[PATCH] firmware: arm_ffa: Use the correct buffer size during RXTX_MAP

[Sebastian Ene <sebastianene@google.com>]

Don't use the discovered buffer size from an FFA_FEATURES call directly
since we can run on a system that has the PAGE_SIZE larger than the
returned size which makes the alloc_pages_exact for the buffer to be
rounded up.

Fixes: 61824feae5c0 ("firmware: arm_ffa: Fetch the Rx/Tx buffer size using ffa_features()")
Signed-off-by: Sebastian Ene <sebastianene@google.com>
---
 drivers/firmware/arm_ffa/driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index f2f94d4d533e..d0c926aca120 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -2078,7 +2078,7 @@ static int __init ffa_init(void)
 
 	ret = ffa_rxtx_map(virt_to_phys(drv_info->tx_buffer),
 			   virt_to_phys(drv_info->rx_buffer),
-			   rxtx_bufsz / FFA_PAGE_SIZE);
+			   DIV_ROUND_UP(rxtx_bufsz, PAGE_SIZE) / FFA_PAGE_SIZE);
 	if (ret) {
 		pr_err("failed to register FFA RxTx buffers\n");
 		goto free_pages;
-- 
2.53.0.1185.g05d4b7b318-goog