[V2][PATCH 5/5] spi: spi-zynqmp-gqspi: return -ENOMEM if dma_map_single fails

[quanyang . wang]

From: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>

The spi controller supports 44-bit address space on AXI in DMA mode,
so set dma_addr_t width to 44-bit to avoid using a swiotlb mapping.
In addition, if dma_map_single fails, it should return immediately
instead of continuing doing the DMA operation which bases on invalid
address.

This fixes the following crash which occurs in reading a big block
from flash:

[  123.633577] zynqmp-qspi ff0f0000.spi: swiotlb buffer is full (sz: 4194304 bytes), total 32768 (slots), used 0 (slots)
[  123.644230] zynqmp-qspi ff0f0000.spi: ERR:rxdma:memory not mapped
[  123.784625] Unable to handle kernel paging request at virtual address 00000000003fffc0
[  123.792536] Mem abort info:
[  123.795313]   ESR = 0x96000145
[  123.798351]   EC = 0x25: DABT (current EL), IL = 32 bits
[  123.803655]   SET = 0, FnV = 0
[  123.806693]   EA = 0, S1PTW = 0
[  123.809818] Data abort info:
[  123.812683]   ISV = 0, ISS = 0x00000145
[  123.816503]   CM = 1, WnR = 1
[  123.819455] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000805047000
[  123.825887] [00000000003fffc0] pgd=0000000803b45003, p4d=0000000803b45003, pud=0000000000000000
[  123.834586] Internal error: Oops: 96000145 [#1] PREEMPT SMP

Signed-off-by: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>
---
 drivers/spi/spi-zynqmp-gqspi.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 419bc1e6358b..328b6559bb19 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -733,7 +733,7 @@ static irqreturn_t zynqmp_qspi_irq(int irq, void *dev_id)
  * zynqmp_qspi_setuprxdma - This function sets up the RX DMA operation
  * @xqspi:	xqspi is a pointer to the GQSPI instance.
  */
-static void zynqmp_qspi_setuprxdma(struct zynqmp_qspi *xqspi)
+static int zynqmp_qspi_setuprxdma(struct zynqmp_qspi *xqspi)
 {
 	u32 rx_bytes, rx_rem, config_reg;
 	dma_addr_t addr;
@@ -747,7 +747,7 @@ static void zynqmp_qspi_setuprxdma(struct zynqmp_qspi *xqspi)
 		zynqmp_gqspi_write(xqspi, GQSPI_CONFIG_OFST, config_reg);
 		xqspi->mode = GQSPI_MODE_IO;
 		xqspi->dma_rx_bytes = 0;
-		return;
+		return 0;
 	}
 
 	rx_rem = xqspi->bytes_to_receive % 4;
@@ -755,8 +755,10 @@ static void zynqmp_qspi_setuprxdma(struct zynqmp_qspi *xqspi)
 
 	addr = dma_map_single(xqspi->dev, (void *)xqspi->rxbuf,
 			      rx_bytes, DMA_FROM_DEVICE);
-	if (dma_mapping_error(xqspi->dev, addr))
+	if (dma_mapping_error(xqspi->dev, addr)) {
 		dev_err(xqspi->dev, "ERR:rxdma:memory not mapped\n");
+		return -ENOMEM;
+	}
 
 	xqspi->dma_rx_bytes = rx_bytes;
 	xqspi->dma_addr = addr;
@@ -777,6 +779,8 @@ static void zynqmp_qspi_setuprxdma(struct zynqmp_qspi *xqspi)
 
 	/* Write the number of bytes to transfer */
 	zynqmp_gqspi_write(xqspi, GQSPI_QSPIDMA_DST_SIZE_OFST, rx_bytes);
+
+	return 0;
 }
 
 /**
@@ -813,11 +817,17 @@ static void zynqmp_qspi_write_op(struct zynqmp_qspi *xqspi, u8 tx_nbits,
  * @genfifoentry:	genfifoentry is pointer to the variable in which
  *			GENFIFO	mask is returned to calling function
  */
-static void zynqmp_qspi_read_op(struct zynqmp_qspi *xqspi, u8 rx_nbits,
+static int zynqmp_qspi_read_op(struct zynqmp_qspi *xqspi, u8 rx_nbits,
 				u32 genfifoentry)
 {
-	zynqmp_qspi_setuprxdma(xqspi);
+	int ret;
+
+	ret = zynqmp_qspi_setuprxdma(xqspi);
+	if (ret)
+		return ret;
 	zynqmp_qspi_fillgenfifo(xqspi, rx_nbits, genfifoentry);
+
+	return 0;
 }
 
 /**
@@ -1031,8 +1041,11 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 			xqspi->rxbuf = (u8 *)op->data.buf.in;
 			xqspi->bytes_to_receive = op->data.nbytes;
 			xqspi->bytes_to_transfer = 0;
-			zynqmp_qspi_read_op(xqspi, op->data.buswidth,
+			err = zynqmp_qspi_read_op(xqspi, op->data.buswidth,
 					    genfifoentry);
+			if (err)
+				goto return_err;
+
 			zynqmp_gqspi_write(xqspi, GQSPI_CONFIG_OFST,
 					   zynqmp_gqspi_read
 					   (xqspi, GQSPI_CONFIG_OFST) |
@@ -1159,6 +1172,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
 		goto clk_dis_all;
 	}
 
+	dma_set_mask(&pdev->dev, DMA_BIT_MASK(44));
 	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
 	ctlr->num_chipselect = GQSPI_DEFAULT_NUM_CS;
 	ctlr->mem_ops = &zynqmp_qspi_mem_ops;
-- 
2.25.1