[PATCH v3] net: qcom/emac: extend DMA mask to 46bits

[PATCH v3] net: qcom/emac: extend DMA mask to 46bits

[Wang Dongsheng]

Since PTP doesn't support yet, so extend the DMA address to 46bits.

Signed-off-by: Wang Dongsheng <wdsch86@gmail.com>
---
v3:
- Remove "Dynamic fix TPD_BUFFER_ADDR_H_SET size."
- Add comments for TPD_BUFFER_ADDR_H_SET.
v2:
- Changes PATCH subject.
- Dynamic fix TPD_BUFFER_ADDR_H_SET size.
- Modify DMA MASK to 46bits.
- Add Comments for DMA MASK.
---
 drivers/net/ethernet/qualcomm/emac/emac-mac.h | 3 ++-
 drivers/net/ethernet/qualcomm/emac/emac.c     | 7 +++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-mac.h b/drivers/net/ethernet/qualcomm/emac/emac-mac.h
index 5028fb4..4beedb8 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac-mac.h
+++ b/drivers/net/ethernet/qualcomm/emac/emac-mac.h
@@ -114,8 +114,9 @@ struct emac_tpd {
 #define TPD_INSTC_SET(tpd, val)		BITS_SET((tpd)->word[3], 17, 17, val)
 /* High-14bit Buffer Address, So, the 64b-bit address is
  * {DESC_CTRL_11_TX_DATA_HIADDR[17:0],(register) BUFFER_ADDR_H, BUFFER_ADDR_L}
+ * Extend TPD_BUFFER_ADDR_H to [31, 18], because we never enable timestamping.
  */
-#define TPD_BUFFER_ADDR_H_SET(tpd, val)	BITS_SET((tpd)->word[3], 18, 30, val)
+#define TPD_BUFFER_ADDR_H_SET(tpd, val)	BITS_SET((tpd)->word[3], 18, 31, val)
 /* Format D. Word offset from the 1st byte of this packet to start to calculate
  * the custom checksum.
  */
diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 70c92b6..a4b39d1 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -615,8 +615,11 @@ static int emac_probe(struct platform_device *pdev)
 	u32 reg;
 	int ret;
 
-	/* The TPD buffer address is limited to 45 bits. */
-	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(45));
+	/* The TPD buffer address is limited to:
+	 * 1. PTP:	45bits. (Driver doesn't support yet.)
+	 * 2. NON-PTP:	46bits.
+	 */
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(46));
 	if (ret) {
 		dev_err(&pdev->dev, "could not set DMA mask\n");
 		return ret;
-- 
2.7.4

Re: [PATCH v3] net: qcom/emac: extend DMA mask to 46bits

[Timur Tabi]

This is much better.  Can you give me a few days to test it on some 
internal platforms?

Also, this is a candidate for 4.16, so you need to wait until net-next 
is open anyway (http://vger.kernel.org/~davem/net-next.html).

On 11/20/17 7:48 AM, Wang Dongsheng wrote:
> Since PTP doesn't support yet, so extend the DMA address to 46bits.

This needs to be longer, since it's not clear that TPD3[31] is bot a 
timestamp bit and an address bit.  How about this:

Bit TPD3[31] is used as a timestamp bit if PTP is enabled,
but it's used as an address bit if PTP is disabled.  Since PTP isn't 
supported by the driver, we can extend the DMA address to 46 bits.



-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.