rtl/gfx/firmware: implement bootloader

2 files changed, 179 insertions, 0 deletions

diff --git a/rtl/gfx/firmware/custom_ops.S b/rtl/gfx/firmware/custom_ops.S
new file mode 100644
index 0000000..95a2f53
--- /dev/null
+++ b/rtl/gfx/firmware/custom_ops.S
@@ -0,0 +1,103 @@
+// This is free and unencumbered software released into the public domain.
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+
+#define regnum_q0   0
+#define regnum_q1   1
+#define regnum_q2   2
+#define regnum_q3   3
+
+#define regnum_x0   0
+#define regnum_x1   1
+#define regnum_x2   2
+#define regnum_x3   3
+#define regnum_x4   4
+#define regnum_x5   5
+#define regnum_x6   6
+#define regnum_x7   7
+#define regnum_x8   8
+#define regnum_x9   9
+#define regnum_x10 10
+#define regnum_x11 11
+#define regnum_x12 12
+#define regnum_x13 13
+#define regnum_x14 14
+#define regnum_x15 15
+#define regnum_x16 16
+#define regnum_x17 17
+#define regnum_x18 18
+#define regnum_x19 19
+#define regnum_x20 20
+#define regnum_x21 21
+#define regnum_x22 22
+#define regnum_x23 23
+#define regnum_x24 24
+#define regnum_x25 25
+#define regnum_x26 26
+#define regnum_x27 27
+#define regnum_x28 28
+#define regnum_x29 29
+#define regnum_x30 30
+#define regnum_x31 31
+
+#define regnum_zero 0
+#define regnum_ra   1
+#define regnum_sp   2
+#define regnum_gp   3
+#define regnum_tp   4
+#define regnum_t0   5
+#define regnum_t1   6
+#define regnum_t2   7
+#define regnum_s0   8
+#define regnum_s1   9
+#define regnum_a0  10
+#define regnum_a1  11
+#define regnum_a2  12
+#define regnum_a3  13
+#define regnum_a4  14
+#define regnum_a5  15
+#define regnum_a6  16
+#define regnum_a7  17
+#define regnum_s2  18
+#define regnum_s3  19
+#define regnum_s4  20
+#define regnum_s5  21
+#define regnum_s6  22
+#define regnum_s7  23
+#define regnum_s8  24
+#define regnum_s9  25
+#define regnum_s10 26
+#define regnum_s11 27
+#define regnum_t3  28
+#define regnum_t4  29
+#define regnum_t5  30
+#define regnum_t6  31
+
+// x8 is s0 and also fp
+#define regnum_fp   8
+
+#define r_type_insn(_f7, _rs2, _rs1, _f3, _rd, _opc) \
+.word (((_f7) << 25) | ((_rs2) << 20) | ((_rs1) << 15) | ((_f3) << 12) | ((_rd) << 7) | ((_opc) << 0))
+
+#define picorv32_getq_insn(_rd, _qs) \
+r_type_insn(0b0000000, 0, regnum_ ## _qs, 0b100, regnum_ ## _rd, 0b0001011)
+
+#define picorv32_setq_insn(_qd, _rs) \
+r_type_insn(0b0000001, 0, regnum_ ## _rs, 0b010, regnum_ ## _qd, 0b0001011)
+
+#define picorv32_retirq_insn() \
+r_type_insn(0b0000010, 0, 0, 0b000, 0, 0b0001011)
+
+#define picorv32_maskirq_insn(_rd, _rs) \
+r_type_insn(0b0000011, 0, regnum_ ## _rs, 0b110, regnum_ ## _rd, 0b0001011)
+
+#define picorv32_waitirq_insn(_rd) \
+r_type_insn(0b0000100, 0, 0, 0b100, regnum_ ## _rd, 0b0001011)
+
+#define picorv32_timer_insn(_rd, _rs) \
+r_type_insn(0b0000101, 0, regnum_ ## _rs, 0b110, regnum_ ## _rd, 0b0001011)
+
+
diff --git a/rtl/gfx/firmware/gfx_bootrom.S b/rtl/gfx/firmware/gfx_bootrom.S
new file mode 100644
index 0000000..bf7bd7d
--- /dev/null
+++ b/rtl/gfx/firmware/gfx_bootrom.S
@@ -0,0 +1,76 @@
+#include "custom_ops.S"
+
+.text
+
+.global _start
+_start:
+
+	li   a0, 0x00300000       # HOST_CTRL_BASE
+	li   a1, 1 << 1 | 1 << 0  # ARINT | AWINT
+	li   a2, 1 << 0           # B.VALID = 1
+	li   a3, 0x8              # Firmware handover word
+	la   a4, .read_data
+	li   a5, 1 << 11 | 1 << 9 # CTRL.WVALID | CTRL.AWVALID
+	li   a6, 1 << 12          # CTRL.BDONE, doesn't fit in andi
+
+	sw   a1, 0(a0)
+
+.wait_axi:
+	picorv32_waitirq_insn(zero)
+
+	lw   t0, 0(a0)
+	andi t1, t0, 1 << 8 # ARVALID
+	bne  t1, zero, .read
+	and  t0, t0, a5
+	beq  t0, a5, .write
+	j    .wait_axi
+
+.read:
+	lw   t0, 4(a0)
+	andi t1, t0, 1 << 0 # AW.VALID
+	beq  t1, zero, .wait_axi
+	andi t0, t0, 0b11 << 2
+	add  t0, a4, t0
+	lw   t0, 0(t0)
+	sw   t0, 12(a0) # R.DATA
+
+.read_done:
+	lw   t0, 0(a0)
+	andi t0, t0, 1 << 10 # CTRL.RDONE
+	beq  t0, zero, .read_done
+	j    .wait_axi
+
+.write:
+	lw   t0, 8(a0)
+	andi t1, t0, 1 << 0 # AW.VALID
+	beq  t1, zero, .wait_axi
+	lw   t1, 16(a0)
+	sw   a2, 20(a0)
+
+.write_done:
+	lw   t2, 0(a0)
+	and  t2, t2, a6
+	beq  t2, zero, .write_done
+
+	andi t0, t0, ~0b11
+	bne  t0, a3, .wait_axi
+	sw   zero, 0(a0)
+	# Pass magic & hardware version
+	lw   a0, 0(a4)
+	lw   a1, 4(a4)
+	jalr t1
+	j    .
+
+.balign 4
+
+.read_data:
+	# Magic
+	.word 0x4a7a7b0c
+	# Hardware major.minor.patch
+	.word 1 << 16 | 0 << 8 | 0 << 0
+	# Firmware yyyy.mm.dd.build
+	.word 2024 << 18 | 5 << 15 | 12 << 10 | 1 << 0
+	# Register map version, rev 0 means this is the bootrom firmware
+	.word 0
+
+.balign 4