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fpga: Add stateful access control

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Add access stateful control register that toggles if access to a
      resources is granted based on if code is excuted from ROM or RAM.
      The register is used to enable or block access to SPI but
      potentially other HW resources.

Signed-off-by: Joachim Strömbergson <joachim@assured.se>
This commit is contained in:
Joachim Strömbergson 2024-07-09 12:58:45 +02:00 • committed by Daniel Jobson
parent 7b4a659868
commit c0a79e77c6
No known key found for this signature in database
GPG key ID: 3707A9DBF4BB8F1A
2 changed files with 35 additions and 15 deletions
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47
hw/application_fpga/core/tk1/rtl/tk1.v
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@ -26,6 +26,9 @@ module tk1(
output wire force_trap,
output system_reset,
input wire ram_access,
input wire rom_access,
output wire [14 : 0] ram_addr_rand,
output wire [31 : 0] ram_data_rand,
@ -164,7 +167,9 @@ module tk1(
reg force_trap_reg;
reg force_trap_set;
reg spi_access_ok;
reg access_ok_reg;
reg access_ok_new;
reg access_ok_we;
//----------------------------------------------------------------
@ -240,13 +245,13 @@ module tk1(
.spi_mosi(spi_mosi),
.spi_miso(spi_miso),
.spi_enable((spi_enable & spi_access_ok)),
.spi_enable_vld((spi_enable_vld & spi_access_ok)),
.spi_start((spi_start & spi_access_ok)),
.spi_enable((spi_enable & spi_access_ok_reg)),
.spi_enable_vld((spi_enable_vld & spi_access_ok_reg)),
.spi_start((spi_start & spi_access_ok_reg)),
.spi_tx_data(spi_tx_data),
.spi_tx_data_vld((spi_tx_data_vld & spi_access_ok)),
.spi_tx_data_vld((spi_tx_data_vld & spi_access_ok_reg)),
.spi_rx_data(spi_rx_data),
.spi_ready((spi_ready & spi_access_ok))
.spi_ready((spi_ready & spi_access_ok_reg))
);
`endif // INCLUDE_SPI_MASTER
@ -282,13 +287,14 @@ module tk1(
cdi_mem[7] <= 32'h0;
cpu_trap_ctr_reg <= 24'h0;
cpu_trap_led_reg <= 3'h0;
cpu_mon_en_reg <= 1'h0;
cpu_mon_en_reg <= 1'h0;
cpu_mon_first_reg <= 32'h0;
cpu_mon_last_reg <= 32'h0;
ram_addr_rand_reg <= 15'h0;
ram_addr_rand_reg <= 15'h0;
ram_data_rand_reg <= 32'h0;
force_trap_reg <= 1'h0;
system_reset_reg <= 1'h0;
access_ok_reg <= 1'h0;
end
else begin
@ -361,6 +367,10 @@ module tk1(
if (force_trap_set) begin
force_trap_reg <= 1'h1;
end
if (access_ok_we) begin
access_ok_reg <= access_ok_new;
end
end
end // reg_update
@ -389,17 +399,24 @@ module tk1(
//----------------------------------------------------------------
// spi_access_control
// access_control
//
// Logic thar controls if any access to the SPI master is done
// by FW-code.
// Logic that controls access to resources that only FW (ROM),
// not applications should be allowed to use.
//----------------------------------------------------------------
always @*
begin : spi_access_control
spi_access_ok = 1'h0;
begin : access_control
access_ok_new = 1'h0;
access_ok_we = 1'h0;
if (cpu_addr[31 : 30] == ROM_PREFIX) begin
spi_access_ok = 1'h1;
if (rom_access) begin
access_ok_new = 1'h1;
access_ok_we = 1'h1;
end
if (ram_access) begin
access_ok_new = 1'h0;
access_ok_we = 1'h1;
end
end