[PATCH v3] ath10k: improve BDF search fallback strategy

[PATCH v3] ath10k: improve BDF search fallback strategy

[Abhishek Kumar]

Board data files wrapped inside board-2.bin files are
identified based on a combination of bus architecture,
chip-id, board-id or variants. Here is one such example
of a BDF entry in board-2.bin file:
bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
It is possible for few platforms none of the combinations
of bus,qmi-board,chip-id or variants match, e.g. if
board-id is not programmed and thus reads board-id=0xff,
there won't be any matching BDF to be found. In such
situations, the wlan will fail to enumerate.

Currently, to search for BDF, there are two fallback
boardnames creates to search for BDFs in case the full BDF
is not found. It is still possible that even the fallback
boardnames do not match.

As an improvement, search for BDF with full BDF combination
and perform the fallback searches by stripping down the last
elements until a BDF entry is found or none is found for all
possible BDF combinations.e.g.
Search for initial BDF first then followed by reduced BDF
names as follows:
bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
bus=snoc,qmi-board-id=67,qmi-chip-id=320
bus=snoc,qmi-board-id=67
bus=snoc
<No BDF found>

Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
---

Changes in v3:
- As discussed, instead of adding support for default BDF in DT, added
a method to drop the last elements from full BDF until a BDF is found.
- Previous patch was "ath10k: search for default BDF name provided in DT"

 drivers/net/wireless/ath/ath10k/core.c | 65 +++++++++++++-------------
 1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 688177453b07..ebb0d2a02c28 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -1426,15 +1426,31 @@ static int ath10k_core_search_bd(struct ath10k *ar,
 	return ret;
 }
 
+static bool ath10k_create_reduced_boardname(struct ath10k *ar, char *boardname)
+{
+	/* Find last BDF element */
+	char *last_field = strrchr(boardname, ',');
+
+	if (last_field) {
+		/* Drop the last BDF element */
+		last_field[0] = '\0';
+		ath10k_dbg(ar, ATH10K_DBG_BOOT,
+			   "boardname =%s\n", boardname);
+		return 0;
+	}
+	return -ENODATA;
+}
+
 static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
 					      const char *boardname,
-					      const char *fallback_boardname1,
-					      const char *fallback_boardname2,
 					      const char *filename)
 {
-	size_t len, magic_len;
+	size_t len, magic_len, board_len;
 	const u8 *data;
 	int ret;
+	char temp_boardname[100];
+
+	board_len = 100 * sizeof(temp_boardname[0]);
 
 	/* Skip if already fetched during board data download */
 	if (!ar->normal_mode_fw.board)
@@ -1474,20 +1490,24 @@ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
 	data += magic_len;
 	len -= magic_len;
 
-	/* attempt to find boardname in the IE list */
-	ret = ath10k_core_search_bd(ar, boardname, data, len);
+	memcpy(temp_boardname, boardname, board_len);
+	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boardname :%s\n", boardname);
 
-	/* if we didn't find it and have a fallback name, try that */
-	if (ret == -ENOENT && fallback_boardname1)
-		ret = ath10k_core_search_bd(ar, fallback_boardname1, data, len);
+retry_search:
+	/* attempt to find boardname in the IE list */
+	ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
 
-	if (ret == -ENOENT && fallback_boardname2)
-		ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
+	/* If the full BDF entry was not found then drop the last element and
+	 * recheck until a BDF is found or until all options are exhausted.
+	 */
+	if (ret == -ENOENT)
+		if (!ath10k_create_reduced_boardname(ar, temp_boardname))
+			goto retry_search;
 
 	if (ret == -ENOENT) {
 		ath10k_err(ar,
 			   "failed to fetch board data for %s from %s/%s\n",
-			   boardname, ar->hw_params.fw.dir, filename);
+			   temp_boardname, ar->hw_params.fw.dir, filename);
 		ret = -ENODATA;
 	}
 
@@ -1566,7 +1586,7 @@ static int ath10k_core_create_eboard_name(struct ath10k *ar, char *name,
 
 int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
 {
-	char boardname[100], fallback_boardname1[100], fallback_boardname2[100];
+	char boardname[100];
 	int ret;
 
 	if (bd_ie_type == ATH10K_BD_IE_BOARD) {
@@ -1579,25 +1599,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
 			return ret;
 		}
 
