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probe: IPC3 firmware probe fixes and direct host-ring extraction for i.MX8MP #11399

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probe: IPC3 firmware probe fixes and direct host-ring extraction for i.MX8MP #11399

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f8a9041
audio/sof/probe: fix IPC3 probe point buffer lookup
Nov 2, 2026
c955e4c
audio/sof/probe: zero-initialize DMA config structs
Nov 2, 2026
a638664
audio/sof/probe: IPC3+Zephyr: direct-write extraction to host ring
Nov 2, 2026
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2 changes: 2 additions & 0 deletions app/boards/imx8mp_evk_mimx8ml8_adsp.conf
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,8 @@ CONFIG_DMA=y
CONFIG_DMA_NXP_SDMA=y
CONFIG_DAI_NXP_MICFIL=y
CONFIG_TRACE=n
CONFIG_PROBE=y
CONFIG_PROBE_POINTS_MAX=16
CONFIG_SHARED_INTERRUPTS=y
CONFIG_ZEPHYR_NATIVE_DRIVERS=y
CONFIG_SAI_HAS_MCLK_CONFIG_OPTION=y
Expand Down
87 changes: 82 additions & 5 deletions src/probe/probe.c
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Expand Up @@ -51,8 +51,17 @@ LOG_MODULE_REGISTER(probe, CONFIG_SOF_LOG_LEVEL);
#define PROBE_POINT_INVALID 0xFFFFFFFF

#define PROBE_BUFFER_LOCAL_SIZE 8192
/* host buffer layout: u32 write counter in the first bytes, ring data after the header */
#define PROBE_HOST_HDR_SIZE 4096
#define DMA_ELEM_SIZE 32

@dbaluta dbaluta Nov 10, 2026

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In the zephyr/drivers/dma have a look at dma_nxp_sof_host_dma.c. This should provide you a way to "DMA" data into RAM seen by Linux.

/* i.MX IPC3: the DSP writes extraction data straight into the host ring */
#if CONFIG_IPC_MAJOR_3 && CONFIG_ZEPHYR_NATIVE_DRIVERS && CONFIG_IMX
#define PROBE_HOST_RING 1
#else
#define PROBE_HOST_RING 0
#endif

/**
* DMA buffer
*/
Expand All @@ -74,6 +83,11 @@ struct probe_dma_ext {
struct dma_sg_config config; /**< DMA SG config */
struct probe_dma_buf dmapb; /**< DMA buffer pointer */
struct dma_copy dc; /**< DMA copy */
#if PROBE_HOST_RING
uintptr_t host_base; /**< host buffer: header + ring (IPC3) */
uint32_t host_size; /**< host ring size in bytes (IPC3) */
uint32_t host_wr; /**< total bytes written to host ring (IPC3) */
#endif
};

/**
Expand Down Expand Up @@ -195,13 +209,18 @@ __cold static int probe_dma_init(struct probe_dma_ext *dma, uint32_t direction)
{

@dbaluta dbaluta Nov 10, 2026

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Use probe: prefix. We usually dont use path names in the subject prefix like audio/sof/probe. See git log --oneline src/probe/probe.c.

uint32_t addr_align;
uint32_t channel;
struct dma_config dma_cfg;
struct dma_block_config dma_block_cfg;
struct dma_config dma_cfg = {0};
struct dma_block_config dma_block_cfg = {0};
int err = 0;

assert_can_be_cold();

#if CONFIG_IPC_MAJOR_3
/* IPC3: stream_tag carries the host buffer address; use host DMA channel 0 */
channel = 0;
#else
channel = ((union ipc4_connector_node_id)dma->stream_tag).f.v_index;
#endif

/* request DMA in the dir LMEM->HMEM with shared access */
dma->dc.dmac = sof_dma_get(direction, 0, SOF_DMA_DEV_HOST,
Expand Down Expand Up @@ -259,6 +278,10 @@ __cold static int probe_dma_init(struct probe_dma_ext *dma, uint32_t direction)
case SOF_DMA_DIR_LMEM_TO_HMEM:
dma_cfg.channel_direction = MEMORY_TO_HOST;
dma_block_cfg.source_address = (uint32_t)dma->dmapb.addr;
#if PROBE_HOST_RING
/* never transferred, probe_host_write() copies; driver wants non-zero */
dma_block_cfg.dest_address = (uint32_t)dma->dmapb.addr;
#endif
break;
case SOF_DMA_DIR_HMEM_TO_LMEM:
dma_cfg.channel_direction = HOST_TO_MEMORY;
Expand Down Expand Up @@ -320,6 +343,42 @@ __cold static int probe_dma_deinit(struct probe_dma_ext *dma)
return 0;
}

