mac80211: ath10k: search all IEs for variant before falling back

This patch adds the patch that was posted to ath10k-devel ML:
<https://patchwork.kernel.org/patch/10233491/>
|From: Thomas Hebb <tommyhebb@gmail.com>
|Subject: [PATCH] ath10k: search all IEs for variant before falling back
|Date: Wed, 21 Feb 2018 11:43:39 -0500
|[...]
|This patch fixes the issue by first searching the entire file for the ID
|with variant, and searching for the fallback ID only if that search
|fails. It also includes some code cleanup in the area, as
|ath10k_core_fetch_board_data_api_n() no longer does its own string
|mangling to remove the variant from an ID, instead leaving that job to a
|new flag passed to ath10k_core_create_board_name().
|
|I've tested this patch on a QCA4019 and verified that the driver behaves
|correctly for 1) both fallback and variant BDFs present, 2) only fallback
|BDF present, and 3) no matching BDFs present.
|
|Fixes: 1657b8f84ed9 ("ath10k: search SMBIOS for OEM board file extension")
|Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>

Note: 937-ath10k-calibration-variant.patch has been reassigned a new 081
number, as it now ships with upstream.... But also because this patch
requires the change in ath10k_core_create_board_name().

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

2 files changed, 237 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/937-ath10k-calibration-variant.patch b/package/kernel/mac80211/patches/081-ath10k-calibration-variant.patch
index f9a830c7a6..f9a830c7a6 100644
--- a/package/kernel/mac80211/patches/937-ath10k-calibration-variant.patch
+++ b/package/kernel/mac80211/patches/081-ath10k-calibration-variant.patch
diff --git a/package/kernel/mac80211/patches/160-ath10k-search-all-IEs-for-variant-before-falling-back.patch b/package/kernel/mac80211/patches/160-ath10k-search-all-IEs-for-variant-before-falling-back.patch
new file mode 100644
index 0000000000..cac396aeca
--- /dev/null
+++ b/package/kernel/mac80211/patches/160-ath10k-search-all-IEs-for-variant-before-falling-back.patch
@@ -0,0 +1,237 @@
+From: Thomas Hebb <tommyhebb@gmail.com>
+Subject: [PATCH] ath10k: search all IEs for variant before falling back
+Date: Wed, 21 Feb 2018 11:43:39 -0500
+
+commit f2593cb1b291 ("ath10k: Search SMBIOS for OEM board file
+extension") added a feature to ath10k that allows Board Data File
+(BDF) conflicts between multiple devices that use the same device IDs
+but have different calibration requirements to be resolved by allowing
+a "variant" string to be stored in SMBIOS [and later device tree, added
+by commit d06f26c5c8a4 ("ath10k: search DT for qcom,ath10k-calibration-
+variant")] that gets appended to the ID stored in board-2.bin.
+
+This original patch had a regression, however. Namely that devices with
+a variant present in SMBIOS that didn't need custom BDFs could no longer
+find the default BDF, which has no variant appended. The patch was
+reverted and re-applied with a fix for this issue in commit 1657b8f84ed9
+("search SMBIOS for OEM board file extension").
+
+But the fix to fall back to a default BDF introduced another issue: the
+driver currently parses IEs in board-2.bin one by one, and for each one
+it first checks to see if it matches the ID with the variant appended.
+If it doesn't, it checks to see if it matches the "fallback" ID with no
+variant. If a matching BDF is found at any point during this search, the
+search is terminated and that BDF is used. The issue is that it's very
+possible (and is currently the case for board-2.bin files present in the
+ath10k-firmware repository) for the default BDF to occur in an earlier
+IE than the variant-specific BDF. In this case, the current code will
+happily choose the default BDF even though a better-matching BDF is
+present later in the file.
+
+This patch fixes the issue by first searching the entire file for the ID
+with variant, and searching for the fallback ID only if that search
+fails. It also includes some code cleanup in the area, as
+ath10k_core_fetch_board_data_api_n() no longer does its own string
+mangling to remove the variant from an ID, instead leaving that job to a
+new flag passed to ath10k_core_create_board_name().
+
+I've tested this patch on a QCA4019 and verified that the driver behaves
+correctly for 1) both fallback and variant BDFs present, 2) only fallback
+BDF present, and 3) no matching BDFs present.
+
+Fixes: 1657b8f84ed9 ("ath10k: search SMBIOS for OEM board file extension")
+Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
+---
+ drivers/net/wireless/ath/ath10k/core.c | 134 ++++++++++++++++++---------------
+ 1 file changed, 72 insertions(+), 62 deletions(-)
+
+--- a/drivers/net/wireless/ath/ath10k/core.c
++++ b/drivers/net/wireless/ath/ath10k/core.c
+@@ -1129,14 +1129,61 @@ out:
+ 	return ret;
