[PATCH 1/2] accel: ethosu: Fix element size accounting for cmd stream validation
From: Rob Herring (Arm)
Date: Mon Jul 20 2026 - 19:15:02 EST
There are 2 issues with the element size handling in the command stream
validation which result in too small of a size calculated when the
element size is 16/32/64 bits.
For NHWC format, the element size is simply missing from the
calculation.
The bitfield for the element size is different between IFM/IFM2 and
OFM. IFM and IFM2 encode the precision in parameter bits 2:3, while OFM
uses bits 1:2.
Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver")
Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
---
drivers/accel/ethosu/ethosu_gem.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/accel/ethosu/ethosu_gem.c b/drivers/accel/ethosu/ethosu_gem.c
index 3401883e207f..1daff32610c7 100644
--- a/drivers/accel/ethosu/ethosu_gem.c
+++ b/drivers/accel/ethosu/ethosu_gem.c
@@ -194,7 +194,7 @@ static u64 dma_length(struct ethosu_validated_cmdstream_info *info,
static u64 feat_matrix_length(struct ethosu_validated_cmdstream_info *info,
struct feat_matrix *fm,
- u32 x, u32 y, u32 c)
+ u32 x, u32 y, u32 c, bool ofm)
{
u32 element_size, storage = fm->precision >> 14;
int tile = 0;
@@ -231,10 +231,11 @@ static u64 feat_matrix_length(struct ethosu_validated_cmdstream_info *info,
switch ((fm->precision >> 6) & 0x3) { // format
case 0: //nhwc:
- addr += x * fm->stride_x + c;
+ element_size = BIT((fm->precision >> (ofm ? 1 : 2)) & 0x3);
+ addr += x * fm->stride_x + c * element_size;
break;
case 1: //nhcwb16:
- element_size = BIT((fm->precision >> 1) & 0x3);
+ element_size = BIT((fm->precision >> (ofm ? 1 : 2)) & 0x3);
addr += (c / 16) * fm->stride_c + (16 * x + (c & 0xf)) * element_size;
break;
@@ -268,7 +269,7 @@ static int calc_sizes(struct drm_device *ddev,
return -EINVAL;
len = feat_matrix_length(info, &st->ifm, ifm_width,
- ifm_height, st->ifm.depth);
+ ifm_height, st->ifm.depth, false);
dev_dbg(ddev->dev, "op %d: IFM:%d:0x%llx-0x%llx\n",
op, st->ifm.region, st->ifm.base[0], len);
if (len == U64_MAX)
@@ -277,7 +278,7 @@ static int calc_sizes(struct drm_device *ddev,
if (ifm2) {
len = feat_matrix_length(info, &st->ifm2, st->ifm.depth,
- 0, st->ofm.depth);
+ 0, st->ofm.depth, false);
dev_dbg(ddev->dev, "op %d: IFM2:%d:0x%llx-0x%llx\n",
op, st->ifm2.region, st->ifm2.base[0], len);
if (len == U64_MAX)
@@ -309,7 +310,7 @@ static int calc_sizes(struct drm_device *ddev,
}
len = feat_matrix_length(info, &st->ofm, st->ofm.width,
- st->ofm.height[2], st->ofm.depth);
+ st->ofm.height[2], st->ofm.depth, true);
dev_dbg(ddev->dev, "op %d: OFM:%d:0x%llx-0x%llx\n",
op, st->ofm.region, st->ofm.base[0], len);
if (len == U64_MAX)
@@ -333,7 +334,7 @@ static int calc_sizes_elemwise(struct drm_device *ddev,
depth = st->ifm.broadcast & 0x4 ? 0 : st->ofm.depth;
len = feat_matrix_length(info, &st->ifm, width,
- height, depth);
+ height, depth, false);
dev_dbg(ddev->dev, "op %d: IFM:%d:0x%llx-0x%llx\n",
op, st->ifm.region, st->ifm.base[0], len);
if (len == U64_MAX)
@@ -346,7 +347,7 @@ static int calc_sizes_elemwise(struct drm_device *ddev,
depth = st->ifm2.broadcast & 0x4 ? 0 : st->ofm.depth;
len = feat_matrix_length(info, &st->ifm2, width,
- height, depth);
+ height, depth, false);
dev_dbg(ddev->dev, "op %d: IFM2:%d:0x%llx-0x%llx\n",
op, st->ifm2.region, st->ifm2.base[0], len);
if (len == U64_MAX)
@@ -354,7 +355,7 @@ static int calc_sizes_elemwise(struct drm_device *ddev,
}
len = feat_matrix_length(info, &st->ofm, st->ofm.width,
- st->ofm.height[2], st->ofm.depth);
+ st->ofm.height[2], st->ofm.depth, true);
dev_dbg(ddev->dev, "op %d: OFM:%d:0x%llx-0x%llx\n",
op, st->ofm.region, st->ofm.base[0], len);
if (len == U64_MAX)
--
2.53.0