* [PATCH] net: airoha: npu: use coherent DMA for mailbox messages
@ 2026-08-05 7:08 Daniel Pawlik
2026-08-05 9:59 ` Lorenzo Bianconi
2026-08-06 7:26 ` [PATCH v2] " Daniel Pawlik
0 siblings, 2 replies; 5+ messages in thread
From: Daniel Pawlik @ 2026-08-05 7:08 UTC (permalink / raw)
To: netdev; +Cc: lorenzo, win847, linux-arm-kernel, linux-mediatek, Daniel Pawlik
Commit 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox
buffer") switched airoha_npu_send_msg() to DMA_BIDIRECTIONAL so
non-coherent CPUs invalidate caches before reading NPU GET responses.
On EN7581 + MT7996 that change regresses probe: the mailbox completes
successfully, but WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0 and
mt76 never binds NPU offload. Healthy boards report 0.1111.
Mailbox messages are tiny and already copied by the caller. Bounce
through dma_alloc_coherent() so the CPU observes the NPU-written
response without relying on streaming DMA direction.
Verified on Quantum Fiber W1700K (EN7581 + MT7996).
Fixes: 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox buffer")
Assisted-by: Cursor:composer-2
Signed-off-by: Daniel Pawlik <pawlik.dan@gmail.com>
---
drivers/net/ethernet/airoha/airoha_npu.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/airoha/airoha_npu.c b/drivers/net/ethernet/airoha/airoha_npu.c
index b679bed952de..d2f6c9c084b8 100644
--- a/drivers/net/ethernet/airoha/airoha_npu.c
+++ b/drivers/net/ethernet/airoha/airoha_npu.c
@@ -166,12 +166,21 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
u16 core = 0; /* FIXME */
u32 val, offset = core << 4;
dma_addr_t dma_addr;
+ void *dma_buf;
int ret;
- dma_addr = dma_map_single(npu->dev, p, size, DMA_BIDIRECTIONAL);
- ret = dma_mapping_error(npu->dev, dma_addr);
- if (ret)
- return ret;
+ /*
+ * Mailbox payloads are small and bidirectional (CPU sets the
+ * request, NPU writes the response). Streaming DMA_BIDIRECTIONAL
+ * mapping regresses EN7581+MT7996: MBOX reports success but
+ * WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0. Use a
+ * coherent bounce buffer so the CPU always sees the NPU response.
+ */
+ dma_buf = dma_alloc_coherent(npu->dev, size, &dma_addr, GFP_ATOMIC);
+ if (!dma_buf)
+ return -ENOMEM;
+
+ memcpy(dma_buf, p, size);
spin_lock_bh(&npu->cores[core].lock);
@@ -191,7 +200,9 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
spin_unlock_bh(&npu->cores[core].lock);
- dma_unmap_single(npu->dev, dma_addr, size, DMA_BIDIRECTIONAL);
+ if (!ret)
+ memcpy(p, dma_buf, size);
+ dma_free_coherent(npu->dev, size, dma_buf, dma_addr);
return ret;
}
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] net: airoha: npu: use coherent DMA for mailbox messages
2026-08-05 7:08 [PATCH] net: airoha: npu: use coherent DMA for mailbox messages Daniel Pawlik
@ 2026-08-05 9:59 ` Lorenzo Bianconi
2026-08-05 12:15 ` Daniel Pawlik
2026-08-06 7:26 ` [PATCH v2] " Daniel Pawlik
1 sibling, 1 reply; 5+ messages in thread
From: Lorenzo Bianconi @ 2026-08-05 9:59 UTC (permalink / raw)
To: Daniel Pawlik; +Cc: netdev, win847, linux-arm-kernel, linux-mediatek
[-- Attachment #1: Type: text/plain, Size: 2863 bytes --]
> Commit 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox
> buffer") switched airoha_npu_send_msg() to DMA_BIDIRECTIONAL so
> non-coherent CPUs invalidate caches before reading NPU GET responses.
>
> On EN7581 + MT7996 that change regresses probe: the mailbox completes
> successfully, but WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0 and
> mt76 never binds NPU offload. Healthy boards report 0.1111.