-		/* Without variant and only chip-id */
-		ret = ath10k_core_create_board_name(ar, fallback_boardname1,
-						    sizeof(boardname), false,
-						    true);
-		if (ret) {
-			ath10k_err(ar, "failed to create 1st fallback board name: %d",
-				   ret);
-			return ret;
-		}
-
-		/* Without variant and without chip-id */
-		ret = ath10k_core_create_board_name(ar, fallback_boardname2,
-						    sizeof(boardname), false,
-						    false);
-		if (ret) {
-			ath10k_err(ar, "failed to create 2nd fallback board name: %d",
-				   ret);
-			return ret;
-		}
 	} else if (bd_ie_type == ATH10K_BD_IE_BOARD_EXT) {
 		ret = ath10k_core_create_eboard_name(ar, boardname,
 						     sizeof(boardname));
@@ -1609,8 +1610,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
 
 	ar->bd_api = 2;
 	ret = ath10k_core_fetch_board_data_api_n(ar, boardname,
-						 fallback_boardname1,
-						 fallback_boardname2,
 						 ATH10K_BOARD_API2_FILE);
 	if (!ret)
 		goto success;
-- 
2.36.0.512.ge40c2bad7a-goog

Re: [PATCH v3] ath10k: improve BDF search fallback strategy

[Jeff Johnson]

On 5/8/2022 7:26 PM, Abhishek Kumar wrote:
> Board data files wrapped inside board-2.bin files are
> identified based on a combination of bus architecture,
> chip-id, board-id or variants. Here is one such example
> of a BDF entry in board-2.bin file:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> It is possible for few platforms none of the combinations
> of bus,qmi-board,chip-id or variants match, e.g. if
> board-id is not programmed and thus reads board-id=0xff,
> there won't be any matching BDF to be found. In such
> situations, the wlan will fail to enumerate.
> 
> Currently, to search for BDF, there are two fallback
> boardnames creates to search for BDFs in case the full BDF
> is not found. It is still possible that even the fallback
> boardnames do not match.
> 
> As an improvement, search for BDF with full BDF combination
> and perform the fallback searches by stripping down the last
> elements until a BDF entry is found or none is found for all
> possible BDF combinations.e.g.
> Search for initial BDF first then followed by reduced BDF
> names as follows:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> bus=snoc,qmi-board-id=67,qmi-chip-id=320
> bus=snoc,qmi-board-id=67
> bus=snoc
> <No BDF found>
> 
> Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
> Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
> ---
> 
> Changes in v3:
> - As discussed, instead of adding support for default BDF in DT, added
> a method to drop the last elements from full BDF until a BDF is found.
> - Previous patch was "ath10k: search for default BDF name provided in DT"
> 
>   drivers/net/wireless/ath/ath10k/core.c | 65 +++++++++++++-------------
>   1 file changed, 32 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 688177453b07..ebb0d2a02c28 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -1426,15 +1426,31 @@ static int ath10k_core_search_bd(struct ath10k *ar,
>   	return ret;
>   }
>   
> +static bool ath10k_create_reduced_boardname(struct ath10k *ar, char *boardname)
> +{
> +	/* Find last BDF element */
> +	char *last_field = strrchr(boardname, ',');
> +
> +	if (last_field) {
> +		/* Drop the last BDF element */
> +		last_field[0] = '\0';
> +		ath10k_dbg(ar, ATH10K_DBG_BOOT,
> +			   "boardname =%s\n", boardname);

nit: strange spacing in the message. i'd expect consistent spacing on 
both side of "=", either one space on both sides or no space on both 
sides.  also the use of "=" here is inconsistent with the use of ":" in 
a log later below

> +		return 0;
> +	}
> +	return -ENODATA;
> +}
> +
>   static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>   					      const char *boardname,
> -					      const char *fallback_boardname1,
> -					      const char *fallback_boardname2,
>   					      const char *filename)
>   {
> -	size_t len, magic_len;
> +	size_t len, magic_len, board_len;
>   	const u8 *data;
>   	int ret;
> +	char temp_boardname[100];
> +
> +	board_len = 100 * sizeof(temp_boardname[0]);
>   
>   	/* Skip if already fetched during board data download */
>   	if (!ar->normal_mode_fw.board)
> @@ -1474,20 +1490,24 @@ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>   	data += magic_len;
>   	len -= magic_len;
>   
> -	/* attempt to find boardname in the IE list */
> -	ret = ath10k_core_search_bd(ar, boardname, data, len);
> +	memcpy(temp_boardname, boardname, board_len);
> +	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boardname :%s\n", boardname);

nit: use of ":" inconsistent with use of "=" noted above.
also expect space after ":, not before: "boardname: %s\n"