+ }
+ 
++static int ath10k_core_search_bd(struct ath10k *ar,
++				 const char *boardname,
++				 const u8 *data,
++				 size_t len)
++{
++	size_t ie_len;
++	struct ath10k_fw_ie *hdr;
++	int ret = -ENOENT, ie_id;
++
++	while (len > sizeof(struct ath10k_fw_ie)) {
++		hdr = (struct ath10k_fw_ie *)data;
++		ie_id = le32_to_cpu(hdr->id);
++		ie_len = le32_to_cpu(hdr->len);
++
++		len -= sizeof(*hdr);
++		data = hdr->data;
++
++		if (len < ALIGN(ie_len, 4)) {
++			ath10k_err(ar, "invalid length for board ie_id %d ie_len %zu len %zu\n",
++				   ie_id, ie_len, len);
++			return -EINVAL;
++		}
++
++		switch (ie_id) {
++		case ATH10K_BD_IE_BOARD:
++			ret = ath10k_core_parse_bd_ie_board(ar, data, ie_len,
++							    boardname);
++			if (ret == -ENOENT)
++				/* no match found, continue */
++				break;
++
++			/* either found or error, so stop searching */
++			goto out;
++		}
++
++		/* jump over the padding */
++		ie_len = ALIGN(ie_len, 4);
++
++		len -= ie_len;
++		data += ie_len;
++	}
++
++out:
++	/* return result of parse_bd_ie_board() or -ENOENT */
++	return ret;
++}
++
+ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
+ 					      const char *boardname,
++					      const char *fallback_boardname,
+ 					      const char *filename)
+ {
+-	size_t len, magic_len, ie_len;
+-	struct ath10k_fw_ie *hdr;
++	size_t len, magic_len;
+ 	const u8 *data;
+-	int ret, ie_id;
++	int ret;
+ 
+ 	ar->normal_mode_fw.board = ath10k_fetch_fw_file(ar,
+ 							ar->hw_params.fw.dir,
+@@ -1174,69 +1221,23 @@ static int ath10k_core_fetch_board_data_
+ 	data += magic_len;
+ 	len -= magic_len;
+ 
+-	while (len > sizeof(struct ath10k_fw_ie)) {
+-		hdr = (struct ath10k_fw_ie *)data;
+-		ie_id = le32_to_cpu(hdr->id);
+-		ie_len = le32_to_cpu(hdr->len);
+-
+-		len -= sizeof(*hdr);
+-		data = hdr->data;
+-
+-		if (len < ALIGN(ie_len, 4)) {
+-			ath10k_err(ar, "invalid length for board ie_id %d ie_len %zu len %zu\n",
+-				   ie_id, ie_len, len);
+-			ret = -EINVAL;
+-			goto err;
+-		}
++	/* attempt to find boardname in the IE list */
++	ret = ath10k_core_search_bd(ar, boardname, data, len);
+ 
+-		switch (ie_id) {
+-		case ATH10K_BD_IE_BOARD:
+-			ret = ath10k_core_parse_bd_ie_board(ar, data, ie_len,
+-							    boardname);
+-			if (ret == -ENOENT && ar->id.bdf_ext[0] != '\0') {
+-				/* try default bdf if variant was not found */
+-				char *s, *v = ",variant=";
+-				char boardname2[100];
+-
+-				strlcpy(boardname2, boardname,
+-					sizeof(boardname2));
+-
+-				s = strstr(boardname2, v);
+-				if (s)
+-					*s = '\0';  /* strip ",variant=%s" */
+-
+-				ret = ath10k_core_parse_bd_ie_board(ar, data,
+-								    ie_len,
+-								    boardname2);
+-			}
++	/* if we didn't find it and have a fallback name, try that */
++	if (ret == -ENOENT && fallback_boardname)
++		ret = ath10k_core_search_bd(ar, fallback_boardname, data, len);
+ 
+-			if (ret == -ENOENT)
+-				/* no match found, continue */
+-				break;
+-			else if (ret)
+-				/* there was an error, bail out */
+-				goto err;
+-
+-			/* board data found */
+-			goto out;
+-		}
+-
+-		/* jump over the padding */
+-		ie_len = ALIGN(ie_len, 4);
+-
+-		len -= ie_len;
+-		data += ie_len;
+-	}
+-
+-out:
+-	if (!ar->normal_mode_fw.board_data || !ar->normal_mode_fw.board_len) {
++	if (ret == -ENOENT) {
+ 		ath10k_err(ar,
+ 			   "failed to fetch board data for %s from %s/%s\n",
+ 			   boardname, ar->hw_params.fw.dir, filename);
+ 		ret = -ENODATA;
+-		goto err;
+ 	}
+ 
++	if (ret)
++		goto err;
++
+ 	return 0;
+ 
+ err:
+@@ -1245,12 +1246,12 @@ err:
+ }
+ 
+ static int ath10k_core_create_board_name(struct ath10k *ar, char *name,
+-					 size_t name_len)
++					 size_t name_len, bool with_variant)
+ {
+ 	/* strlen(',variant=') + strlen(ar->id.bdf_ext) */
+ 	char variant[9 + ATH10K_SMBIOS_BDF_EXT_STR_LENGTH] = { 0 };
+ 
+-	if (ar->id.bdf_ext[0] != '\0')
++	if (with_variant && ar->id.bdf_ext[0] != '\0')
+ 		scnprintf(variant, sizeof(variant), ",variant=%s",
+ 			  ar->id.bdf_ext);
+ 
+@@ -1276,17 +1277,26 @@ out:
+ 
+ static int ath10k_core_fetch_board_file(struct ath10k *ar)
+ {
+-	char boardname[100];
++	char boardname[100], fallback_boardname[100];
+ 	int ret;
+ 
+-	ret = ath10k_core_create_board_name(ar, boardname, sizeof(boardname));
++	ret = ath10k_core_create_board_name(ar, boardname,
++					    sizeof(boardname), true);
+ 	if (ret) {
+ 		ath10k_err(ar, "failed to create board name: %d", ret);
+ 		return ret;
+ 	}
+ 
++	ret = ath10k_core_create_board_name(ar, fallback_boardname,
++					    sizeof(boardname), false);
++	if (ret) {
++		ath10k_err(ar, "failed to create fallback board name: %d", ret);
++		return ret;
++	}
++
+ 	ar->bd_api = 2;
+ 	ret = ath10k_core_fetch_board_data_api_n(ar, boardname,
++						 fallback_boardname,
+ 						 ATH10K_BOARD_API2_FILE);
+ 	if (!ret)
+ 		goto success;