[PATCH RFT v2 14/18] firmware: arm_ffa: Simplify the computation of transmit and fragment length

From: Sudeep Holla
Date: Tue Sep 19 2023 - 13:42:13 EST


The computation of endpoint memory access descriptor's composite memory
region descriptor offset is using COMPOSITE_CONSTITUENTS_OFFSET which is
unnecessary complicated. Composite memory region descriptor always follow
the endpoint memory access descriptor array and hence it is computed
accordingly. COMPOSITE_CONSTITUENTS_OFFSET is useless and wrong for any
input other than endpoint memory access descriptor count.

Let us drop the usage of COMPOSITE_CONSTITUENTS_OFFSET to simplify the
computation of total transmit and fragment length in the memory
transactions.

Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
drivers/firmware/arm_ffa/driver.c | 14 ++++++++------
include/linux/arm_ffa.h | 2 --
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 6312a7807d37..dadd56d17c20 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -443,23 +443,25 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
{
int rc = 0;
bool first = true;
+ u32 composite_offset;
phys_addr_t addr = 0;
+ struct ffa_mem_region *mem_region = buffer;
struct ffa_composite_mem_region *composite;
struct ffa_mem_region_addr_range *constituents;
struct ffa_mem_region_attributes *ep_mem_access;
- struct ffa_mem_region *mem_region = buffer;
u32 idx, frag_len, length, buf_sz = 0, num_entries = sg_nents(args->sg);

mem_region->tag = args->tag;
mem_region->flags = args->flags;
mem_region->sender_id = drv_info->vm_id;
mem_region->attributes = ffa_memory_attributes_get(func_id);
- ep_mem_access = &mem_region->ep_mem_access[0];
+ ep_mem_access = buffer + COMPOSITE_OFFSET(0);
+ composite_offset = COMPOSITE_OFFSET(args->nattrs);

for (idx = 0; idx < args->nattrs; idx++, ep_mem_access++) {
ep_mem_access->receiver = args->attrs[idx].receiver;
ep_mem_access->attrs = args->attrs[idx].attrs;
- ep_mem_access->composite_off = COMPOSITE_OFFSET(args->nattrs);
+ ep_mem_access->composite_off = composite_offset;
ep_mem_access->flag = 0;
ep_mem_access->reserved = 0;
}
@@ -468,13 +470,13 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
mem_region->reserved_1 = 0;
mem_region->ep_count = args->nattrs;

- composite = buffer + COMPOSITE_OFFSET(args->nattrs);
+ composite = buffer + composite_offset;
composite->total_pg_cnt = ffa_get_num_pages_sg(args->sg);
composite->addr_range_cnt = num_entries;
composite->reserved = 0;

- length = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, num_entries);
- frag_len = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, 0);
+ length = composite_offset + CONSTITUENTS_OFFSET(num_entries);
+ frag_len = composite_offset + CONSTITUENTS_OFFSET(0);
if (frag_len > max_fragsize)
return -ENXIO;

diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index f6df81f14b6d..748d0a83a4bc 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -356,8 +356,6 @@ struct ffa_mem_region {
(offsetof(struct ffa_mem_region, ep_mem_access[x]))
#define CONSTITUENTS_OFFSET(x) \
(offsetof(struct ffa_composite_mem_region, constituents[x]))
-#define COMPOSITE_CONSTITUENTS_OFFSET(x, y) \
- (COMPOSITE_OFFSET(x) + CONSTITUENTS_OFFSET(y))

struct ffa_mem_ops_args {
bool use_txbuf;

--
2.42.0