>   
> -	/* if we didn't find it and have a fallback name, try that */
> -	if (ret == -ENOENT && fallback_boardname1)
> -		ret = ath10k_core_search_bd(ar, fallback_boardname1, data, len);
> +retry_search:
> +	/* attempt to find boardname in the IE list */
> +	ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
>   
> -	if (ret == -ENOENT && fallback_boardname2)
> -		ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
> +	/* If the full BDF entry was not found then drop the last element and
> +	 * recheck until a BDF is found or until all options are exhausted.
> +	 */
> +	if (ret == -ENOENT)
> +		if (!ath10k_create_reduced_boardname(ar, temp_boardname))
> +			goto retry_search;
>   
>   	if (ret == -ENOENT) {

note that ath10k_create_reduced_boardname() returns -ENODATA when 
truncation fails and hence you won't log this error when that occurs

>   		ath10k_err(ar,
>   			   "failed to fetch board data for %s from %s/%s\n",
> -			   boardname, ar->hw_params.fw.dir, filename);
> +			   temp_boardname, ar->hw_params.fw.dir, filename);

does it really make sense to log the last name tried, temp_boardname? or 
does it make more sense to still log the original name, boardname?

maybe log each failure in the loop, before calling 
ath10k_create_reduced_boardname()?

>   		ret = -ENODATA;
>   	}
>   
> @@ -1566,7 +1586,7 @@ static int ath10k_core_create_eboard_name(struct ath10k *ar, char *name,
>   
>   int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>   {
> -	char boardname[100], fallback_boardname1[100], fallback_boardname2[100];
> +	char boardname[100];
>   	int ret;
>   
>   	if (bd_ie_type == ATH10K_BD_IE_BOARD) {
> @@ -1579,25 +1599,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>   			return ret;
>   		}
>   
> -		/* Without variant and only chip-id */
> -		ret = ath10k_core_create_board_name(ar, fallback_boardname1,
> -						    sizeof(boardname), false,
> -						    true);
> -		if (ret) {
> -			ath10k_err(ar, "failed to create 1st fallback board name: %d",
> -				   ret);
> -			return ret;
> -		}
> -
> -		/* Without variant and without chip-id */
> -		ret = ath10k_core_create_board_name(ar, fallback_boardname2,
> -						    sizeof(boardname), false,
> -						    false);
> -		if (ret) {
> -			ath10k_err(ar, "failed to create 2nd fallback board name: %d",
> -				   ret);
> -			return ret;
> -		}
>   	} else if (bd_ie_type == ATH10K_BD_IE_BOARD_EXT) {
>   		ret = ath10k_core_create_eboard_name(ar, boardname,
>   						     sizeof(boardname));
> @@ -1609,8 +1610,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>   
>   	ar->bd_api = 2;
>   	ret = ath10k_core_fetch_board_data_api_n(ar, boardname,
> -						 fallback_boardname1,
> -						 fallback_boardname2,
>   						 ATH10K_BOARD_API2_FILE);
>   	if (!ret)
>   		goto success;

Re: [PATCH v3] ath10k: improve BDF search fallback strategy

[Abhishek Kumar]

Replying again ...

Thanks for the review Jeff, I have replied below and will address
these comments in next iteration. I will wait for a day more to get
some more reviews and collectively make the change.

