[PATCH v3] mtd: rawnand: cadence: support 64-bit slave dma interface

[Valentin Korenblit]

32-bit accesses on 64-bit sdma trigger sdma_err in intr_status register.

Check dma capabilities before reading/writing from/to sdma interface.

Link to discussion:
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/3NMACGIM5NDUBPXRT5RTBZON6LQE5A3B/

Signed-off-by: Valentin Korenblit <vkorenblit at sequans.com>

---

Changes v1 -> v2:
	- Replaced ioread64_rep by cadence_nand_readsq (suggested by Arnd)
	- Replaced iowrite64_rep by cadence_nand_writesq (suggested by Arnd)
	- Do not try to access 64-bit sdma if __raw_readq/__raw_writeq are not defined

Changes v2 -> v3:
	- Use readsq/writesq on 64-bit architectures (Arnd)
	- Detect issue on init instead of 1st transfer
---
 .../mtd/nand/raw/cadence-nand-controller.c    | 70 +++++++++++++++----
 1 file changed, 58 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/nand/raw/cadence-nand-controller.c b/drivers/mtd/nand/raw/cadence-nand-controller.c
index 9dac3ca69d57..7661a5cf1883 100644
--- a/drivers/mtd/nand/raw/cadence-nand-controller.c
+++ b/drivers/mtd/nand/raw/cadence-nand-controller.c
@@ -1184,6 +1184,14 @@ static int cadence_nand_hw_init(struct cdns_nand_ctrl *cdns_ctrl)
 	if (cadence_nand_read_bch_caps(cdns_ctrl))
 		return -EIO;
 
+#ifndef CONFIG_64BIT
+	if (cdns_ctrl->caps2.data_dma_width == 8) {
+		dev_err(cdns_ctrl->dev,
+			"cannot access 64-bit dma on !64-bit architectures");
+		return -EIO;
+	}
+#endif
+
 	/*
 	 * Set IO width access to 8.
 	 * It is because during SW device discovering width access
@@ -1882,17 +1890,36 @@ static int cadence_nand_read_buf(struct cdns_nand_ctrl *cdns_ctrl,
 		return status;
 
 	if (!cdns_ctrl->caps1->has_dma) {
-		int len_in_words = len >> 2;
+		u8 data_dma_width = cdns_ctrl->caps2.data_dma_width;
+
+		int len_in_words = (data_dma_width == 4) ? len >> 2 : len >> 3;
 
 		/* read alingment data */
-		ioread32_rep(cdns_ctrl->io.virt, buf, len_in_words);
+		if (data_dma_width == 4)
+			ioread32_rep(cdns_ctrl->io.virt, buf, len_in_words);
+#ifdef CONFIG_64BIT
+		else
+			readsq(cdns_ctrl->io.virt, buf, len_in_words);
+#endif
+
 		if (sdma_size > len) {
+			int read_bytes = (data_dma_width == 4) ?
+				len_in_words << 2 : len_in_words << 3;
+
 			/* read rest data from slave DMA interface if any */
-			ioread32_rep(cdns_ctrl->io.virt, cdns_ctrl->buf,
-				     sdma_size / 4 - len_in_words);
+			if (data_dma_width == 4)
+				ioread32_rep(cdns_ctrl->io.virt,
+					     cdns_ctrl->buf,
+					     sdma_size / 4 - len_in_words);
+#ifdef CONFIG_64BIT
+			else
+				readsq(cdns_ctrl->io.virt, cdns_ctrl->buf,
+				       sdma_size / 8 - len_in_words);
+#endif
+
 			/* copy rest of data */
-			memcpy(buf + (len_in_words << 2), cdns_ctrl->buf,
-			       len - (len_in_words << 2));
+			memcpy(buf + read_bytes, cdns_ctrl->buf,
+			       len - read_bytes);
 		}
 		return 0;
 	}
@@ -1936,16 +1963,35 @@ static int cadence_nand_write_buf(struct cdns_nand_ctrl *cdns_ctrl,
 		return status;
 
 	if (!cdns_ctrl->caps1->has_dma) {
-		int len_in_words = len >> 2;
+		u8 data_dma_width = cdns_ctrl->caps2.data_dma_width;
+
+		int len_in_words = (data_dma_width == 4) ? len >> 2 : len >> 3;
+
+		if (data_dma_width == 4)
+			iowrite32_rep(cdns_ctrl->io.virt, buf, len_in_words);
+#ifdef CONFIG_64BIT
+		else
+			writesq(cdns_ctrl->io.virt, buf, len_in_words);
+#endif
 
-		iowrite32_rep(cdns_ctrl->io.virt, buf, len_in_words);
 		if (sdma_size > len) {
+			int written_bytes = (data_dma_width == 4) ?
+				len_in_words << 2 : len_in_words << 3;
+
 			/* copy rest of data */
-			memcpy(cdns_ctrl->buf, buf + (len_in_words << 2),
-			       len - (len_in_words << 2));
+			memcpy(cdns_ctrl->buf, buf + written_bytes,
+			       len - written_bytes);
+
 			/* write all expected by nand controller data */
-			iowrite32_rep(cdns_ctrl->io.virt, cdns_ctrl->buf,
-				      sdma_size / 4 - len_in_words);
+			if (data_dma_width == 4)
+				iowrite32_rep(cdns_ctrl->io.virt,
+					      cdns_ctrl->buf,
+					      sdma_size / 4 - len_in_words);
+#ifdef CONFIG_64BIT
+			else
+				writesq(cdns_ctrl->io.virt, cdns_ctrl->buf,
+					sdma_size / 8 - len_in_words);
+#endif
 		}
 
 		return 0;
-- 
2.20.1

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