>
> Mailbox messages are tiny and already copied by the caller. Bounce
> through dma_alloc_coherent() so the CPU observes the NPU-written
> response without relying on streaming DMA direction.
>
> Verified on Quantum Fiber W1700K (EN7581 + MT7996).
>
> Fixes: 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox buffer")
> Assisted-by: Cursor:composer-2
> Signed-off-by: Daniel Pawlik <pawlik.dan@gmail.com>
> ---
> drivers/net/ethernet/airoha/airoha_npu.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/airoha/airoha_npu.c b/drivers/net/ethernet/airoha/airoha_npu.c
> index b679bed952de..d2f6c9c084b8 100644
> --- a/drivers/net/ethernet/airoha/airoha_npu.c
> +++ b/drivers/net/ethernet/airoha/airoha_npu.c
> @@ -166,12 +166,21 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
> u16 core = 0; /* FIXME */
> u32 val, offset = core << 4;
> dma_addr_t dma_addr;
> + void *dma_buf;
> int ret;
>
> - dma_addr = dma_map_single(npu->dev, p, size, DMA_BIDIRECTIONAL);
> - ret = dma_mapping_error(npu->dev, dma_addr);
> - if (ret)
> - return ret;
> + /*
> + * Mailbox payloads are small and bidirectional (CPU sets the
> + * request, NPU writes the response). Streaming DMA_BIDIRECTIONAL
> + * mapping regresses EN7581+MT7996: MBOX reports success but
> + * WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0. Use a
> + * coherent bounce buffer so the CPU always sees the NPU response.
> + */
> + dma_buf = dma_alloc_coherent(npu->dev, size, &dma_addr, GFP_ATOMIC);
> + if (!dma_buf)
> + return -ENOMEM;
I tried to reproduce the issue locally, but it does not occur for me.
Moreover, I guess dma_alloc_coherent() is not the right approach since it is
usually used for long-standing descriptors (e.g. tx/rx DMA descriptor rings).
Can you please provide more details about the hw you are running?
Regards,
Lorenzo
> +
> + memcpy(dma_buf, p, size);
>
> spin_lock_bh(&npu->cores[core].lock);
>
> @@ -191,7 +200,9 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
>
> spin_unlock_bh(&npu->cores[core].lock);
>
> - dma_unmap_single(npu->dev, dma_addr, size, DMA_BIDIRECTIONAL);
> + if (!ret)
> + memcpy(p, dma_buf, size);
> + dma_free_coherent(npu->dev, size, dma_buf, dma_addr);
>
> return ret;
> }
> --
> 2.55.0
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: airoha: npu: use coherent DMA for mailbox messages
2026-08-05 9:59 ` Lorenzo Bianconi
@ 2026-08-05 12:15 ` Daniel Pawlik
0 siblings, 0 replies; 5+ messages in thread
From: Daniel Pawlik @ 2026-08-05 12:15 UTC (permalink / raw)
To: Lorenzo Bianconi; +Cc: netdev, win847, linux-arm-kernel, linux-mediatek
Hi Lorenzo,
thanks for taking a look.
Hardware where I see the regression:
- Board: Gemtek W1700K (OpenWrt U-Boot layout), aka Quantum Fiber W1700K
- Airoha EN7581
- WiFi: MT7996 (eagle), NPU firmware
- Tree: OpenWrt main branch + patch related to update kernel to
6.18.42 - https://github.com/openwrt/openwrt/pull/24551
Please let me know what you need next (dmesg, DT snippet, etc.).
Thanks,
Daniel
śr., 5 sie 2026 o 11:59 Lorenzo Bianconi <lorenzo@kernel.org> napisał(a):
>
> > Commit 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox
> > buffer") switched airoha_npu_send_msg() to DMA_BIDIRECTIONAL so
> > non-coherent CPUs invalidate caches before reading NPU GET responses.
> >
> > On EN7581 + MT7996 that change regresses probe: the mailbox completes
> > successfully, but WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0 and
> > mt76 never binds NPU offload. Healthy boards report 0.1111.