On Mon, May 9, 2022 at 10:22 AM Jeff Johnson <quic_jjohnson@quicinc.com> wrote:
>
> On 5/8/2022 7:26 PM, Abhishek Kumar wrote:
> > Board data files wrapped inside board-2.bin files are
> > identified based on a combination of bus architecture,
> > chip-id, board-id or variants. Here is one such example
> > of a BDF entry in board-2.bin file:
> > bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> > It is possible for few platforms none of the combinations
> > of bus,qmi-board,chip-id or variants match, e.g. if
> > board-id is not programmed and thus reads board-id=0xff,
> > there won't be any matching BDF to be found. In such
> > situations, the wlan will fail to enumerate.
> >
> > Currently, to search for BDF, there are two fallback
> > boardnames creates to search for BDFs in case the full BDF
> > is not found. It is still possible that even the fallback
> > boardnames do not match.
> >
> > As an improvement, search for BDF with full BDF combination
> > and perform the fallback searches by stripping down the last
> > elements until a BDF entry is found or none is found for all
> > possible BDF combinations.e.g.
> > Search for initial BDF first then followed by reduced BDF
> > names as follows:
> > bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> > bus=snoc,qmi-board-id=67,qmi-chip-id=320
> > bus=snoc,qmi-board-id=67
> > bus=snoc
> > <No BDF found>
> >
> > Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
> > Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
> > ---
> >
> > Changes in v3:
> > - As discussed, instead of adding support for default BDF in DT, added
> > a method to drop the last elements from full BDF until a BDF is found.
> > - Previous patch was "ath10k: search for default BDF name provided in DT"
> >
> >   drivers/net/wireless/ath/ath10k/core.c | 65 +++++++++++++-------------
> >   1 file changed, 32 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> > index 688177453b07..ebb0d2a02c28 100644
> > --- a/drivers/net/wireless/ath/ath10k/core.c
> > +++ b/drivers/net/wireless/ath/ath10k/core.c
> > @@ -1426,15 +1426,31 @@ static int ath10k_core_search_bd(struct ath10k *ar,
> >       return ret;
> >   }
> >
> > +static bool ath10k_create_reduced_boardname(struct ath10k *ar, char *boardname)
> > +{
> > +     /* Find last BDF element */
> > +     char *last_field = strrchr(boardname, ',');
> > +
> > +     if (last_field) {
> > +             /* Drop the last BDF element */
> > +             last_field[0] = '\0';
> > +             ath10k_dbg(ar, ATH10K_DBG_BOOT,
> > +                        "boardname =%s\n", boardname);
>
> nit: strange spacing in the message. i'd expect consistent spacing on
> both side of "=", either one space on both sides or no space on both
> sides.  also the use of "=" here is inconsistent with the use of ":" in
> a log later below

Ack, will fix this in the next iteration.
>
>
> > +             return 0;
> > +     }
> > +     return -ENODATA;
> > +}
> > +
> >   static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
> >                                             const char *boardname,
> > -                                           const char *fallback_boardname1,
> > -                                           const char *fallback_boardname2,
> >                                             const char *filename)
> >   {
> > -     size_t len, magic_len;
> > +     size_t len, magic_len, board_len;
> >       const u8 *data;
> >       int ret;
> > +     char temp_boardname[100];
> > +
> > +     board_len = 100 * sizeof(temp_boardname[0]);
> >
> >       /* Skip if already fetched during board data download */
> >       if (!ar->normal_mode_fw.board)
> > @@ -1474,20 +1490,24 @@ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
> >       data += magic_len;
> >       len -= magic_len;
> >
> > -     /* attempt to find boardname in the IE list */
> > -     ret = ath10k_core_search_bd(ar, boardname, data, len);
> > +     memcpy(temp_boardname, boardname, board_len);
> > +     ath10k_dbg(ar, ATH10K_DBG_BOOT, "boardname :%s\n", boardname);
>
> nit: use of ":" inconsistent with use of "=" noted above.
> also expect space after ":, not before: "boardname: %s\n"
>
Ack, will remove the extra space.
>
>
> >
> > -     /* if we didn't find it and have a fallback name, try that */
> > -     if (ret == -ENOENT && fallback_boardname1)
> > -             ret = ath10k_core_search_bd(ar, fallback_boardname1, data, len);
> > +retry_search:
> > +     /* attempt to find boardname in the IE list */
> > +     ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
> >
> > -     if (ret == -ENOENT && fallback_boardname2)
> > -             ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
> > +     /* If the full BDF entry was not found then drop the last element and
> > +      * recheck until a BDF is found or until all options are exhausted.
> > +      */
> > +     if (ret == -ENOENT)
> > +             if (!ath10k_create_reduced_boardname(ar, temp_boardname))
> > +                     goto retry_search;
> >
> >       if (ret == -ENOENT) {
>
> note that ath10k_create_reduced_boardname() returns -ENODATA when
> truncation fails and hence you won't log this error when that occurs

Hmmm, I think it makes sense to log each failure to find as a debug
log and log as err only if nothing matches (when ENODATA is returned).
>
>
> >               ath10k_err(ar,
> >                          "failed to fetch board data for %s from %s/%s\n",
> > -                        boardname, ar->hw_params.fw.dir, filename);
> > +                        temp_boardname, ar->hw_params.fw.dir, filename);
>
> does it really make sense to log the last name tried, temp_boardname? or
> does it make more sense to still log the original name, boardname?

Thinking about it a bit more, it makes sense to log the original name
rather than last name.
>
>
> maybe log each failure in the loop, before calling
> ath10k_create_reduced_boardname()?

As mentioned above, it makes sense to log as debug for each failure to
find and log as error if nothing matches, will make this change in the
next iteration.

