[PATCH v2 03/17] firmware: turris-mox-rwtm: Use macro constant instead of hardcoded 4096

["Marek Behún" <kabel@kernel.org>]

The 4096 bytes limit in mox_hwrng_read() is due to the DMA buffer being
allocated to one PAGE_SIZE bytes. Use new local macro constant
RWTM_DMA_BUFFER_SIZE at allocation time and when used in mox_hwrng_read().

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 drivers/firmware/turris-mox-rwtm.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/turris-mox-rwtm.c b/drivers/firmware/turris-mox-rwtm.c
index 3f4758e03c81..b8deb13aed98 100644
--- a/drivers/firmware/turris-mox-rwtm.c
+++ b/drivers/firmware/turris-mox-rwtm.c
@@ -19,6 +19,8 @@
 
 #define DRIVER_NAME		"turris-mox-rwtm"
 
+#define RWTM_DMA_BUFFER_SIZE	PAGE_SIZE
+
 /*
  * The macros and constants below come from Turris Mox's rWTM firmware code.
  * This firmware is open source and it's sources can be found at
@@ -287,8 +289,8 @@ static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 	struct armada_37xx_rwtm_tx_msg msg;
 	int ret;
 
-	if (max > 4096)
-		max = 4096;
+	if (max > RWTM_DMA_BUFFER_SIZE)
+		max = RWTM_DMA_BUFFER_SIZE;
 
 	msg.command = MBOX_CMD_GET_RANDOM;
 	msg.args[0] = 1;
@@ -479,8 +481,8 @@ static int turris_mox_rwtm_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	rwtm->dev = dev;
-	rwtm->buf = dmam_alloc_coherent(dev, PAGE_SIZE, &rwtm->buf_phys,
-					GFP_KERNEL);
+	rwtm->buf = dmam_alloc_coherent(dev, RWTM_DMA_BUFFER_SIZE,
+					&rwtm->buf_phys, GFP_KERNEL);
 	if (!rwtm->buf)
 		return -ENOMEM;
 
-- 
2.44.2