iwlwifi: mvm: send udev event upon firmware error to dump logs

When the firmware asserts, the driver will dump the firmware
state to an internal buffer. This buffer is kept aside until
it is dumped through debugfs. Once an external application
fetched the data, the buffer is freed and a new buffer can
be allocated in case another assert occurs.

A udev event is sent to trigger an external application.

A simple rule like:
DRIVER=="iwlwifi", ACTION=="change", RUN+="/sbin/dump_sram.sh"

can fetch the data from debugfs.

Here is my dump_sram.sh:

phyname=$(basename ${DEVPATH})
date=$(date +%F_%H_%M)
filename=/var/log/iwl-sram-${phyname}-${date}.bin
cat /sys/kernel/debug/ieee80211/${phyname}/iwlwifi/iwlmvm/fw_error_dump > ${filename}

The current SRAM size is 80KB so, currently:
$ ls -lh iwl-sram-phy0-2014-03-16_13_14.bin
-rw-r--r-- 1 emmanuel emmanuel 81K Mar 16 13:15 iwl-sram-phy0-2014-03-16_13_14.bin

and after compression:
$ ls -lh iwl-sram-phy0-2014-03-16_13_14.bin.xz
-rw-r--r-- 1 emmanuel emmanuel 13K Mar 16 13:15 iwl-sram-phy0-2014-03-16_13_14.bin.xz

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

1 files changed, 10 insertions, 17 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/utils.c b/drivers/net/wireless/iwlwifi/mvm/utils.c
index bbfe529d7b64..e9de033d6b9e 100644
--- a/drivers/net/wireless/iwlwifi/mvm/utils.c
+++ b/drivers/net/wireless/iwlwifi/mvm/utils.c
@@ -516,33 +516,26 @@ void iwl_mvm_dump_nic_error_log(struct iwl_mvm *mvm)
                 iwl_mvm_dump_umac_error_log(mvm);
 }
 
-void iwl_mvm_dump_sram(struct iwl_mvm *mvm)
+void iwl_mvm_fw_error_sram_dump(struct iwl_mvm *mvm)
 {
         const struct fw_img *img;
-        int ofs, len = 0;
-        int i;
-        __le32 *buf;
+        u32 ofs, sram_len;
+        void *sram;
 
-        if (!mvm->ucode_loaded)
+        if (!mvm->ucode_loaded || mvm->fw_error_sram)
                 return;
 
         img = &mvm->fw->img[mvm->cur_ucode];
         ofs = img->sec[IWL_UCODE_SECTION_DATA].offset;
-        len = img->sec[IWL_UCODE_SECTION_DATA].len;
+        sram_len = img->sec[IWL_UCODE_SECTION_DATA].len;
 
-        buf = kzalloc(len, GFP_ATOMIC);
-        if (!buf)
+        sram = kzalloc(sram_len, GFP_ATOMIC);
+        if (!sram)
                 return;
 
-        iwl_trans_read_mem_bytes(mvm->trans, ofs, buf, len);
-        len = len >> 2;
-        for (i = 0; i < len; i++) {
-                IWL_ERR(mvm, "0x%08X\n", le32_to_cpu(buf[i]));
-                /* Add a small delay to let syslog catch up */
-                udelay(10);
-        }
-
-        kfree(buf);
+        iwl_trans_read_mem_bytes(mvm->trans, ofs, sram, sram_len);
+        mvm->fw_error_sram = sram;
+        mvm->fw_error_sram_len = sram_len;
 }
 
 /**