> >
> > Mailbox messages are tiny and already copied by the caller. Bounce
> > through dma_alloc_coherent() so the CPU observes the NPU-written
> > response without relying on streaming DMA direction.
> >
> > Verified on Quantum Fiber W1700K (EN7581 + MT7996).
> >
> > Fixes: 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox buffer")
> > Assisted-by: Cursor:composer-2
> > Signed-off-by: Daniel Pawlik <pawlik.dan@gmail.com>
> > ---
> > drivers/net/ethernet/airoha/airoha_npu.c | 21 ++++++++++++++++-----
> > 1 file changed, 16 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/airoha/airoha_npu.c b/drivers/net/ethernet/airoha/airoha_npu.c
> > index b679bed952de..d2f6c9c084b8 100644
> > --- a/drivers/net/ethernet/airoha/airoha_npu.c
> > +++ b/drivers/net/ethernet/airoha/airoha_npu.c
> > @@ -166,12 +166,21 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
> > u16 core = 0; /* FIXME */
> > u32 val, offset = core << 4;
> > dma_addr_t dma_addr;
> > + void *dma_buf;
> > int ret;
> >
> > - dma_addr = dma_map_single(npu->dev, p, size, DMA_BIDIRECTIONAL);
> > - ret = dma_mapping_error(npu->dev, dma_addr);
> > - if (ret)
> > - return ret;
> > + /*
> > + * Mailbox payloads are small and bidirectional (CPU sets the
> > + * request, NPU writes the response). Streaming DMA_BIDIRECTIONAL
> > + * mapping regresses EN7581+MT7996: MBOX reports success but
> > + * WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0. Use a
> > + * coherent bounce buffer so the CPU always sees the NPU response.
> > + */
> > + dma_buf = dma_alloc_coherent(npu->dev, size, &dma_addr, GFP_ATOMIC);
> > + if (!dma_buf)
> > + return -ENOMEM;
>
> I tried to reproduce the issue locally, but it does not occur for me.
> Moreover, I guess dma_alloc_coherent() is not the right approach since it is
> usually used for long-standing descriptors (e.g. tx/rx DMA descriptor rings).
> Can you please provide more details about the hw you are running?
>
> Regards,
> Lorenzo
>
> > +
> > + memcpy(dma_buf, p, size);
> >
> > spin_lock_bh(&npu->cores[core].lock);
> >
> > @@ -191,7 +200,9 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
> >
> > spin_unlock_bh(&npu->cores[core].lock);
> >
> > - dma_unmap_single(npu->dev, dma_addr, size, DMA_BIDIRECTIONAL);
> > + if (!ret)
> > + memcpy(p, dma_buf, size);
> > + dma_free_coherent(npu->dev, size, dma_buf, dma_addr);
> >
> > return ret;
> > }
> > --
> > 2.55.0
> >
--
Z poważaniem,
Daniel Pawlik
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] net: airoha: npu: use coherent DMA for mailbox messages
2026-08-05 7:08 [PATCH] net: airoha: npu: use coherent DMA for mailbox messages Daniel Pawlik
2026-08-05 9:59 ` Lorenzo Bianconi
@ 2026-08-06 7:26 ` Daniel Pawlik
2026-08-06 8:02 ` Lorenzo Bianconi
1 sibling, 1 reply; 5+ messages in thread
From: Daniel Pawlik @ 2026-08-06 7:26 UTC (permalink / raw)
To: netdev; +Cc: lorenzo, win847, linux-arm-kernel, linux-mediatek, Daniel Pawlik
Commit 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox
buffer") switched airoha_npu_send_msg() to DMA_BIDIRECTIONAL so
non-coherent CPUs invalidate caches before reading NPU GET responses.
On EN7581 + MT7996 that change regresses probe: the mailbox completes
successfully, but WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0 and
mt76 never binds NPU offload. Healthy boards report 0.1111.
airoha_npu_send_msg() is also used from PPE foe_commit under
spin_lock_bh(), so per-message dma_alloc_coherent(GFP_ATOMIC) is a poor
fit. Allocate one device-managed coherent bounce buffer at probe and
reuse it under the existing per-core mailbox lock. That also keeps the
buffer valid if the NPU completes a write after a mailbox timeout.
