ath10k: Fix the MTU size on QCA9377 SDIO

commit 09b8cd69edcf2be04a781e1781e98e52a775c9ad upstream.

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: 2f918ea986 ("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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -89,6 +89,7 @@ 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,
 	},
 	{
@@ -123,6 +124,7 @@ 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,
 	},
 	{
@@ -158,6 +160,7 @@ 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,
 	},
 	{
@@ -187,6 +190,7 @@ 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,
 	},
@@ -222,6 +226,7 @@ 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,
 	},
 	{
@@ -256,6 +261,7 @@ 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,
 	},
 	{
@@ -290,6 +296,7 @@ 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,
 	},
 	{
@@ -327,6 +334,7 @@ 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,
 	},
@@ -368,6 +376,7 @@ 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,
 	},
 	{
@@ -415,6 +424,7 @@ 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,
 	},
 	{
@@ -459,6 +469,7 @@ 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,
 	},
 	{
@@ -493,6 +504,7 @@ 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,
 	},
 	{
@@ -529,6 +541,7 @@ 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,
 	},
 	{
@@ -557,6 +570,7 @@ 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,
 	},
 	{
 		.id = QCA4019_HW_1_0_DEV_VERSION,
@@ -597,6 +611,7 @@ 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,
 	},
 	{
@@ -624,6 +639,7 @@ 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,
 	},
 };
@@ -697,6 +713,7 @@ 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;
 
@@ -714,7 +731,7 @@ 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;