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ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag
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 <lv.zheng@intel.com> Tested-by: Ortwin Glück <odi@odi.ch> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -80,7 +80,8 @@ enum {
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EC_FLAGS_GPE_STORM, /* GPE storm detected */
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EC_FLAGS_HANDLERS_INSTALLED, /* Handlers for GPE and
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* OpReg are installed */
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EC_FLAGS_BLOCKED, /* Transactions are blocked */
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EC_FLAGS_STARTED, /* Driver is started */
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EC_FLAGS_STOPPED, /* Driver is stopped */
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};
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#define ACPI_EC_COMMAND_POLL 0x01 /* Available for command byte */
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@ -134,6 +135,16 @@ static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
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static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
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static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
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/* --------------------------------------------------------------------------
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* Device Flags
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* -------------------------------------------------------------------------- */
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static bool acpi_ec_started(struct acpi_ec *ec)
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{
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return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
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!test_bit(EC_FLAGS_STOPPED, &ec->flags);
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}
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/* --------------------------------------------------------------------------
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* EC Registers
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* -------------------------------------------------------------------------- */
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@ -415,6 +426,10 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
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udelay(ACPI_EC_MSI_UDELAY);
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/* start transaction */
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spin_lock_irqsave(&ec->lock, tmp);
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if (!acpi_ec_started(ec)) {
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ret = -EINVAL;
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goto unlock;
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}
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/* following two actions should be kept atomic */
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ec->curr = t;
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pr_debug("***** Command(%s) started *****\n",
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@ -426,6 +441,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
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pr_debug("***** Command(%s) stopped *****\n",
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acpi_ec_cmd_string(t->command));
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ec->curr = NULL;
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unlock:
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spin_unlock_irqrestore(&ec->lock, tmp);
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return ret;
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}
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@ -440,10 +456,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
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if (t->rdata)
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memset(t->rdata, 0, t->rlen);
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mutex_lock(&ec->mutex);
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if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
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status = -EINVAL;
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goto unlock;
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}
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if (ec->global_lock) {
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status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
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if (ACPI_FAILURE(status)) {
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@ -595,6 +607,37 @@ static void acpi_ec_clear(struct acpi_ec *ec)
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pr_info("%d stale EC events cleared\n", i);
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}
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static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
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{
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unsigned long flags;
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spin_lock_irqsave(&ec->lock, flags);
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if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
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pr_debug("+++++ Starting EC +++++\n");
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if (!resuming)
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acpi_ec_enable_gpe(ec, true);
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pr_info("+++++ EC started +++++\n");
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}
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spin_unlock_irqrestore(&ec->lock, flags);
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}
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static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
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{
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unsigned long flags;
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spin_lock_irqsave(&ec->lock, flags);
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if (acpi_ec_started(ec)) {
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pr_debug("+++++ Stopping EC +++++\n");
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set_bit(EC_FLAGS_STOPPED, &ec->flags);
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if (!suspending)
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acpi_ec_disable_gpe(ec, true);
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clear_bit(EC_FLAGS_STARTED, &ec->flags);
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clear_bit(EC_FLAGS_STOPPED, &ec->flags);
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pr_info("+++++ EC stopped +++++\n");
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}
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spin_unlock_irqrestore(&ec->lock, flags);
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}
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void acpi_ec_block_transactions(void)
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{
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struct acpi_ec *ec = first_ec;
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@ -604,7 +647,7 @@ void acpi_ec_block_transactions(void)
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mutex_lock(&ec->mutex);
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/* Prevent transactions from being carried out */
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set_bit(EC_FLAGS_BLOCKED, &ec->flags);
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acpi_ec_stop(ec, true);
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mutex_unlock(&ec->mutex);
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}
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@ -616,7 +659,7 @@ void acpi_ec_unblock_transactions(void)
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return;
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/* Allow transactions to be carried out again */
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clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
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acpi_ec_start(ec, true);
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if (EC_FLAGS_CLEAR_ON_RESUME)
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acpi_ec_clear(ec);
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@ -629,7 +672,7 @@ void acpi_ec_unblock_transactions_early(void)
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* atomic context during wakeup, so we don't need to acquire the mutex).
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*/
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if (first_ec)
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clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
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acpi_ec_start(first_ec, true);
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}
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/* --------------------------------------------------------------------------
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@ -894,7 +937,7 @@ static int ec_install_handlers(struct acpi_ec *ec)
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if (ACPI_FAILURE(status))
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return -ENODEV;
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acpi_ec_enable_gpe(ec, true);
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acpi_ec_start(ec, false);
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status = acpi_install_address_space_handler(ec->handle,
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ACPI_ADR_SPACE_EC,
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&acpi_ec_space_handler,
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@ -909,7 +952,7 @@ static int ec_install_handlers(struct acpi_ec *ec)
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pr_err("Fail in evaluating the _REG object"
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" of EC device. Broken bios is suspected.\n");
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} else {
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acpi_ec_disable_gpe(ec, true);
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acpi_ec_stop(ec, false);
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acpi_remove_gpe_handler(NULL, ec->gpe,
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&acpi_ec_gpe_handler);
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return -ENODEV;
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@ -924,7 +967,7 @@ static void ec_remove_handlers(struct acpi_ec *ec)
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{
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if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
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return;
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acpi_ec_disable_gpe(ec, true);
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acpi_ec_stop(ec, false);
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if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
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ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
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pr_err("failed to remove space handler\n");
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