Verified on Quantum Fiber / Gemtek W1700K (EN7581 + MT7996).
Fixes: 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox buffer")
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260805070851.2885888-1-pawlik.dan@gmail.com/
Assisted-by: Cursor:composer-2
Signed-off-by: Daniel Pawlik <pawlik.dan@gmail.com>
---
v2:
- allocate one coherent mailbox buffer at probe and reuse it under the
per-core lock instead of per-message dma_alloc_coherent(GFP_ATOMIC)
drivers/net/ethernet/airoha/airoha_npu.c | 31 +++++++++++++++++------
include/linux/soc/airoha/airoha_offload.h | 4 +++
2 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/airoha/airoha_npu.c b/drivers/net/ethernet/airoha/airoha_npu.c
index b679bed952de..dfa09fed907e 100644
--- a/drivers/net/ethernet/airoha/airoha_npu.c
+++ b/drivers/net/ethernet/airoha/airoha_npu.c
@@ -23,6 +23,8 @@
#define NPU_EN7581_FIRMWARE_RV32_MAX_SIZE 0x200000
#define NPU_EN7581_FIRMWARE_DATA_MAX_SIZE 0x10000
#define NPU_DUMP_SIZE 512
+/* Enough for struct ppe_mbox_data and small WLAN TLV payloads */
+#define AIROHA_NPU_MBOX_SIZE 256
#define REG_NPU_LOCAL_SRAM 0x0
@@ -165,17 +167,24 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
{
u16 core = 0; /* FIXME */
u32 val, offset = core << 4;
- dma_addr_t dma_addr;
int ret;
- dma_addr = dma_map_single(npu->dev, p, size, DMA_BIDIRECTIONAL);
- ret = dma_mapping_error(npu->dev, dma_addr);
- if (ret)
- return ret;
+ if (size > AIROHA_NPU_MBOX_SIZE)
+ return -EINVAL;
+ /*
+ * Mailbox payloads are bidirectional (CPU request, NPU response).
+ * On EN7581+MT7996, streaming DMA_BIDIRECTIONAL against the
+ * caller kzalloc() buffer can leave WLAN_FUNC_GET_WAIT_NPU_VERSION
+ * reading as 0.0 despite MBOX success. Reuse a probe-time coherent
+ * bounce buffer under the per-core lock (also used from PPE
+ * foe_commit under atomic context).
+ */
spin_lock_bh(&npu->cores[core].lock);
- regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(0) + offset, dma_addr);
+ memcpy(npu->mbox_buf, p, size);
+
+ regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(0) + offset, npu->mbox_dma);
regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(1) + offset, size);
regmap_read(npu->regmap, REG_CR_MBQ0_CTRL(2) + offset, &val);
regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(2) + offset, val + 1);
@@ -189,9 +198,10 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
if (!ret && FIELD_GET(MBOX_MSG_STATUS, val) != NPU_MBOX_SUCCESS)
ret = -EINVAL;
- spin_unlock_bh(&npu->cores[core].lock);
+ if (!ret)
+ memcpy(p, npu->mbox_buf, size);
- dma_unmap_single(npu->dev, dma_addr, size, DMA_BIDIRECTIONAL);
+ spin_unlock_bh(&npu->cores[core].lock);
return ret;
}
@@ -770,6 +780,11 @@ static int airoha_npu_probe(struct platform_device *pdev)
if (err)
return err;
+ npu->mbox_buf = dmam_alloc_coherent(dev, AIROHA_NPU_MBOX_SIZE,
+ &npu->mbox_dma, GFP_KERNEL);
+ if (!npu->mbox_buf)
+ return -ENOMEM;
+
err = airoha_npu_run_firmware(dev, base, &res);
if (err)
return dev_err_probe(dev, err, "failed to run npu firmware\n");
diff --git a/include/linux/soc/airoha/airoha_offload.h b/include/linux/soc/airoha/airoha_offload.h
