2022-05-09 17:30:09

by Jeff Johnson

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

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 <[email protected]>
> ---
>
> 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;