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/*
* Copyright © 2014 Broadcom
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "vc4_qpu.h"
static bool
writes_reg(uint64_t inst, uint32_t w)
{
return (QPU_GET_FIELD(inst, QPU_WADDR_ADD) == w ||
QPU_GET_FIELD(inst, QPU_WADDR_MUL) == w);
}
static bool
_reads_reg(uint64_t inst, uint32_t r, bool ignore_a, bool ignore_b)
{
struct {
uint32_t mux, addr;
} src_regs[] = {
{ QPU_GET_FIELD(inst, QPU_ADD_A) },
{ QPU_GET_FIELD(inst, QPU_ADD_B) },
{ QPU_GET_FIELD(inst, QPU_MUL_A) },
{ QPU_GET_FIELD(inst, QPU_MUL_B) },
};
for (int i = 0; i < ARRAY_SIZE(src_regs); i++) {
if (!ignore_a &&
src_regs[i].mux == QPU_MUX_A &&
(QPU_GET_FIELD(inst, QPU_RADDR_A) == r))
return true;
if (!ignore_b &&
QPU_GET_FIELD(inst, QPU_SIG) != QPU_SIG_SMALL_IMM &&
src_regs[i].mux == QPU_MUX_B &&
(QPU_GET_FIELD(inst, QPU_RADDR_B) == r))
return true;
}
return false;
}
static bool
reads_reg(uint64_t inst, uint32_t r)
{
return _reads_reg(inst, r, false, false);
}
static bool
reads_a_reg(uint64_t inst, uint32_t r)
{
return _reads_reg(inst, r, false, true);
}
static bool
reads_b_reg(uint64_t inst, uint32_t r)
{
return _reads_reg(inst, r, true, false);
}
static bool
writes_sfu(uint64_t inst)
{
return (writes_reg(inst, QPU_W_SFU_RECIP) ||
writes_reg(inst, QPU_W_SFU_RECIPSQRT) ||
writes_reg(inst, QPU_W_SFU_EXP) ||
writes_reg(inst, QPU_W_SFU_LOG));
}
/**
* Checks for the instruction restrictions from page 37 ("Summary of
* Instruction Restrictions").
*/
void
vc4_qpu_validate(uint64_t *insts, uint32_t num_inst)
{
bool scoreboard_locked = false;
for (int i = 0; i < num_inst; i++) {
uint64_t inst = insts[i];
if (QPU_GET_FIELD(inst, QPU_SIG) != QPU_SIG_PROG_END) {
if (qpu_inst_is_tlb(inst))
scoreboard_locked = true;
continue;
}
/* "The Thread End instruction must not write to either physical
* regfile A or B."
*/
assert(QPU_GET_FIELD(inst, QPU_WADDR_ADD) >= 32);
assert(QPU_GET_FIELD(inst, QPU_WADDR_MUL) >= 32);
/* Can't trigger an implicit wait on scoreboard in the program
* end instruction.
*/
assert(!qpu_inst_is_tlb(inst) || scoreboard_locked);
/* Two delay slots will be executed. */
assert(i + 2 <= num_inst);
for (int j = i; j < i + 2; j++) {
/* "The last three instructions of any program
* (Thread End plus the following two delay-slot
* instructions) must not do varyings read, uniforms
* read or any kind of VPM, VDR, or VDW read or
* write."
*/
assert(!writes_reg(insts[j], QPU_W_VPM));
assert(!reads_reg(insts[j], QPU_R_VARY));
assert(!reads_reg(insts[j], QPU_R_UNIF));
assert(!reads_reg(insts[j], QPU_R_VPM));
/* "The Thread End instruction and the following two
* delay slot instructions must not write or read
* address 14 in either regfile A or B."
*/
assert(!writes_reg(insts[j], 14));
assert(!reads_reg(insts[j], 14));
}
/* "The final program instruction (the second delay slot
* instruction) must not do a TLB Z write."
*/
assert(!writes_reg(insts[i + 2], QPU_W_TLB_Z));
}
/* "A scoreboard wait must not occur in the first two instructions of
* a fragment shader. This is either the explicit Wait for Scoreboard
* signal or an implicit wait with the first tile-buffer read or
* write instruction."
