iwlwifi: rely on API version read from firmware

This adds the infrastructure to support older firmware APIs.
The API version number is stored as part of the filename, we first try to
load the most recent firmware and progressively try lower versions.
The API version is also read from the firmware self and stored as part
of the iwl_priv structure. Only firmware that is supported by driver will
be loaded. The version number read from firmware is compared
to supported versions in the driver not the API version used as part of
filename.

An example using this new infrastrucure:
   if (IWL_UCODE_API(priv->ucode_ver) >= 2) {
        Driver interacts with Firmware API version >= 2.
   } else {
        Driver interacts with Firmware API version 1.
   }

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 49 insertions, 13 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 5912cdec33a7..b3c263d2724f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -1570,24 +1570,40 @@ static void iwl_nic_start(struct iwl_priv *priv)
 static int iwl_read_ucode(struct iwl_priv *priv)
 {
 	struct iwl_ucode *ucode;
-	int ret;
+	int ret = -EINVAL, index;
 	const struct firmware *ucode_raw;
-	const char *name = priv->cfg->fw_name;
+	const char *name_pre = priv->cfg->fw_name_pre;
+	const unsigned int api_max = priv->cfg->ucode_api_max;
+	const unsigned int api_min = priv->cfg->ucode_api_min;
+	char buf[25];
 	u8 *src;
 	size_t len;
-	u32 inst_size, data_size, init_size, init_data_size, boot_size;
+	u32 api_ver, inst_size, data_size, init_size, init_data_size, boot_size;
 
 	/* Ask kernel firmware_class module to get the boot firmware off disk.
 	 * request_firmware() is synchronous, file is in memory on return. */
-	ret = request_firmware(&ucode_raw, name, &priv->pci_dev->dev);
-	if (ret < 0) {
-		IWL_ERROR("%s firmware file req failed: Reason %d\n",
-					name, ret);
-		goto error;
+	for (index = api_max; index >= api_min; index--) {
+		sprintf(buf, "%s%d%s", name_pre, index, ".ucode");
+		ret = request_firmware(&ucode_raw, buf, &priv->pci_dev->dev);
+		if (ret < 0) {
+			IWL_ERROR("%s firmware file req failed: Reason %d\n",
+				  buf, ret);
+			if (ret == -ENOENT)
+				continue;
+			else
+				goto error;
+		} else {
+			if (index < api_max)
+				IWL_ERROR("Loaded firmware %s, which is deprecated. Please use API v%u instead.\n",
+					  buf, api_max);
+			IWL_DEBUG_INFO("Got firmware '%s' file (%zd bytes) from disk\n",
+				       buf, ucode_raw->size);
+			break;
+		}
 	}
 
-	IWL_DEBUG_INFO("Got firmware '%s' file (%zd bytes) from disk\n",
-		       name, ucode_raw->size);
+	if (ret < 0)
+		goto error;
 
 	/* Make sure that we got at least our header! */
 	if (ucode_raw->size < sizeof(*ucode)) {
@@ -1600,19 +1616,39 @@ static int iwl_read_ucode(struct iwl_priv *priv)
 	ucode = (void *)ucode_raw->data;
 
 	priv->ucode_ver = le32_to_cpu(ucode->ver);
+	api_ver = IWL_UCODE_API(priv->ucode_ver);
 	inst_size = le32_to_cpu(ucode->inst_size);
 	data_size = le32_to_cpu(ucode->data_size);
 	init_size = le32_to_cpu(ucode->init_size);
 	init_data_size = le32_to_cpu(ucode->init_data_size);
 	boot_size = le32_to_cpu(ucode->boot_size);
 
-	IWL_DEBUG_INFO("f/w package hdr ucode version raw = 0x%x\n",
-		       priv->ucode_ver);
-	IWL_DEBUG_INFO("f/w package hdr ucode version = %u.%u.%u.%u\n",
+	/* api_ver should match the api version forming part of the
+	 * firmware filename ... but we don't check for that and only rely
+	 * on the API version read from firware header from here on forward */
+
+	if (api_ver < api_min || api_ver > api_max) {
+		IWL_ERROR("Driver unable to support your firmware API. "
+			  "Driver supports v%u, firmware is v%u.\n",
+			  api_max, api_ver);
+		priv->ucode_ver = 0;
+		ret = -EINVAL;
+		goto err_release;
+	}
+	if (api_ver != api_max)
+		IWL_ERROR("Firmware has old API version. Expected v%u, "
+			  "got v%u. New firmware can be obtained "
+			  "from http://www.intellinuxwireless.org.\n",
+			  api_max, api_ver);
+
+	printk(KERN_INFO DRV_NAME " loaded firmware version %u.%u.%u.%u\n",
 		       IWL_UCODE_MAJOR(priv->ucode_ver),
 		       IWL_UCODE_MINOR(priv->ucode_ver),
 		       IWL_UCODE_API(priv->ucode_ver),
 		       IWL_UCODE_SERIAL(priv->ucode_ver));
+
+	IWL_DEBUG_INFO("f/w package hdr ucode version raw = 0x%x\n",
+		       priv->ucode_ver);
 	IWL_DEBUG_INFO("f/w package hdr runtime inst size = %u\n",
 		       inst_size);
 	IWL_DEBUG_INFO("f/w package hdr runtime data size = %u\n",