>               ret = -ENODATA;
>       }
>
> @@ -1566,7 +1586,7 @@ static int ath10k_core_create_eboard_name(struct ath10k *ar, char *name,
>
>   int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>   {
> -     char boardname[100], fallback_boardname1[100], fallback_boardname2[100];
> +     char boardname[100];
>       int ret;
>
>       if (bd_ie_type == ATH10K_BD_IE_BOARD) {
> @@ -1579,25 +1599,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>                       return ret;
>               }
>
> -             /* Without variant and only chip-id */
> -             ret = ath10k_core_create_board_name(ar, fallback_boardname1,
> -                                                 sizeof(boardname), false,
> -                                                 true);
> -             if (ret) {
> -                     ath10k_err(ar, "failed to create 1st fallback board name: %d",
> -                                ret);
> -                     return ret;
> -             }
> -
> -             /* Without variant and without chip-id */
> -             ret = ath10k_core_create_board_name(ar, fallback_boardname2,
> -                                                 sizeof(boardname), false,
> -                                                 false);
> -             if (ret) {
> -                     ath10k_err(ar, "failed to create 2nd fallback board name: %d",
> -                                ret);
> -                     return ret;
> -             }
>       } else if (bd_ie_type == ATH10K_BD_IE_BOARD_EXT) {
>               ret = ath10k_core_create_eboard_name(ar, boardname,
>                                                    sizeof(boardname));
> @@ -1609,8 +1610,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>
>       ar->bd_api = 2;
>       ret = ath10k_core_fetch_board_data_api_n(ar, boardname,
> -                                              fallback_boardname1,
> -                                              fallback_boardname2,
>                                                ATH10K_BOARD_API2_FILE);
>       if (!ret)
>               goto success;
-Abhishek