index 7589fccfeef6..afd481233489 100644
--- a/include/linux/soc/airoha/airoha_offload.h
+++ b/include/linux/soc/airoha/airoha_offload.h
@@ -179,6 +179,10 @@ struct airoha_npu {
struct airoha_foe_stats __iomem *stats;
+ /* Coherent bounce buffer for mailbox cmd/rsp (airoha_npu_send_msg) */
+ void *mbox_buf;
+ dma_addr_t mbox_dma;
+
struct {
int (*ppe_init)(struct airoha_npu *npu);
int (*ppe_deinit)(struct airoha_npu *npu);
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] net: airoha: npu: use coherent DMA for mailbox messages
2026-08-06 7:26 ` [PATCH v2] " Daniel Pawlik
@ 2026-08-06 8:02 ` Lorenzo Bianconi
0 siblings, 0 replies; 5+ messages in thread
From: Lorenzo Bianconi @ 2026-08-06 8:02 UTC (permalink / raw)
To: Daniel Pawlik
Cc: netdev, win847, linux-arm-kernel, linux-mediatek,
Christian Marangi
[-- Attachment #1: Type: text/plain, Size: 5673 bytes --]
On Aug 06, Daniel Pawlik wrote:
> Commit 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox
> buffer") switched airoha_npu_send_msg() to DMA_BIDIRECTIONAL so
> non-coherent CPUs invalidate caches before reading NPU GET responses.
>
> On EN7581 + MT7996 that change regresses probe: the mailbox completes
> successfully, but WLAN_FUNC_GET_WAIT_NPU_VERSION still reads as 0.0 and
> mt76 never binds NPU offload. Healthy boards report 0.1111.
>
> airoha_npu_send_msg() is also used from PPE foe_commit under
> spin_lock_bh(), so per-message dma_alloc_coherent(GFP_ATOMIC) is a poor
> fit. Allocate one device-managed coherent bounce buffer at probe and
> reuse it under the existing per-core mailbox lock. That also keeps the
> buffer valid if the NPU completes a write after a mailbox timeout.
>
> Verified on Quantum Fiber / Gemtek W1700K (EN7581 + MT7996).
Hi Daniel,
I tested the issue you reported on a very similar hw (reported below) and it
works fine for me
- EN7581-mmc
- MT7996 SoC
@Christian: Is the issue occurring for you? I guess we should debug it a bit
more.
>
> Fixes: 6f884eb87a79 ("net: airoha: Fix DMA direction for NPU mailbox buffer")
> Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260805070851.2885888-1-pawlik.dan@gmail.com/
> Assisted-by: Cursor:composer-2
> Signed-off-by: Daniel Pawlik <pawlik.dan@gmail.com>
> ---
> v2:
> - allocate one coherent mailbox buffer at probe and reuse it under the
> per-core lock instead of per-message dma_alloc_coherent(GFP_ATOMIC)
>
> drivers/net/ethernet/airoha/airoha_npu.c | 31 +++++++++++++++++------
> include/linux/soc/airoha/airoha_offload.h | 4 +++
> 2 files changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/airoha/airoha_npu.c b/drivers/net/ethernet/airoha/airoha_npu.c
> index b679bed952de..dfa09fed907e 100644
> --- a/drivers/net/ethernet/airoha/airoha_npu.c
> +++ b/drivers/net/ethernet/airoha/airoha_npu.c
> @@ -23,6 +23,8 @@
> #define NPU_EN7581_FIRMWARE_RV32_MAX_SIZE 0x200000
> #define NPU_EN7581_FIRMWARE_DATA_MAX_SIZE 0x10000
> #define NPU_DUMP_SIZE 512
> +/* Enough for struct ppe_mbox_data and small WLAN TLV payloads */
> +#define AIROHA_NPU_MBOX_SIZE 256
Are you sure this is enough for all possible messages?
