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hw/dma/xlnx_csu_dma: don't throw guest errors when stopping the SRC DMA

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UG1087 states for the source channel that: if SIZE is programmed to 0, and the
DMA is started, the interrupts DONE and MEM_DONE will be asserted.

This implies that it is allowed for the guest to stop the source DMA by writing
a size of 0 to the SIZE register, so remove the LOG_GUEST_ERROR in that case.

While at it remove the comment marking the SIZE register as write-only.

See: https://docs.xilinx.com/r/en-US/ug1087-zynq-ultrascale-registers/CSUDMA_SRC_SIZE-CSUDMA-Register

Signed-off-by: Frederic Konrad <fkonrad@amd.com>
Reviewed-by: Francisco Iglesias <francisco.iglesias@amd.com>
Message-id: 20231124143505.1493184-4-fkonrad@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Frederic Konrad 2023-11-24 14:35:05 +00:00 committed by Peter Maydell
parent a9bc470ec2
commit 1ee80592bf
1 changed files with 8 additions and 4 deletions
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12
hw/dma/xlnx_csu_dma.c
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@ -39,7 +39,7 @@
REG32(ADDR, 0x0)
FIELD(ADDR, ADDR, 2, 30) /* wo */
REG32(SIZE, 0x4)
FIELD(SIZE, SIZE, 2, 27) /* wo */
FIELD(SIZE, SIZE, 2, 27)
FIELD(SIZE, LAST_WORD, 0, 1) /* rw, only exists in SRC */
REG32(STATUS, 0x8)
FIELD(STATUS, DONE_CNT, 13, 3) /* wtc */
@ -335,10 +335,14 @@ static uint64_t addr_pre_write(RegisterInfo *reg, uint64_t val)
static uint64_t size_pre_write(RegisterInfo *reg, uint64_t val)
{
XlnxCSUDMA *s = XLNX_CSU_DMA(reg->opaque);
uint64_t size = val & R_SIZE_SIZE_MASK;
if (s->regs[R_SIZE] != 0) {
qemu_log_mask(LOG_GUEST_ERROR,
"%s: Starting DMA while already running.\n", __func__);
if (size || s->is_dst) {
qemu_log_mask(LOG_GUEST_ERROR,
"%s: Starting DMA while already running.\n",
__func__);
}
}
if (!s->is_dst) {
@ -346,7 +350,7 @@ static uint64_t size_pre_write(RegisterInfo *reg, uint64_t val)
}
/* Size is word aligned */
return val & R_SIZE_SIZE_MASK;
return size;
}
static uint64_t size_post_read(RegisterInfo *reg, uint64_t val)