ath10k: Fix the MTU size on QCA9377 SDIO

On an imx6dl-pico-pi board with a QCA9377 SDIO chip, simply trying to
connect via ssh to another machine causes:

[   55.824159] ath10k_sdio mmc1:0001:1: failed to transmit packet, dropping: -12
[   55.832169] ath10k_sdio mmc1:0001:1: failed to submit frame: -12
[   55.838529] ath10k_sdio mmc1:0001:1: failed to push frame: -12
[   55.905863] ath10k_sdio mmc1:0001:1: failed to transmit packet, dropping: -12
[   55.913650] ath10k_sdio mmc1:0001:1: failed to submit frame: -12
[   55.919887] ath10k_sdio mmc1:0001:1: failed to push frame: -12

, leading to an ssh connection failure.

One user inspected the size of frames on Wireshark and reported
the followig:

"I was able to narrow the issue down to the mtu. If I set the mtu for
the wlan0 device to 1486 instead of 1500, the issue does not happen.

The size of frames that I see on Wireshark is exactly 1500 after
setting it to 1486."

Clearing the HI_ACS_FLAGS_ALT_DATA_CREDIT_SIZE avoids the problem and
the ssh command works successfully after that.

Introduce a 'credit_size_workaround' field to ath10k_hw_params for
the QCA9377 SDIO, so that the HI_ACS_FLAGS_ALT_DATA_CREDIT_SIZE
is not set in this case.

Tested with QCA9377 SDIO with firmware WLAN.TF.1.1.1-00061-QCATFSWPZ-1.

Fixes: 2f918ea9 ("ath10k: enable alt data of TX path for sdio")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20211124131047.713756-1-festevam@denx.de

drivers/net/wireless/ath/ath10k/core.c

@@ -90,6 +90,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = true,
 		.dynamic_sar_support = false,
 	},
@@ -125,6 +126,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = true,
 		.dynamic_sar_support = false,
 	},
@@ -161,6 +163,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -191,6 +194,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.num_wds_entries = 0x20,
 		.uart_pin_workaround = true,
 		.tx_stats_over_pktlog = false,
+		.credit_size_workaround = false,
 		.bmi_large_size_download = true,
 		.supports_peer_stats_info = true,
 		.dynamic_sar_support = true,
@@ -227,6 +231,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -262,6 +267,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -297,6 +303,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -335,6 +342,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = true,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.supports_peer_stats_info = true,
 		.dynamic_sar_support = true,
@@ -377,6 +385,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -425,6 +434,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -470,6 +480,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -505,6 +516,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -542,6 +554,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = true,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -571,6 +584,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.ast_skid_limit = 0x10,
 		.num_wds_entries = 0x20,
 		.uart_pin_workaround = true,
+		.credit_size_workaround = true,
 		.dynamic_sar_support = false,
 	},
 	{
@@ -612,6 +626,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = false,
 		.hw_filter_reset_required = true,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = false,
 	},
@@ -640,6 +655,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 		.rri_on_ddr = true,
 		.hw_filter_reset_required = false,
 		.fw_diag_ce_download = false,
+		.credit_size_workaround = false,
 		.tx_stats_over_pktlog = false,
 		.dynamic_sar_support = true,
 	},
@@ -715,6 +731,7 @@ static void ath10k_send_suspend_complete(struct ath10k *ar)
 
 static int ath10k_init_sdio(struct ath10k *ar, enum ath10k_firmware_mode mode)
 {
+	bool mtu_workaround = ar->hw_params.credit_size_workaround;
 	int ret;
 	u32 param = 0;
 
@@ -732,7 +749,7 @@ static int ath10k_init_sdio(struct ath10k *ar, enum ath10k_firmware_mode mode)
 
 	param |= HI_ACS_FLAGS_SDIO_REDUCE_TX_COMPL_SET;
 
-	if (mode == ATH10K_FIRMWARE_MODE_NORMAL)
+	if (mode == ATH10K_FIRMWARE_MODE_NORMAL && !mtu_workaround)
 		param |= HI_ACS_FLAGS_ALT_DATA_CREDIT_SIZE;
 	else
 		param &= ~HI_ACS_FLAGS_ALT_DATA_CREDIT_SIZE;

drivers/net/wireless/ath/ath10k/hw.h

@@ -618,6 +618,9 @@ struct ath10k_hw_params {
 	 */
 	bool uart_pin_workaround;
 
+	/* Workaround for the credit size calculation */
+	bool credit_size_workaround;
+
 	/* tx stats support over pktlog */
 	bool tx_stats_over_pktlog;