On Mon, May 9, 2022 at 7:04 PM Abhishek Kumar <kuabhs@google.com> wrote:
>
> Thanks for the review Jeff, I have replied below and will address these comments in next iteration. I will wait for a day more to get some more reviews and collectively make the change.
>
> On Mon, May 9, 2022 at 10:22 AM Jeff Johnson <quic_jjohnson@quicinc.com> wrote:
>>
>> On 5/8/2022 7:26 PM, Abhishek Kumar wrote:
>> > Board data files wrapped inside board-2.bin files are
>> > identified based on a combination of bus architecture,
>> > chip-id, board-id or variants. Here is one such example
>> > of a BDF entry in board-2.bin file:
>> > bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
>> > It is possible for few platforms none of the combinations
>> > of bus,qmi-board,chip-id or variants match, e.g. if
>> > board-id is not programmed and thus reads board-id=0xff,
>> > there won't be any matching BDF to be found. In such
>> > situations, the wlan will fail to enumerate.
>> >
>> > Currently, to search for BDF, there are two fallback
>> > boardnames creates to search for BDFs in case the full BDF
>> > is not found. It is still possible that even the fallback
>> > boardnames do not match.
>> >
>> > As an improvement, search for BDF with full BDF combination
>> > and perform the fallback searches by stripping down the last
>> > elements until a BDF entry is found or none is found for all
>> > possible BDF combinations.e.g.
>> > Search for initial BDF first then followed by reduced BDF
>> > names as follows:
>> > bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
>> > bus=snoc,qmi-board-id=67,qmi-chip-id=320
>> > bus=snoc,qmi-board-id=67
>> > bus=snoc
>> > <No BDF found>
>> >
>> > Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
>> > Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
>> > ---
>> >
>> > Changes in v3:
>> > - As discussed, instead of adding support for default BDF in DT, added
>> > a method to drop the last elements from full BDF until a BDF is found.
>> > - Previous patch was "ath10k: search for default BDF name provided in DT"
>> >
>> >   drivers/net/wireless/ath/ath10k/core.c | 65 +++++++++++++-------------
>> >   1 file changed, 32 insertions(+), 33 deletions(-)
>> >
>> > diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
>> > index 688177453b07..ebb0d2a02c28 100644
>> > --- a/drivers/net/wireless/ath/ath10k/core.c
>> > +++ b/drivers/net/wireless/ath/ath10k/core.c
>> > @@ -1426,15 +1426,31 @@ static int ath10k_core_search_bd(struct ath10k *ar,
>> >       return ret;
>> >   }
>> >
>> > +static bool ath10k_create_reduced_boardname(struct ath10k *ar, char *boardname)
>> > +{
>> > +     /* Find last BDF element */
>> > +     char *last_field = strrchr(boardname, ',');
>> > +
>> > +     if (last_field) {
>> > +             /* Drop the last BDF element */
>> > +             last_field[0] = '\0';
>> > +             ath10k_dbg(ar, ATH10K_DBG_BOOT,
>> > +                        "boardname =%s\n", boardname);
>>
>> nit: strange spacing in the message. i'd expect consistent spacing on
>> both side of "=", either one space on both sides or no space on both
>> sides.  also the use of "=" here is inconsistent with the use of ":" in
>> a log later below
>
> Ack, will fix this in the next iteration.
>>
>>
>> > +             return 0;
>> > +     }
>> > +     return -ENODATA;
>> > +}
>> > +
>> >   static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>> >                                             const char *boardname,
>> > -                                           const char *fallback_boardname1,
>> > -                                           const char *fallback_boardname2,
>> >                                             const char *filename)
>> >   {
>> > -     size_t len, magic_len;
>> > +     size_t len, magic_len, board_len;
>> >       const u8 *data;
>> >       int ret;
>> > +     char temp_boardname[100];
>> > +
>> > +     board_len = 100 * sizeof(temp_boardname[0]);
>> >
>> >       /* Skip if already fetched during board data download */
>> >       if (!ar->normal_mode_fw.board)
>> > @@ -1474,20 +1490,24 @@ static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>> >       data += magic_len;
>> >       len -= magic_len;
>> >
>> > -     /* attempt to find boardname in the IE list */
>> > -     ret = ath10k_core_search_bd(ar, boardname, data, len);
>> > +     memcpy(temp_boardname, boardname, board_len);
>> > +     ath10k_dbg(ar, ATH10K_DBG_BOOT, "boardname :%s\n", boardname);
>>
>> nit: use of ":" inconsistent with use of "=" noted above.
>> also expect space after ":, not before: "boardname: %s\n"
>>
> Ack, will remove the extra space.
>>
>>
>> >
>> > -     /* if we didn't find it and have a fallback name, try that */
>> > -     if (ret == -ENOENT && fallback_boardname1)
>> > -             ret = ath10k_core_search_bd(ar, fallback_boardname1, data, len);
>> > +retry_search:
>> > +     /* attempt to find boardname in the IE list */
>> > +     ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
>> >
>> > -     if (ret == -ENOENT && fallback_boardname2)
>> > -             ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
>> > +     /* If the full BDF entry was not found then drop the last element and
>> > +      * recheck until a BDF is found or until all options are exhausted.
>> > +      */
>> > +     if (ret == -ENOENT)
>> > +             if (!ath10k_create_reduced_boardname(ar, temp_boardname))
>> > +                     goto retry_search;
>> >
>> >       if (ret == -ENOENT) {
>>
>> note that ath10k_create_reduced_boardname() returns -ENODATA when
>> truncation fails and hence you won't log this error when that occurs
>
> Hmmm, I think it makes sense to log each failure to find as a debug log and log as err only if nothing matches (when ENODATA is returned).
>>
>>
>> >               ath10k_err(ar,
>> >                          "failed to fetch board data for %s from %s/%s\n",
>> > -                        boardname, ar->hw_params.fw.dir, filename);
>> > +                        temp_boardname, ar->hw_params.fw.dir, filename);
>>
>> does it really make sense to log the last name tried, temp_boardname? or
>> does it make more sense to still log the original name, boardname?
>
> Thinking about it a bit more, it makes sense to log the original name rather than last name.
>>
>>
>> maybe log each failure in the loop, before calling
>> ath10k_create_reduced_boardname()?
>
> As mentioned above, it makes sense to log as debug for each failure to find and log as error if nothing matches, will make this change in next iteration.
>>
>>
>> >               ret = -ENODATA;
>> >       }
>> >
>> > @@ -1566,7 +1586,7 @@ static int ath10k_core_create_eboard_name(struct ath10k *ar, char *name,
>> >
>> >   int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>> >   {
>> > -     char boardname[100], fallback_boardname1[100], fallback_boardname2[100];
>> > +     char boardname[100];
>> >       int ret;
>> >
>> >       if (bd_ie_type == ATH10K_BD_IE_BOARD) {
>> > @@ -1579,25 +1599,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>> >                       return ret;
>> >               }
>> >
>> > -             /* Without variant and only chip-id */
>> > -             ret = ath10k_core_create_board_name(ar, fallback_boardname1,
>> > -                                                 sizeof(boardname), false,
>> > -                                                 true);
>> > -             if (ret) {
>> > -                     ath10k_err(ar, "failed to create 1st fallback board name: %d",
>> > -                                ret);
>> > -                     return ret;
>> > -             }
>> > -
>> > -             /* Without variant and without chip-id */
>> > -             ret = ath10k_core_create_board_name(ar, fallback_boardname2,
>> > -                                                 sizeof(boardname), false,
>> > -                                                 false);
>> > -             if (ret) {
>> > -                     ath10k_err(ar, "failed to create 2nd fallback board name: %d",
>> > -                                ret);
>> > -                     return ret;
>> > -             }
>> >       } else if (bd_ie_type == ATH10K_BD_IE_BOARD_EXT) {
>> >               ret = ath10k_core_create_eboard_name(ar, boardname,
>> >                                                    sizeof(boardname));
>> > @@ -1609,8 +1610,6 @@ int ath10k_core_fetch_board_file(struct ath10k *ar, int bd_ie_type)
>> >
>> >       ar->bd_api = 2;
>> >       ret = ath10k_core_fetch_board_data_api_n(ar, boardname,
>> > -                                              fallback_boardname1,
>> > -                                              fallback_boardname2,
>> >                                                ATH10K_BOARD_API2_FILE);
>> >       if (!ret)
>> >               goto success;
>
> -Abhishek

