From b4667e0445b9feffd69a43c2f0b458bae70db279 Mon Sep 17 00:00:00 2001
From: Florian Weber <Florian.Weber@live.de>
Date: Sat, 23 Nov 2024 00:42:47 +0100
Subject: [PATCH] drivers: rtio: bugfix

fixes the following:
- If a read SQE generates a CQE with an error before a buffer
has been allocated,
the flags of the sqe are not correctly translated into cqe flags.
- rtio_cqe_get_mempool_buffer(...) sets the *buff
to a non-zero value, even if no buffer is assigned

Signed-off-by: Florian Weber <Florian.Weber@live.de>
---
 include/zephyr/rtio/rtio.h | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/include/zephyr/rtio/rtio.h b/include/zephyr/rtio/rtio.h
index 9d117813185f..a7056f2e4ca7 100644
--- a/include/zephyr/rtio/rtio.h
+++ b/include/zephyr/rtio/rtio.h
@@ -1137,10 +1137,14 @@ static inline uint32_t rtio_cqe_compute_flags(struct rtio_iodev_sqe *iodev_sqe)
 	if (iodev_sqe->sqe.op == RTIO_OP_RX && iodev_sqe->sqe.flags & RTIO_SQE_MEMPOOL_BUFFER) {
 		struct rtio *r = iodev_sqe->r;
 		struct sys_mem_blocks *mem_pool = r->block_pool;
-		int blk_index = (iodev_sqe->sqe.rx.buf - mem_pool->buffer) >>
-				mem_pool->info.blk_sz_shift;
-		int blk_count = iodev_sqe->sqe.rx.buf_len >> mem_pool->info.blk_sz_shift;
+		unsigned int blk_index = 0;
+		unsigned int blk_count = 0;
 
+		if (iodev_sqe->sqe.rx.buf) {
+			blk_index = (iodev_sqe->sqe.rx.buf - mem_pool->buffer) >>
+				    mem_pool->info.blk_sz_shift;
+			blk_count = iodev_sqe->sqe.rx.buf_len >> mem_pool->info.blk_sz_shift;
+		}
 		flags = RTIO_CQE_FLAG_PREP_MEMPOOL(blk_index, blk_count);
 	}
 #else
@@ -1173,15 +1177,21 @@ static inline int z_impl_rtio_cqe_get_mempool_buffer(const struct rtio *r, struc
 {
 #ifdef CONFIG_RTIO_SYS_MEM_BLOCKS
 	if (RTIO_CQE_FLAG_GET(cqe->flags) == RTIO_CQE_FLAG_MEMPOOL_BUFFER) {
-		int blk_idx = RTIO_CQE_FLAG_MEMPOOL_GET_BLK_IDX(cqe->flags);
-		int blk_count = RTIO_CQE_FLAG_MEMPOOL_GET_BLK_CNT(cqe->flags);
+		unsigned int blk_idx = RTIO_CQE_FLAG_MEMPOOL_GET_BLK_IDX(cqe->flags);
+		unsigned int blk_count = RTIO_CQE_FLAG_MEMPOOL_GET_BLK_CNT(cqe->flags);
 		uint32_t blk_size = rtio_mempool_block_size(r);
 
-		*buff = r->block_pool->buffer + blk_idx * blk_size;
 		*buff_len = blk_count * blk_size;
-		__ASSERT_NO_MSG(*buff >= r->block_pool->buffer);
-		__ASSERT_NO_MSG(*buff <
+
+		if (blk_count > 0) {
+			*buff = r->block_pool->buffer + blk_idx * blk_size;
+
+			__ASSERT_NO_MSG(*buff >= r->block_pool->buffer);
+			__ASSERT_NO_MSG(*buff <
 				r->block_pool->buffer + blk_size * r->block_pool->info.num_blocks);
+		} else {
+			*buff = NULL;
+		}
 		return 0;
 	}
 	return -EINVAL;