diff options
Diffstat (limited to 'drivers/net/ipa')
| -rw-r--r-- | drivers/net/ipa/gsi_trans.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c index 43f5f5d93cb0..92642030e735 100644 --- a/drivers/net/ipa/gsi_trans.c +++ b/drivers/net/ipa/gsi_trans.c @@ -397,15 +397,24 @@ void gsi_trans_cmd_add(struct gsi_trans *trans, void *buf, u32 size, /* assert(which < trans->tre_count); */ - /* Set the page information for the buffer. We also need to fill in - * the DMA address and length for the buffer (something dma_map_sg() - * normally does). + /* Commands are quite different from data transfer requests. + * Their payloads come from a pool whose memory is allocated + * using dma_alloc_coherent(). We therefore do *not* map them + * for DMA (unlike what we do for pages and skbs). + * + * When a transaction completes, the SGL is normally unmapped. + * A command transaction has direction DMA_NONE, which tells + * gsi_trans_complete() to skip the unmapping step. + * + * The only things we use directly in a command scatter/gather + * entry are the DMA address and length. We still need the SG + * table flags to be maintained though, so assign a NULL page + * pointer for that purpose. */ sg = &trans->sgl[which]; - - sg_set_buf(sg, buf, size); + sg_assign_page(sg, NULL); sg_dma_address(sg) = addr; - sg_dma_len(sg) = sg->length; + sg_dma_len(sg) = size; info = &trans->info[which]; info->opcode = opcode; |