>
> #define REG_NPU_LOCAL_SRAM 0x0
>
> @@ -165,17 +167,24 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
> {
> u16 core = 0; /* FIXME */
> u32 val, offset = core << 4;
> - dma_addr_t dma_addr;
> int ret;
>
> - dma_addr = dma_map_single(npu->dev, p, size, DMA_BIDIRECTIONAL);
> - ret = dma_mapping_error(npu->dev, dma_addr);
> - if (ret)
> - return ret;
> + if (size > AIROHA_NPU_MBOX_SIZE)
> + return -EINVAL;
>
> + /*
> + * Mailbox payloads are bidirectional (CPU request, NPU response).
> + * On EN7581+MT7996, streaming DMA_BIDIRECTIONAL against the
> + * caller kzalloc() buffer can leave WLAN_FUNC_GET_WAIT_NPU_VERSION
> + * reading as 0.0 despite MBOX success. Reuse a probe-time coherent
> + * bounce buffer under the per-core lock (also used from PPE
> + * foe_commit under atomic context).
> + */
> spin_lock_bh(&npu->cores[core].lock);
>
> - regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(0) + offset, dma_addr);
> + memcpy(npu->mbox_buf, p, size);
Even if it is a just a theoretical issue (we just use core 0 at the moment), we
should have a per-core buffer since we can theoretically have concurrent messages
on different cores.
> +
> + regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(0) + offset, npu->mbox_dma);
> regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(1) + offset, size);
> regmap_read(npu->regmap, REG_CR_MBQ0_CTRL(2) + offset, &val);
> regmap_write(npu->regmap, REG_CR_MBQ0_CTRL(2) + offset, val + 1);
> @@ -189,9 +198,10 @@ static int airoha_npu_send_msg(struct airoha_npu *npu, int func_id,
> if (!ret && FIELD_GET(MBOX_MSG_STATUS, val) != NPU_MBOX_SUCCESS)
> ret = -EINVAL;
>
> - spin_unlock_bh(&npu->cores[core].lock);
> + if (!ret)
> + memcpy(p, npu->mbox_buf, size);
I do not like this double copy here. I guess we could pass a pointer for the
reply buffer to airoha_npu_send_msg() and avoid the copy in
airoha_npu_wlan_msg_get(). What do you think?
>
> - dma_unmap_single(npu->dev, dma_addr, size, DMA_BIDIRECTIONAL);
> + spin_unlock_bh(&npu->cores[core].lock);
>
> return ret;
> }
> @@ -770,6 +780,11 @@ static int airoha_npu_probe(struct platform_device *pdev)
> if (err)
> return err;
>
> + npu->mbox_buf = dmam_alloc_coherent(dev, AIROHA_NPU_MBOX_SIZE,
> + &npu->mbox_dma, GFP_KERNEL);
> + if (!npu->mbox_buf)
> + return -ENOMEM;
> +
> err = airoha_npu_run_firmware(dev, base, &res);
> if (err)
> return dev_err_probe(dev, err, "failed to run npu firmware\n");
> diff --git a/include/linux/soc/airoha/airoha_offload.h b/include/linux/soc/airoha/airoha_offload.h
> index 7589fccfeef6..afd481233489 100644
> --- a/include/linux/soc/airoha/airoha_offload.h
> +++ b/include/linux/soc/airoha/airoha_offload.h
> @@ -179,6 +179,10 @@ struct airoha_npu {
>
> struct airoha_foe_stats __iomem *stats;
>
> + /* Coherent bounce buffer for mailbox cmd/rsp (airoha_npu_send_msg) */
> + void *mbox_buf;
> + dma_addr_t mbox_dma;
you need to move them in airoha_npu_core struct. Please rename them to:
struct airoha_npu_core {
...
void *buf;
dma_addr_t addr;
...
};
Regards,
Lorenzo
> +
> struct {
> int (*ppe_init)(struct airoha_npu *npu);
> int (*ppe_deinit)(struct airoha_npu *npu);
> --
> 2.55.0
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-08-06 8:02 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2026-08-05 7:08 [PATCH] net: airoha: npu: use coherent DMA for mailbox messages Daniel Pawlik
2026-08-05 9:59 ` Lorenzo Bianconi
2026-08-05 12:15 ` Daniel Pawlik
2026-08-06 7:26 ` [PATCH v2] " Daniel Pawlik
2026-08-06 8:02 ` Lorenzo Bianconi
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