[ACPI] Notify SMM of cpufreq

http://marc.theaimsgroup.com/?l=acpi4linux&m=109428989121089&w=2

Signed-off-by: Dominik Brodowski <linux@brodo.de>

1 files changed, 79 insertions, 8 deletions

diff --git a/drivers/acpi/processor.c b/drivers/acpi/processor.c
index 83fb743aa3e7..f55b23e0ecfa 100644
--- a/drivers/acpi/processor.c
+++ b/drivers/acpi/processor.c
@@ -762,7 +762,10 @@ static DECLARE_MUTEX(performance_sem);
  * policy is adjusted accordingly.
  */
 
-static int acpi_processor_ppc_is_init = 0;
+#define PPC_REGISTERED   1
+#define PPC_IN_USE       2
+
+static int acpi_processor_ppc_status = 0;
 
 static int acpi_processor_ppc_notifier(struct notifier_block *nb, 
 	unsigned long event,
@@ -820,6 +823,10 @@ acpi_processor_get_platform_limit (
 	 * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
 	 */
 	status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
+
+	if (status != AE_NOT_FOUND)
+		acpi_processor_ppc_status |= PPC_IN_USE;
+
 	if(ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PPC\n"));
 		return_VALUE(-ENODEV);
@@ -844,17 +851,17 @@ static int acpi_processor_ppc_has_changed(
 
 static void acpi_processor_ppc_init(void) {
 	if (!cpufreq_register_notifier(&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
-		acpi_processor_ppc_is_init = 1;
+		acpi_processor_ppc_status |= PPC_REGISTERED;
 	else
 		printk(KERN_DEBUG "Warning: Processor Platform Limit not supported.\n");
 }
 
 
 static void acpi_processor_ppc_exit(void) {
-	if (acpi_processor_ppc_is_init)
+	if (acpi_processor_ppc_status & PPC_REGISTERED)
 		cpufreq_unregister_notifier(&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 
-	acpi_processor_ppc_is_init = 0;
+	acpi_processor_ppc_status &= ~PPC_REGISTERED;
 }
 
 /*
@@ -1074,6 +1081,73 @@ acpi_processor_get_performance_info (
 }
 
 
+int acpi_processor_notify_smm(struct module *calling_module) {
+	acpi_status		status;
+	static int		is_done = 0;
+
+	ACPI_FUNCTION_TRACE("acpi_processor_notify_smm");
+
+	if (!(acpi_processor_ppc_status & PPC_REGISTERED))
+		return_VALUE(-EBUSY);
+
+	if (!try_module_get(calling_module))
+		return_VALUE(-EINVAL);
+
+	/* is_done is set to negative if an error occured,
+	 * and to postitive if _no_ error occured, but SMM
+	 * was already notified. This avoids double notification
+	 * which might lead to unexpected results...
+	 */
+	if (is_done > 0) {
+		module_put(calling_module);
+		return_VALUE(0);
+	}
+	else if (is_done < 0) {
+		module_put(calling_module);
+		return_VALUE(is_done);
+	}
+
+	is_done = -EIO;
+
+	/* Can't write pstate_cnt to smi_cmd if either value is zero */
+	if ((!acpi_fadt.smi_cmd) ||
+	    (!acpi_fadt.pstate_cnt)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			"No SMI port or pstate_cnt\n"));
+		module_put(calling_module);
+		return_VALUE(0);
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Writing pstate_cnt [0x%x] to smi_cmd [0x%x]\n", acpi_fadt.pstate_cnt, acpi_fadt.smi_cmd));
+
+	/* FADT v1 doesn't support pstate_cnt, many BIOS vendors use
+	 * it anyway, so we need to support it... */
+	if (acpi_fadt_is_v1) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Using v1.0 FADT reserved value for pstate_cnt\n"));
+	}
+
+	status = acpi_os_write_port (acpi_fadt.smi_cmd,
+				     (u32) acpi_fadt.pstate_cnt, 8);
+	if (ACPI_FAILURE (status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
+				  "Failed to write pstate_cnt [0x%x] to "
+				  "smi_cmd [0x%x]\n", acpi_fadt.pstate_cnt, acpi_fadt.smi_cmd));
+		module_put(calling_module);
+		return_VALUE(status);
+	}
+
+	/* Success. If there's no _PPC, we need to fear nothing, so
+	 * we can allow the cpufreq driver to be rmmod'ed. */
+	is_done = 1;
+
+	if (!(acpi_processor_ppc_status & PPC_IN_USE))
+		module_put(calling_module);
+
+	return_VALUE(0);
+}
+EXPORT_SYMBOL(acpi_processor_notify_smm);
+
+
 #ifdef CONFIG_X86_ACPI_CPUFREQ_PROC_INTF
 /* /proc/acpi/processor/../performance interface (DEPRECATED) */
 
@@ -1230,7 +1304,7 @@ acpi_processor_register_performance (
 
 	ACPI_FUNCTION_TRACE("acpi_processor_register_performance");
 
-	if (!acpi_processor_ppc_is_init)
+	if (!(acpi_processor_ppc_status & PPC_REGISTERED))
 		return_VALUE(-EINVAL);
 
 	down(&performance_sem);
@@ -1271,9 +1345,6 @@ acpi_processor_unregister_performance (
 
 	ACPI_FUNCTION_TRACE("acpi_processor_unregister_performance");
 
-	if (!acpi_processor_ppc_is_init)
-		return_VOID;
-
 	down(&performance_sem);
 
 	pr = processors[cpu];