@@ -11,14 +11,18 @@
#include <linux/dma-mapping.h>
#include <linux/hw_random.h>
#include <linux/mailbox_client.h>
+#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/sizes.h>
#include <linux/slab.h>
#define DRIVER_NAME "turris-mox-rwtm"
+#define RWTM_DMA_BUFFER_SIZE SZ_4K
+
/*
* 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 +291,7 @@ 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;
+ max = min(max, RWTM_DMA_BUFFER_SIZE);
msg.command = MBOX_CMD_GET_RANDOM;
msg.args[0] = 1;
@@ -479,8 +482,8 @@ 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;
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(). Use SZ_4K instead of PAGE_SIZE. Although PAGE_SIZE is never set to a larger value on Armada 3720, it theoretically could, and this would be a waste of space. Signed-off-by: Marek Behún <kabel@kernel.org> --- drivers/firmware/turris-mox-rwtm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)