From ad479e7f47ca09c3f3190603ead4d01cf8fe6fa8 Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Fri, 6 Feb 2015 08:57:52 +0800 Subject: [PATCH] ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit By using the 2 flags, we can indicate an inter-mediate state where the current transactions should be completed while the new transactions should be dropped. The comparison of the old flag and the new flags: Old New about to set BLOCKED STOPPED set / STARTED set BLOCKED set STOPPED clear / STARTED clear BLOCKED clear STOPPED clear / STARTED set A new period can be indicated by the 2 flags. The new period is between the point where we are about to set BLOCKED and the point when the BLOCKED is set. The new flags facilitate us with acpi_ec_started() check to allow the EC transaction to be submitted during the new period. This period thus can be used as a grace period for the EC transaction flushing. The only functional change after applying this patch is: 1. The GPE enabling/disabling is protected by the EC specific lock. We can do this because of recent ACPICA GPE API enhancement. This is reasonable as the GPE disabling/enabling state should only be determined by the EC driver's state machine which is protected by the EC spinlock. Signed-off-by: Lv Zheng Tested-by: Ortwin Glück Signed-off-by: Rafael J. Wysocki --- drivers/acpi/ec.c | 65 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 54 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 55632539392d..a6179b71c573 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -80,7 +80,8 @@ enum { EC_FLAGS_GPE_STORM, /* GPE storm detected */ EC_FLAGS_HANDLERS_INSTALLED, /* Handlers for GPE and * OpReg are installed */ - EC_FLAGS_BLOCKED, /* Transactions are blocked */ + EC_FLAGS_STARTED, /* Driver is started */ + EC_FLAGS_STOPPED, /* Driver is stopped */ }; #define ACPI_EC_COMMAND_POLL 0x01 /* Available for command byte */ @@ -134,6 +135,16 @@ static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */ static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */ static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */ +/* -------------------------------------------------------------------------- + * Device Flags + * -------------------------------------------------------------------------- */ + +static bool acpi_ec_started(struct acpi_ec *ec) +{ + return test_bit(EC_FLAGS_STARTED, &ec->flags) && + !test_bit(EC_FLAGS_STOPPED, &ec->flags); +} + /* -------------------------------------------------------------------------- * EC Registers * -------------------------------------------------------------------------- */ @@ -415,6 +426,10 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, udelay(ACPI_EC_MSI_UDELAY); /* start transaction */ spin_lock_irqsave(&ec->lock, tmp); + if (!acpi_ec_started(ec)) { + ret = -EINVAL; + goto unlock; + } /* following two actions should be kept atomic */ ec->curr = t; pr_debug("***** Command(%s) started *****\n", @@ -426,6 +441,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, pr_debug("***** Command(%s) stopped *****\n", acpi_ec_cmd_string(t->command)); ec->curr = NULL; +unlock: spin_unlock_irqrestore(&ec->lock, tmp); return ret; } @@ -440,10 +456,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t) if (t->rdata) memset(t->rdata, 0, t->rlen); mutex_lock(&ec->mutex); - if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) { - status = -EINVAL; - goto unlock; - } if (ec->global_lock) { status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk); if (ACPI_FAILURE(status)) { @@ -595,6 +607,37 @@ static void acpi_ec_clear(struct acpi_ec *ec) pr_info("%d stale EC events cleared\n", i); } +static void acpi_ec_start(struct acpi_ec *ec, bool resuming) +{ + unsigned long flags; + + spin_lock_irqsave(&ec->lock, flags); + if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) { + pr_debug("+++++ Starting EC +++++\n"); + if (!resuming) + acpi_ec_enable_gpe(ec, true); + pr_info("+++++ EC started +++++\n"); + } + spin_unlock_irqrestore(&ec->lock, flags); +} + +static void acpi_ec_stop(struct acpi_ec *ec, bool suspending) +{ + unsigned long flags; + + spin_lock_irqsave(&ec->lock, flags); + if (acpi_ec_started(ec)) { + pr_debug("+++++ Stopping EC +++++\n"); + set_bit(EC_FLAGS_STOPPED, &ec->flags); + if (!suspending) + acpi_ec_disable_gpe(ec, true); + clear_bit(EC_FLAGS_STARTED, &ec->flags); + clear_bit(EC_FLAGS_STOPPED, &ec->flags); + pr_info("+++++ EC stopped +++++\n"); + } + spin_unlock_irqrestore(&ec->lock, flags); +} + void acpi_ec_block_transactions(void) { struct acpi_ec *ec = first_ec; @@ -604,7 +647,7 @@ void acpi_ec_block_transactions(void) mutex_lock(&ec->mutex); /* Prevent transactions from being carried out */ - set_bit(EC_FLAGS_BLOCKED, &ec->flags); + acpi_ec_stop(ec, true); mutex_unlock(&ec->mutex); } @@ -616,7 +659,7 @@ void acpi_ec_unblock_transactions(void) return; /* Allow transactions to be carried out again */ - clear_bit(EC_FLAGS_BLOCKED, &ec->flags); + acpi_ec_start(ec, true); if (EC_FLAGS_CLEAR_ON_RESUME) acpi_ec_clear(ec); @@ -629,7 +672,7 @@ void acpi_ec_unblock_transactions_early(void) * atomic context during wakeup, so we don't need to acquire the mutex). */ if (first_ec) - clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags); + acpi_ec_start(first_ec, true); } /* -------------------------------------------------------------------------- @@ -894,7 +937,7 @@ static int ec_install_handlers(struct acpi_ec *ec) if (ACPI_FAILURE(status)) return -ENODEV; - acpi_ec_enable_gpe(ec, true); + acpi_ec_start(ec, false); status = acpi_install_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler, @@ -909,7 +952,7 @@ static int ec_install_handlers(struct acpi_ec *ec) pr_err("Fail in evaluating the _REG object" " of EC device. Broken bios is suspected.\n"); } else { - acpi_ec_disable_gpe(ec, true); + acpi_ec_stop(ec, false); acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler); return -ENODEV; @@ -924,7 +967,7 @@ static void ec_remove_handlers(struct acpi_ec *ec) { if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags)) return; - acpi_ec_disable_gpe(ec, true); + acpi_ec_stop(ec, false); if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler))) pr_err("failed to remove space handler\n"); -- 2.34.1