*/
for (int i = 0; i < 2; i++) {
uint64_t inst = insts[i];
assert(!qpu_inst_is_tlb(inst));
}
/* "If TMU_NOSWAP is written, the write must be three instructions
* before the first TMU write instruction. For example, if
* TMU_NOSWAP is written in the first shader instruction, the first
* TMU write cannot occur before the 4th shader instruction."
*/
int last_tmu_noswap = -10;
for (int i = 0; i < num_inst; i++) {
uint64_t inst = insts[i];
assert((i - last_tmu_noswap) > 3 ||
(!writes_reg(inst, QPU_W_TMU0_S) &&
!writes_reg(inst, QPU_W_TMU1_S)));
if (writes_reg(inst, QPU_W_TMU_NOSWAP))
last_tmu_noswap = i;
}
/* "An instruction must not read from a location in physical regfile A
* or B that was written to by the previous instruction."
*/
for (int i = 0; i < num_inst - 1; i++) {
uint64_t inst = insts[i];
uint32_t add_waddr = QPU_GET_FIELD(inst, QPU_WADDR_ADD);
uint32_t mul_waddr = QPU_GET_FIELD(inst, QPU_WADDR_MUL);
uint32_t waddr_a, waddr_b;
if (inst & QPU_WS) {
waddr_b = add_waddr;
waddr_a = mul_waddr;
} else {
waddr_a = add_waddr;
waddr_b = mul_waddr;
}
assert(waddr_a >= 32 || !reads_a_reg(insts[i + 1], waddr_a));
assert(waddr_b >= 32 || !reads_b_reg(insts[i + 1], waddr_b));
}
/* "After an SFU lookup instruction, accumulator r4 must not be read
* in the following two instructions. Any other instruction that
* results in r4 being written (that is, TMU read, TLB read, SFU
* lookup) cannot occur in the two instructions following an SFU
* lookup."
*/
int last_sfu_inst = -10;
for (int i = 0; i < num_inst - 1; i++) {
uint64_t inst = insts[i];
uint32_t sig = QPU_GET_FIELD(inst, QPU_SIG);
assert(i - last_sfu_inst > 2 ||
(!writes_sfu(inst) &&
sig != QPU_SIG_LOAD_TMU0 &&
sig != QPU_SIG_LOAD_TMU1 &&
sig != QPU_SIG_COLOR_LOAD));
if (writes_sfu(inst))
last_sfu_inst = i;
}
int last_r5_write = -10;
for (int i = 0; i < num_inst - 1; i++) {
uint64_t inst = insts[i];
/* "An instruction that does a vector rotate by r5 must not
* immediately follow an instruction that writes to r5."
*/
assert(last_r5_write != i - 1 ||
QPU_GET_FIELD(inst, QPU_SIG) != QPU_SIG_SMALL_IMM ||
QPU_GET_FIELD(inst, QPU_SMALL_IMM) != 48);
}
/* "An instruction that does a vector rotate must not immediately
* follow an instruction that writes to the accumulator that is being
* rotated.
*
* XXX: TODO.
*/
/* "After an instruction that does a TLB Z write, the multisample mask
* must not be read as an instruction input argument in the following
* two instruction. The TLB Z write instruction can, however, be
* followed immediately by a TLB color write."
*/
for (int i = 0; i < num_inst - 1; i++) {
uint64_t inst = insts[i];
if (writes_reg(inst, QPU_W_TLB_Z)) {
assert(!reads_a_reg(insts[i + 1], QPU_R_MS_REV_FLAGS));
assert(!reads_a_reg(insts[i + 2], QPU_R_MS_REV_FLAGS));
}
}
/*
* "A single instruction can only perform a maximum of one of the
* following closely coupled peripheral accesses in a single
* instruction: TMU write, TMU read, TLB write, TLB read, TLB
* combined color read and write, SFU write, Mutex read or Semaphore
* access."
*/
for (int i = 0; i < num_inst - 1; i++) {
uint64_t inst = insts[i];
assert(qpu_num_sf_accesses(inst) <= 1);
}
}
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