Re: [PATCH v3] ath10k: improve BDF search fallback strategy

[Kalle Valo]

Abhishek Kumar <kuabhs@chromium.org> writes:

> Board data files wrapped inside board-2.bin files are
> identified based on a combination of bus architecture,
> chip-id, board-id or variants. Here is one such example
> of a BDF entry in board-2.bin file:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> It is possible for few platforms none of the combinations
> of bus,qmi-board,chip-id or variants match, e.g. if
> board-id is not programmed and thus reads board-id=0xff,
> there won't be any matching BDF to be found. In such
> situations, the wlan will fail to enumerate.
>
> Currently, to search for BDF, there are two fallback
> boardnames creates to search for BDFs in case the full BDF
> is not found. It is still possible that even the fallback
> boardnames do not match.
>
> As an improvement, search for BDF with full BDF combination
> and perform the fallback searches by stripping down the last
> elements until a BDF entry is found or none is found for all
> possible BDF combinations.e.g.
> Search for initial BDF first then followed by reduced BDF
> names as follows:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> bus=snoc,qmi-board-id=67,qmi-chip-id=320
> bus=snoc,qmi-board-id=67
> bus=snoc
> <No BDF found>
>
> Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
> Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>

[...]

>  static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>  					      const char *boardname,
> -					      const char *fallback_boardname1,
> -					      const char *fallback_boardname2,
>  					      const char *filename)
>  {
> -	size_t len, magic_len;
> +	size_t len, magic_len, board_len;
>  	const u8 *data;
>  	int ret;
> +	char temp_boardname[100];
> +
> +	board_len = 100 * sizeof(temp_boardname[0]);

Why not:

board_len = sizeof(temp_board-name);

That way number 100 is used only once.

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Re: [PATCH v3] ath10k: improve BDF search fallback strategy

[Kalle Valo]

Kalle Valo <kvalo@kernel.org> writes:

>>  static int ath10k_core_fetch_board_data_api_n(struct ath10k *ar,
>>  					      const char *boardname,
>> -					      const char *fallback_boardname1,
>> -					      const char *fallback_boardname2,
>>  					      const char *filename)
>>  {
>> -	size_t len, magic_len;
>> +	size_t len, magic_len, board_len;
>>  	const u8 *data;
>>  	int ret;
>> +	char temp_boardname[100];
>> +
>> +	board_len = 100 * sizeof(temp_boardname[0]);
>
> Why not:
>
> board_len = sizeof(temp_board-name);
>
> That way number 100 is used only once.

BTW I'm not sure if it makes sense to CC David, Eric, Jakub and Paolo.
I'm sure they get a lot of email already. And I would also drop netdev.

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Re: [PATCH v3] ath10k: improve BDF search fallback strategy

[Kalle Valo]

Abhishek Kumar <kuabhs@chromium.org> writes:

