drivers/wifi: Remove unnecessary data structure copy

The current design has the emit_wifi_sar_acpi_structures() function
load and unload the SAR binary. Since DSM and Bluetooth SAR data
structures are used outside this function, they are being copied into
data structure located in the calling function stack. This overhead is
unnecessary as loading and unloading the SAR binary could be done by
the calling function.

In addition, we are about to add several Bluetooth related data
structures which, under the current design, would require to add even
more data structure copy operations.

BUG=b:346600091
TEST=Wifi/Bluetooth SAR ACPI tables are identical before and after
     this commit

Change-Id: Iebe95815c944d045f4cf686abcd1874a8a45e207
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84940
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>

1 files changed, 33 insertions, 41 deletions

diff --git a/src/drivers/wifi/generic/acpi.c b/src/drivers/wifi/generic/acpi.c
index 81620f7505..9ed17e0b5c 100644
--- a/src/drivers/wifi/generic/acpi.c
+++ b/src/drivers/wifi/generic/acpi.c
@@ -582,6 +582,9 @@ static void sar_emit_brds(const struct bsar_profile *bsar)
 	size_t package_size, table_size;
 	const uint8_t *set;
 
+	if (bsar == NULL)
+		return;
+
 	/*
 	 * Name ("BRDS", Package () {
 	 *   Revision,
@@ -663,11 +666,9 @@ static void sar_emit_wbem(const struct wbem_profile *wbem)
 	acpigen_write_package_end();
 }
 
-static void emit_sar_acpi_structures(const struct device *dev, struct dsm_profile *dsm,
-				     struct bsar_profile *bsar, bool *bsar_loaded)
+static void emit_wifi_sar_acpi_structures(const struct device *dev,
+					  union wifi_sar_limits *sar_limits)
 {
-	union wifi_sar_limits sar_limits = {0};
-
 	/*
 	 * If device type is PCI, ensure that the device has Intel vendor ID. CBFS SAR and SAR
 	 * ACPI tables are currently used only by Intel WiFi devices.
@@ -675,30 +676,12 @@ static void emit_sar_acpi_structures(const struct device *dev, struct dsm_profil
 	if (dev->path.type == DEVICE_PATH_PCI && dev->vendor != PCI_VID_INTEL)
 		return;
 
-	/* Retrieve the SAR limits data */
-	if (get_wifi_sar_limits(&sar_limits) < 0) {
-		printk(BIOS_ERR, "failed getting SAR limits!\n");
-		return;
-	}
-
-	sar_emit_wrds(sar_limits.sar);
-	sar_emit_ewrd(sar_limits.sar);
-	sar_emit_wgds(sar_limits.wgds);
-	sar_emit_ppag(sar_limits.ppag);
-	sar_emit_wtas(sar_limits.wtas);
-	sar_emit_wbem(sar_limits.wbem);
-
-	/* copy the dsm data to be later used for creating _DSM function */
-	if (sar_limits.dsm != NULL)
-		memcpy(dsm, sar_limits.dsm, sizeof(struct dsm_profile));
-
-	/* copy the bsar data to be later used for creating Bluetooth BRDS method */
-	if (sar_limits.bsar != NULL) {
-		memcpy(bsar, sar_limits.bsar, sizeof(struct bsar_profile));
-		*bsar_loaded = true;
-	}
-
-	free(sar_limits.sar);
+	sar_emit_wrds(sar_limits->sar);
+	sar_emit_ewrd(sar_limits->sar);
+	sar_emit_wgds(sar_limits->wgds);
+	sar_emit_ppag(sar_limits->ppag);
+	sar_emit_wtas(sar_limits->wtas);
+	sar_emit_wbem(sar_limits->wbem);
 }
 
 static void wifi_ssdt_write_device(const struct device *dev, const char *path)
@@ -756,26 +739,32 @@ static void wifi_ssdt_write_properties(const struct device *dev, const char *sco
 	}
 
 	struct dsm_uuid dsm_ids[MAX_DSM_FUNCS];
-	/* We will need a copy dsm data to be used later for creating _DSM function */
-	struct dsm_profile dsm = {0};
-	/* We will need a copy of bsar data to be used later for creating BRDS function */
-	struct bsar_profile bsar = {0};
-	bool bsar_loaded = false;
-	uint8_t dsm_count = 0;
 
-	/* Fill Wifi SAR related ACPI structures */
+	/* Retrieve the SAR limits data */
+	union wifi_sar_limits sar_limits = {0};
+	bool sar_loaded = false;
 	if (CONFIG(USE_SAR)) {
-		emit_sar_acpi_structures(dev, &dsm, &bsar, &bsar_loaded);
+		if (get_wifi_sar_limits(&sar_limits) < 0)
+			printk(BIOS_ERR, "failed getting SAR limits!\n");
+		else
+			sar_loaded = true;
+	}
 
-		if (dsm.supported_functions != 0) {
+	/* Fill Wifi SAR related ACPI structures */
+	uint8_t dsm_count = 0;
+	if (sar_loaded) {
+		emit_wifi_sar_acpi_structures(dev, &sar_limits);
+
+		struct dsm_profile *dsm = sar_limits.dsm;
+		if (dsm && dsm->supported_functions != 0) {
 			for (int i = 1; i < ARRAY_SIZE(wifi_dsm_callbacks); i++)
-				if (!(dsm.supported_functions & (1 << i)))
+				if (!(dsm->supported_functions & (1 << i)))
 					wifi_dsm_callbacks[i] = NULL;
 
 			dsm_ids[dsm_count].uuid = ACPI_DSM_OEM_WIFI_UUID;
 			dsm_ids[dsm_count].callbacks = &wifi_dsm_callbacks[0];
 			dsm_ids[dsm_count].count = ARRAY_SIZE(wifi_dsm_callbacks);
-			dsm_ids[dsm_count].arg = &dsm;
+			dsm_ids[dsm_count].arg = dsm;
 			dsm_count++;
 		}
 	}
@@ -804,11 +793,11 @@ static void wifi_ssdt_write_properties(const struct device *dev, const char *sco
 	acpigen_write_scope_end(); /* Scope */
 
 	/* Fill Bluetooth companion SAR related ACPI structures */
-	if (bsar_loaded && is_dev_enabled(config->bluetooth_companion)) {
+	if (sar_loaded && is_dev_enabled(config->bluetooth_companion)) {
 		const char *path = acpi_device_path(config->bluetooth_companion);
 		if (path) {	/* Bluetooth device under USB Hub scope or PCIe root port */
 			acpigen_write_scope(path);
-			sar_emit_brds(&bsar);
+			sar_emit_brds(sar_limits.bsar);
 			acpigen_write_scope_end();
 		} else {
 			printk(BIOS_ERR, "Failed to get %s Bluetooth companion ACPI path\n",
@@ -816,6 +805,9 @@ static void wifi_ssdt_write_properties(const struct device *dev, const char *sco
 		}
 	}
 
+	if (sar_loaded)
+		free(sar_limits.sar);
+
 	printk(BIOS_INFO, "%s: %s %s\n", scope, dev->chip_ops ? dev->chip_ops->name : "",
 	       dev_path(dev));
 }