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fpga: Add new SPI access control logis

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New logic looks at instruction execution from a defined
      trampoline address to enable stateful SPI access.

      The access is disabled as soon as an instruction is executed
      from any address in RAM.

Signed-off-by: Joachim Strömbergson <joachim@assured.se>
This commit is contained in:
Joachim Strömbergson 2024-07-11 11:04:07 +02:00
parent bc9fcb7258
commit 7e26c742bf
No known key found for this signature in database
GPG Key ID: 865B8A548EA61679
2 changed files with 108 additions and 56 deletions
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111
hw/application_fpga/core/tk1/rtl/tk1.v
View File

@ -25,9 +25,6 @@ module tk1(
input wire cpu_valid,
output wire force_trap,
input wire ram_access,
input wire rom_access,
output wire [14 : 0] ram_aslr,
output wire [31 : 0] ram_scramble,
@ -100,10 +97,9 @@ module tk1(
localparam ADDR_SPI_EN = 8'h80;
localparam ADDR_SPI_XFER = 8'h81;
localparam ADDR_SPI_DATA = 8'h82;
localparam ADDR_SPI_CMD = 8'h83;
`endif // INCLUDE_SPI_MASTER
localparam ADDR_ACCESS_CTRL = 8'h83;
localparam TK1_NAME0 = 32'h746B3120; // "tk1 "
localparam TK1_NAME1 = 32'h6d6b6466; // "mkdf"
localparam TK1_VERSION = 32'h00000005;
@ -111,6 +107,10 @@ module tk1(
localparam FW_RAM_FIRST = 32'hd0000000;
localparam FW_RAM_LAST = 32'hd00007ff;
`ifdef INCLUDE_SPI_MASTER
localparam RAM_PREFIX = 2'h1;
`endif // INCLUDE_SPI_MASTER
//----------------------------------------------------------------
// Registers including update variables and write enable.
@ -161,8 +161,14 @@ module tk1(
reg force_trap_reg;
reg force_trap_set;
reg access_ok_reg;
reg access_ok_we;
`ifdef INCLUDE_SPI_MASTER
reg [31 : 0] spi_cmd_addr_reg;
reg spi_cmd_addr_we;
reg spi_access_ctrl_reg;
reg spi_access_ctrl_new;
reg spi_access_ctrl_we;
`endif // INCLUDE_SPI_MASTER
//----------------------------------------------------------------
@ -236,11 +242,11 @@ module tk1(
.spi_mosi(spi_mosi),
.spi_miso(spi_miso),
.spi_enable((spi_enable & access_ok_reg)),
.spi_enable_vld((spi_enable_vld & access_ok_reg)),
.spi_start((spi_start & access_ok_reg)),
.spi_enable(spi_enable),
.spi_enable_vld(spi_enable_vld),
.spi_start(spi_start),
.spi_tx_data(spi_tx_data),
.spi_tx_data_vld((spi_tx_data_vld & access_ok_reg)),
.spi_tx_data_vld(spi_tx_data_vld),
.spi_rx_data(spi_rx_data),
.spi_ready(spi_ready)
);
@ -284,7 +290,11 @@ module tk1(
ram_aslr_reg <= 15'h0;
ram_scramble_reg <= 32'h0;
force_trap_reg <= 1'h0;
access_ok_reg <= 1'h0;
`ifdef INCLUDE_SPI_MASTER
spi_cmd_addr_reg <= 32'h0;
spi_access_ctrl_reg <= 1'h0;
`endif // INCLUDE_SPI_MASTER
end
else begin
@ -356,9 +366,16 @@ module tk1(
force_trap_reg <= 1'h1;
end
if (access_ok_we) begin
access_ok_reg <= write_data[0];
`ifdef INCLUDE_SPI_MASTER
if (spi_cmd_addr_we) begin
spi_cmd_addr_reg <= write_data;
end
if (spi_access_ctrl_we) begin
spi_access_ctrl_reg <= spi_access_ctrl_new;
end
`endif // INCLUDE_SPI_MASTER