> Board data files wrapped inside board-2.bin files are
> identified based on a combination of bus architecture,
> chip-id, board-id or variants. Here is one such example
> of a BDF entry in board-2.bin file:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> It is possible for few platforms none of the combinations
> of bus,qmi-board,chip-id or variants match, e.g. if
> board-id is not programmed and thus reads board-id=0xff,
> there won't be any matching BDF to be found. In such
> situations, the wlan will fail to enumerate.
>
> Currently, to search for BDF, there are two fallback
> boardnames creates to search for BDFs in case the full BDF
> is not found. It is still possible that even the fallback
> boardnames do not match.
>
> As an improvement, search for BDF with full BDF combination
> and perform the fallback searches by stripping down the last
> elements until a BDF entry is found or none is found for all
> possible BDF combinations.e.g.
> Search for initial BDF first then followed by reduced BDF
> names as follows:
> bus=snoc,qmi-board-id=67,qmi-chip-id=320,variant=GO_XXXX
> bus=snoc,qmi-board-id=67,qmi-chip-id=320
> bus=snoc,qmi-board-id=67
> bus=snoc
> <No BDF found>
>
> Tested-on: WCN3990/hw1.0 WLAN.HL.3.2.2.c10-00754-QCAHLSWMTPL-1
> Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
> ---
>
> Changes in v3:
> - As discussed, instead of adding support for default BDF in DT, added
> a method to drop the last elements from full BDF until a BDF is found.
> - Previous patch was "ath10k: search for default BDF name provided in DT"
>
>  drivers/net/wireless/ath/ath10k/core.c | 65 +++++++++++++-------------
>  1 file changed, 32 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 688177453b07..ebb0d2a02c28 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -1426,15 +1426,31 @@ static int ath10k_core_search_bd(struct ath10k *ar,
>  	return ret;
>  }
>  
> +static bool ath10k_create_reduced_boardname(struct ath10k *ar, char *boardname)


"static int" as you use error values. Strange that the compiler doesn't
warn about that.

> +{
> +	/* Find last BDF element */
> +	char *last_field = strrchr(boardname, ',');
> +
> +	if (last_field) {
> +		/* Drop the last BDF element */
> +		last_field[0] = '\0';
> +		ath10k_dbg(ar, ATH10K_DBG_BOOT,
> +			   "boardname =%s\n", boardname);
> +		return 0;
> +	}
> +	return -ENODATA;

I would invert the check:

	if (!last_field)
        	return -ENODATA;

	/* Drop the last BDF element */
	last_field[0] = '\0';
	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot reduced boardname %s\n",
		   boardname);

	return 0;

Also I changed the style used in the debug message.

https://wireless.wiki.kernel.org/en/users/drivers/ath10k/codingstyle#debug_messages

>  	data += magic_len;
>  	len -= magic_len;
>  
> -	/* attempt to find boardname in the IE list */
> -	ret = ath10k_core_search_bd(ar, boardname, data, len);
> +	memcpy(temp_boardname, boardname, board_len);
> +	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boardname :%s\n", boardname);

"boot boardname %s\n"

>  
> -	/* if we didn't find it and have a fallback name, try that */
> -	if (ret == -ENOENT && fallback_boardname1)
> -		ret = ath10k_core_search_bd(ar, fallback_boardname1, data, len);
> +retry_search:
> +	/* attempt to find boardname in the IE list */
> +	ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
>  
> -	if (ret == -ENOENT && fallback_boardname2)
> -		ret = ath10k_core_search_bd(ar, fallback_boardname2, data, len);
> +	/* If the full BDF entry was not found then drop the last element and
> +	 * recheck until a BDF is found or until all options are exhausted.
> +	 */
> +	if (ret == -ENOENT)
> +		if (!ath10k_create_reduced_boardname(ar, temp_boardname))
> +			goto retry_search;
>  
>  	if (ret == -ENOENT) {
>  		ath10k_err(ar,
>  			   "failed to fetch board data for %s from %s/%s\n",
> -			   boardname, ar->hw_params.fw.dir, filename);
> +			   temp_boardname, ar->hw_params.fw.dir, filename);
>  		ret = -ENODATA;
>  	}

This is hard to read, what about the loop below? Though I'm sure I
missed some corner case but I hope you get the idea. It's always good to
have a limit for the loops to avoid looping forever.

	for (i = 0; i < 20; i++) {
		/* attempt to find boardname in the IE list */
		ret = ath10k_core_search_bd(ar, temp_boardname, data, len);
		if (ret != -ENOENT)
			/* found it or something was wrong */
			break;

		/* If the full BDF entry was not found then drop the last element and
		 * recheck until a BDF is found or until all options are exhausted.
		 */
		ret = ath10k_create_reduced_boardname(ar, temp_boardname);
		if (ret) {
			ath10k_err(ar,
				   "failed to fetch board data for %s from %s/%s\n",
				   temp_boardname, ar->hw_params.fw.dir, filename);
			ret = -ENODATA;
			break;
		}
	};

	if (ret)
		goto err;

        return 0;

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