#if PROBE_HOST_RING
/*
* Copy extraction data straight into the host ring and publish the new
* write counter. The i.MX host DMA driver can only memcpy inside DSP
* memory, so the DSP writes to the host buffer itself and flushes its
* data cache.
*/
static int probe_host_write(struct probe_dma_ext *dma, const void *src, uint32_t bytes)
{
uint8_t *ring = (uint8_t *)dma->host_base + PROBE_HOST_HDR_SIZE;
uint32_t off, head;

if (!dma->host_base || !dma->host_size)
return -EINVAL;

off = dma->host_wr % dma->host_size;
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head = MIN(bytes, dma->host_size - off);

memcpy(ring + off, src, head);
dcache_writeback_region((__sparse_force void __sparse_cache *)(ring + off), head);
if (bytes > head) {
memcpy(ring, (const uint8_t *)src + head, bytes - head);
dcache_writeback_region((__sparse_force void __sparse_cache *)ring,
bytes - head);
}

/* host_wr wraps at 2^32; kernel side casts its counter to u32 before subtracting */
dma->host_wr += bytes;
*(volatile uint32_t *)dma->host_base = dma->host_wr;
dcache_writeback_region((__sparse_force void __sparse_cache *)dma->host_base,
sizeof(uint32_t));

return 0;
}
#endif

/*
* \brief Probe task for extraction.
*
Expand Down Expand Up @@ -351,7 +410,10 @@ static enum task_state probe_task(void *data)
avail = _probe->ext_dma.dmapb.end_addr - _probe->ext_dma.dmapb.r_ptr;

if (avail > 0)
#if CONFIG_ZEPHYR_NATIVE_DRIVERS
#if PROBE_HOST_RING
err = probe_host_write(&_probe->ext_dma,
(void *)_probe->ext_dma.dmapb.r_ptr, avail);
#elif CONFIG_ZEPHYR_NATIVE_DRIVERS
err = dma_reload(_probe->ext_dma.dc.dmac->z_dev,
_probe->ext_dma.dc.chan->index, 0, 0, avail);
#else
Expand Down Expand Up @@ -417,6 +479,15 @@ __cold int probe_init(const struct probe_dma *probe_dma)
return -EINVAL;
}

#if PROBE_HOST_RING
/* ring must hold a full local buffer and wrap cleanly at 2^32 */
if (probe_dma && (probe_dma->dma_buffer_size < PROBE_BUFFER_LOCAL_SIZE ||
(probe_dma->dma_buffer_size & (probe_dma->dma_buffer_size - 1)))) {
tr_err(&pr_tr, "bad host ring size %u", probe_dma->dma_buffer_size);
return -EINVAL;
}
#endif

/* alloc probes main struct */
sof_get()->probe = rzalloc(SOF_MEM_FLAG_USER,
sizeof(*_probe));
Expand Down Expand Up @@ -446,6 +517,12 @@ __cold int probe_init(const struct probe_dma *probe_dma)

_probe->ext_dma.stream_tag = probe_dma->stream_tag;
_probe->ext_dma.dma_buffer_size = probe_dma->dma_buffer_size;
#if PROBE_HOST_RING
/* i.MX: stream_tag holds the physical address of the host ring buffer */
_probe->ext_dma.host_base = probe_dma->stream_tag;
_probe->ext_dma.host_size = probe_dma->dma_buffer_size;
_probe->ext_dma.host_wr = 0;
#endif

err = probe_dma_init(&_probe->ext_dma, SOF_DMA_DIR_LMEM_TO_HMEM);
if (err < 0) {
Expand Down Expand Up @@ -1249,7 +1326,7 @@ __cold int probe_point_add(uint32_t count, const struct probe_point *probe)
#elif CONFIG_AMD_ACP_HOST_DMA_PROBE
dev = ipc_get_buffer_by_id(ipc_get(), buf_id->full_id);
#else
dev = ipc_get_comp_by_id(ipc_get(), buf_id->full_id);
dev = ipc_get_comp_dev(ipc_get(), COMP_TYPE_ANY, buf_id->full_id);
#endif
/* check if buffer exists */
if (!dev) {
Expand Down Expand Up @@ -1512,7 +1589,7 @@ __cold int probe_point_remove(uint32_t count, const uint32_t *buffer_id)
#if CONFIG_AMD_ACP_HOST_DMA_PROBE
dev = ipc_get_buffer_by_id(ipc_get(), buffer_id[i]);
#else
dev = ipc_get_comp_by_id(ipc_get(), buffer_id[i]);
dev = ipc_get_comp_dev(ipc_get(), COMP_TYPE_ANY, buffer_id[i]);
#endif
if (dev) {
struct comp_buffer *probe_buf =
Expand Down
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