end
end // reg_update
@ -405,7 +422,7 @@ module tk1(
force_trap_set = 1'h0;
if (cpu_valid) begin
if (cpu_addr[31 : 30] == 2'h01 & |cpu_addr[29 : 17]) begin
if (cpu_addr[31 : 30] == 2'h1 & |cpu_addr[29 : 17]) begin
force_trap_set = 1'h1;
end
@ -426,6 +443,39 @@ module tk1(
end
`ifdef INCLUDE_SPI_MASTER
//----------------------------------------------------------------
// spi_access_ctrl
//
// Logic that implements the detection of a SPI command trampoline
// event, when the CPU reads an instruction from the specified
// SPI command handler FW entry point. When that happens SPI
// access is enabled.
//
// The logic also handles the event when the SPI access control
// API is written to. WHen that happens SPI access is
// disabled.
//----------------------------------------------------------------
always @*
begin : spi_access_ctrl
spi_access_ctrl_new = 1'h0;
spi_access_ctrl_we = 1'h0;
if (cpu_valid & cpu_instr) begin
if (cpu_addr == spi_cmd_addr_reg) begin
spi_access_ctrl_new = 1'h1;
spi_access_ctrl_we = 1'h1;
end
if (cpu_addr[31 : 30] == RAM_PREFIX) begin
spi_access_ctrl_new = 1'h0;
spi_access_ctrl_we = 1'h1;
end
end
end
`endif // INCLUDE_SPI_MASTER
//----------------------------------------------------------------
// api
//----------------------------------------------------------------
@ -448,15 +498,15 @@ module tk1(
cpu_mon_en_we = 1'h0;
tmp_read_data = 32'h0;
tmp_ready = 1'h0;
access_ok_we = 1'h0;
`ifdef INCLUDE_SPI_MASTER
spi_cmd_addr_we = 1'h0;
spi_enable_vld = 1'h0;
spi_start = 1'h0;
spi_tx_data_vld = 1'h0;
spi_enable = write_data[0] & access_ok_reg;
spi_tx_data = write_data[7 : 0] & {8{access_ok_reg}};
spi_enable = write_data[0] & spi_access_ctrl_reg;
spi_tx_data = write_data[7 : 0] & {8{spi_access_ctrl_reg}};
`endif // INCLUDE_SPI_MASTER
@ -528,22 +578,23 @@ module tk1(
end
end
if (address == ADDR_ACCESS_CTRL) begin
access_ok_we = 1'h1;
end
`ifdef INCLUDE_SPI_MASTER
if (address == ADDR_SPI_EN) begin
spi_enable_vld = 1'h1;
spi_enable_vld = spi_access_ctrl_reg;
end
if (address == ADDR_SPI_XFER) begin
spi_start = 1'h1;
spi_start = spi_access_ctrl_reg;
end
if (address == ADDR_SPI_DATA) begin
spi_tx_data_vld = 1'h1;
spi_tx_data_vld = spi_access_ctrl_reg;
end
if (address == ADDR_SPI_CMD) begin
if (!switch_app_reg) begin
spi_cmd_addr_we = 1'h1;
end
end
`endif // INCLUDE_SPI_MASTER
@ -598,16 +649,20 @@ module tk1(
`ifdef INCLUDE_SPI_MASTER
if (address == ADDR_SPI_XFER) begin
if (access_ok_reg) begin
if (spi_access_ctrl_reg) begin
tmp_read_data[0] = spi_ready;
end
end
if (address == ADDR_SPI_DATA) begin
if (access_ok_reg) begin
if (spi_access_ctrl_reg) begin
tmp_read_data[7 : 0] = spi_rx_data;
end
end
if (address == ADDR_SPI_CMD) begin
tmp_read_data = spi_cmd_addr_reg;
end
`endif // INCLUDE_SPI_MASTER
end

3
hw/application_fpga/rtl/application_fpga.v
View File

@ -321,9 +321,6 @@ module application_fpga(
.cpu_trap(cpu_trap),
.force_trap(force_trap),
.ram_access(ram_cs),
.rom_access(rom_cs),
.ram_aslr(ram_aslr),
.ram_scramble(ram_scramble),