The electrical serdes configuration for USB3 expects an array as data argument. For USB3 the second value is used (see data_arr_idx = USB3 = 1). However, because only one value is inside the array mv_seq_exec is accessing an invalid element and the serdes is configured wrongly.
This wrong initialization is leading to an unreliable detection mechanism for some USB3 devices. We were able to reproduce the issue regularly with an LTE modem from Sierra Wireless (SM7455) where it was not detected as USB3 device in 1/3 of all tests.
This commit fixes the issue by setting data_arr_idx to 0. This is the same value as the original U-Boot from Marvell is using. There it is called FIRST_CELL which is a define for 0. See: https://github.com/MarvellEmbeddedProcessors/u-boot-marvell commit 56f963ce4c ("fix: serdes: a38x, a39x: Fix USB3 serdes DB initialization")
Signed-off-by: Stefan Eichenberger eichest@gmail.com Signed-off-by: René Straub rene.straub@netmodule.com --- arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c index d2bc3ab25c..11b5824232 100644 --- a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c +++ b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c @@ -1204,7 +1204,7 @@ int hws_serdes_seq_db_init(void) sizeof(usb3_electrical_config_serdes_rev2_params) / sizeof(struct op_params); } - serdes_seq_db[USB3_ELECTRICAL_CONFIG_SEQ].data_arr_idx = USB3; + serdes_seq_db[USB3_ELECTRICAL_CONFIG_SEQ].data_arr_idx = 0;
/* USB3_TX_CONFIG_SEQ sequence init */ serdes_seq_db[USB3_TX_CONFIG_SEQ1].op_params_ptr =