From e18eb03c4fbabb8ecf4a83c0cbafd19e2ed4c794 Mon Sep 17 00:00:00 2001 From: Daniel Jobson Date: Thu, 14 Nov 2024 14:02:53 +0100 Subject: [PATCH] PoC: Automatically control system_mode in hardware MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of manually switching to app mode using the system mode register, app mode will be enabled when executing outside of firmware ROM. Co-authored-by: Mikael Ågren --- hw/application_fpga/core/tk1/rtl/tk1.v | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/hw/application_fpga/core/tk1/rtl/tk1.v b/hw/application_fpga/core/tk1/rtl/tk1.v index 67f2131..103633b 100644 --- a/hw/application_fpga/core/tk1/rtl/tk1.v +++ b/hw/application_fpga/core/tk1/rtl/tk1.v @@ -107,6 +107,7 @@ module tk1 #( localparam FW_RAM_FIRST = 32'hd0000000; localparam FW_RAM_LAST = 32'hd00007ff; + localparam FW_ROM_LAST = 32'h000017ff; //---------------------------------------------------------------- // Registers including update variables and write enable. @@ -115,6 +116,7 @@ module tk1 #( reg cdi_mem_we; reg system_mode_reg; + reg system_mode_new; reg system_mode_we; reg [ 2 : 0] led_reg; @@ -291,7 +293,7 @@ module tk1 #( gpio2_reg[1] <= gpio2_reg[0]; if (system_mode_we) begin - system_mode_reg <= 1'h1; + system_mode_reg <= system_mode_new; end if (led_we) begin @@ -473,12 +475,27 @@ module tk1 #( end end + //---------------------------------------------------------------- + // system_mode_ctrl + // + // Automatically lower privilege when executing above ROM. + // ---------------------------------------------------------------- + always @* begin : system_mode_ctrl + system_mode_new = 1'h0; + system_mode_we = 1'h0; + + if (cpu_valid & cpu_instr) begin + if (cpu_addr > FW_ROM_LAST) begin + system_mode_new = 1'h1; + system_mode_we = 1'h1; + end + end + end //---------------------------------------------------------------- // api //---------------------------------------------------------------- always @* begin : api - system_mode_we = 1'h0; led_we = 1'h0; gpio3_we = 1'h0; gpio4_we = 1'h0; @@ -505,10 +522,6 @@ module tk1 #( if (cs) begin tmp_ready = 1'h1; if (we) begin - if (address == ADDR_SYSTEM_MODE_CTRL) begin - system_mode_we = 1'h1; - end - if (address == ADDR_LED) begin led_we = 1'h1; end