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fpga: Automatically control app_mode in hardware

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Instead of manually switching to app mode using the APP_MODE register,
app mode will be enabled when the CPU fetches an instruction outside of
firmware ROM.

Co-authored-by: Mikael Ågren <mikael@tillitis.se>
This commit is contained in:
Daniel Jobson 2024-11-14 14:02:53 +01:00 committed by Mikael Ågren
parent 97de5e68fd
commit 24ef39b739
No known key found for this signature in database
GPG Key ID: E02DA3D397792C46
1 changed files with 19 additions and 6 deletions
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25
hw/application_fpga/core/tk1/rtl/tk1.v
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@ -109,6 +109,7 @@ module tk1 #(
localparam FW_RAM_FIRST = 32'hd0000000;
localparam FW_RAM_LAST = 32'hd0000fff; // 4 KB
localparam FW_ROM_LAST = 32'h00001fff;
//----------------------------------------------------------------
// Registers including update variables and write enable.
@ -117,6 +118,7 @@ module tk1 #(
reg cdi_mem_we;
reg app_mode_reg;
reg app_mode_new;
reg app_mode_we;
reg [ 2 : 0] led_reg;
@ -292,7 +294,7 @@ module tk1 #(
gpio2_reg[1] <= gpio2_reg[0];
if (app_mode_we) begin
app_mode_reg <= 1'h1;
app_mode_reg <= app_mode_new;
end
if (led_we) begin
@ -484,12 +486,27 @@ module tk1 #(
end
end
//----------------------------------------------------------------
// app_mode_ctrl
//
// Automatically lower privilege when executing above ROM.
// ----------------------------------------------------------------
always @* begin : app_mode_ctrl
app_mode_new = 1'h0;
app_mode_we = 1'h0;
if (cpu_valid & cpu_instr) begin
if (cpu_addr > FW_ROM_LAST) begin
app_mode_new = 1'h1;
app_mode_we = 1'h1;
end
end
end
//----------------------------------------------------------------
// api
//----------------------------------------------------------------
always @* begin : api
app_mode_we = 1'h0;
led_we = 1'h0;
gpio3_we = 1'h0;
gpio4_we = 1'h0;
@ -516,10 +533,6 @@ module tk1 #(
if (cs) begin
tmp_ready = 1'h1;
if (we) begin
if (address == ADDR_APP_MODE_CTRL) begin
app_mode_we = 1'h1;
end
if (address == ADDR_LED) begin
led_we = 1'h1;
end