[dv,top_earlgrey] baudrate not configurable via configure_uart_agent

[dahooz]

Description

In chip_base_vseq.sv there is a function to configure the uart agents:

opentitan/hw/top_earlgrey/dv/env/seq_lib/chip_base_vseq.sv

Lines 233 to 253 in 6c72825

	virtual function void configure_uart_agent(int uart_idx,
	bit enable,
	bit enable_tx_monitor = 1'b1,
	bit enable_rx_monitor = 1'b0,
	bit en_parity = 1'b0,
	bit odd_parity = 1'b0,
	baud_rate_e baud_rate = cfg.uart_baud_rate);
	if (enable) begin
	`uvm_info(`gfn, $sformatf("Configuring and connecting UART%0d", uart_idx), UVM_LOW)
	cfg.m_uart_agent_cfgs[uart_idx].set_parity(en_parity, odd_parity);
	cfg.m_uart_agent_cfgs[uart_idx].set_baud_rate(cfg.uart_baud_rate);
	cfg.m_uart_agent_cfgs[uart_idx].en_tx_monitor = enable_tx_monitor;
	cfg.m_uart_agent_cfgs[uart_idx].en_rx_monitor = enable_rx_monitor;
	cfg.chip_vif.enable_uart(uart_idx, 1);
	end else begin
	`uvm_info(`gfn, $sformatf("Disconnecting UART%0d", uart_idx), UVM_LOW)
	cfg.m_uart_agent_cfgs[uart_idx].en_tx_monitor = 0;
	cfg.m_uart_agent_cfgs[uart_idx].en_rx_monitor = 0;
	cfg.chip_vif.enable_uart(uart_idx, 0);
	end
	endfunction

In Line 243, the function parameter is ignored, and the baudrate from chip_env_cfg is used. Thus, setting a different baudrate via function parameter has no effect.

Solution:

-      cfg.m_uart_agent_cfgs[uart_idx].set_baud_rate(cfg.uart_baud_rate);
+      cfg.m_uart_agent_cfgs[uart_idx].set_baud_rate(baud_rate);

This probably remained unnoticed, because baudrate testing in chip_sw_uart_rand_baudrate_vseq.sv uses chip_env_cfgs uart_baud_rate instead of the configure_uart_agent function:

https://github.com/lowRISC/opentitan/blob/master/hw/top_earlgrey/dv/env/seq_lib/chip_sw_uart_rand_baudrate_vseq.sv#L42-L45