_gpe_handler(void *data) { - acpi_status status = AE_OK; struct acpi_ec *ec = data; - u8 state = acpi_ec_read_status(ec); + u8 status; pr_debug(PREFIX "~~~> interrupt\n"); - atomic_inc(&ec->irq_count); - if (atomic_read(&ec->irq_count) > 5) { - pr_err(PREFIX "GPE storm detected, disabling EC GPE\n"); - ec_switch_to_poll_mode(ec); - goto end; - } - clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags); - if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) + status = acpi_ec_read_status(ec); + + gpe_transaction(ec, status); + if (ec_transaction_done(ec) && (status & ACPI_EC_FLAG_IBF) == 0) wake_up(&ec->wait); - if (state & ACPI_EC_FLAG_SCI) { - if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) - status = acpi_os_execute(OSL_EC_BURST_HANDLER, - acpi_ec_gpe_query, ec); - } else if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) && - !test_bit(EC_FLAGS_NO_GPE, &ec->flags) && - in_interrupt()) { + ec_check_sci(ec, status); + if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) && + !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) { /* this is non-query, must be confirmation */ if (printk_ratelimit()) pr_info(PREFIX "non-query interrupt received," " switching to interrupt mode\n"); set_bit(EC_FLAGS_GPE_MODE, &ec->flags); - clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags); } -end: - ec_schedule_ec_poll(ec); - return ACPI_SUCCESS(status) ? - ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED; -} - -static void do_ec_poll(struct work_struct *work) -{ - struct acpi_ec *ec = container_of(work, struct acpi_ec, work.work); - atomic_set(&ec->irq_count, 0); - (void)acpi_ec_gpe_handler(ec); + return ACPI_INTERRUPT_HANDLED; } /* -------------------------------------------------------------------------- @@ -696,8 +696,7 @@ static struct acpi_ec *make_acpi_ec(void) mutex_init(&ec->lock); init_waitqueue_head(&ec->wait); INIT_LIST_HEAD(&ec->list); - INIT_DELAYED_WORK_DEFERRABLE(&ec->work, do_ec_poll); - atomic_set(&ec->irq_count, 0); + spin_lock_init(&ec->t_lock); return ec; } @@ -736,22 +735,15 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval) return AE_CTRL_TERMINATE; } -static void ec_poll_stop(struct acpi_ec *ec) -{ - clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags); - cancel_delayed_work(&ec->work); -} - static void ec_remove_handlers(struct acpi_ec *ec) { - ec_poll_stop(ec); if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler))) pr_err(PREFIX "failed to remove space handler\n"); if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler))) pr_err(PREFIX "failed to remove gpe handler\n"); - ec->handlers_installed = 0; + clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags); } static int acpi_ec_add(struct acpi_device *device) @@ -846,17 +838,15 @@ ec_parse_io_ports(struct acpi_resource *resource, void *context) static int ec_install_handlers(struct acpi_ec *ec) { acpi_status status; - if (ec->handlers_installed) + if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags)) return 0; status = acpi_install_gpe_handler(NULL, ec->gpe, - ACPI_GPE_EDGE_TRIGGERED, - &acpi_ec_gpe_handler, ec); + ACPI_GPE_EDGE_TRIGGERED, + &acpi_ec_gpe_handler, ec); if (ACPI_FAILURE(status)) return -ENODEV; - acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME); acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); - status = acpi_install_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler, @@ -866,7 +856,7 @@ static int ec_install_handlers(struct acpi_ec *ec) return -ENODEV; } - ec->handlers_installed = 1; + set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags); return 0; } @@ -887,7 +877,6 @@ static int acpi_ec_start(struct acpi_device *device) /* EC is fully operational, allow queries */ clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags); - ec_schedule_ec_poll(ec); return ret; } @@ -906,7 +895,7 @@ static int acpi_ec_stop(struct acpi_device *device, int type) int __init acpi_boot_ec_enable(void) { - if (!boot_ec || boot_ec->handlers_installed) + if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags)) return 0; if (!ec_install_handlers(boot_ec)) { first_ec = boot_ec; -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
