[PATCH v2 3/3] firmware: zynqmp-fpga: do not use DMA coherent memory for bitstream

[Michael Tretter]

Trying to do unaligned access of coherent memory on AArch64 will lead to
an abort. This can happen when the FPGA loader copies the bitstream to
the temporary buffer for the transfer to the FPGA.

Convert the driver to use regular memory for the temporary buffer to
prevent the issue.

Signed-off-by: Michael Tretter <m.tretter at pengutronix.de>
---
Changelog:

v2:
- drop dma_sync_single_for_device and use dma_map_single to flush
- fix missing free of DMA memory in case of mapping error
- use size_of(buf_size) to clarify extra space in buffer
---
 drivers/firmware/zynqmp-fpga.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/zynqmp-fpga.c b/drivers/firmware/zynqmp-fpga.c
index 667910479aa7..b76607f7eec1 100644
--- a/drivers/firmware/zynqmp-fpga.c
+++ b/drivers/firmware/zynqmp-fpga.c
@@ -203,7 +203,7 @@ static int fpgamgr_program_finish(struct firmware_handler *fh)
 	size_t body_length;
 	int header_length = 0;
 	enum xilinx_byte_order byte_order;
-	u64 addr;
+	dma_addr_t addr;
 	int status = 0;
 	u8 flags = ZYNQMP_FPGA_BIT_ONLY_BIN;
 
@@ -237,11 +237,10 @@ static int fpgamgr_program_finish(struct firmware_handler *fh)
 	/*
 	 * The PMU FW variants without the ZYNQMP_PM_FEATURE_SIZE_NOT_NEEDED
 	 * feature expect a pointer to the bitstream size, which is stored in
-	 * memory. Allocate some extra space at the end of the buffer for the
+	 * memory. Allocate extra space at the end of the buffer for the
 	 * bitstream size.
 	 */
-	buf_aligned = dma_alloc_coherent(body_length + sizeof(buf_size),
-					 DMA_ADDRESS_BROKEN);
+	buf_aligned = dma_alloc(body_length + sizeof(buf_size));
 	if (!buf_aligned) {
 		status = -ENOBUFS;
 		goto err_free;
@@ -254,8 +253,6 @@ static int fpgamgr_program_finish(struct firmware_handler *fh)
 	else
 		memcpy((u32 *)buf_aligned, body, body_length);
 
-	addr = (u64)buf_aligned;
-
 	if (mgr->features & ZYNQMP_PM_FEATURE_SIZE_NOT_NEEDED) {
 		buf_size = body_length;
 	} else {
@@ -263,11 +260,21 @@ static int fpgamgr_program_finish(struct firmware_handler *fh)
 		buf_size = addr + body_length;
 	}
 
-	status = mgr->eemi_ops->fpga_load(addr, buf_size, flags);
+	addr = dma_map_single(&mgr->dev, buf_aligned,
+			      body_length + sizeof(buf_size), DMA_TO_DEVICE);
+	if (dma_mapping_error(&mgr->dev, addr)) {
+		status = -EFAULT;
+		goto err_free_dma;
+	}
+
+	status = mgr->eemi_ops->fpga_load((u64)addr, buf_size, flags);
+	dma_unmap_single(&mgr->dev, addr, body_length + sizeof(buf_size),
+			 DMA_TO_DEVICE);
 	if (status < 0)
 		dev_err(&mgr->dev, "unable to load fpga\n");
 
-	dma_free_coherent(buf_aligned, 0, body_length + sizeof(buf_size));
+err_free_dma:
+	dma_free(buf_aligned);
 
  err_free:
 	free(mgr->buf);
-- 
2.30.2