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From:   Wang Dongsheng <dongsheng.wang@hxt-semitech.com>
To:     <timur@codeaurora.org>
CC:     <hpuranik@codeaurora.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Wang Dongsheng <dongsheng.wang@hxt-semitech.com>
Subject: [PATCH v4] net: qcom/emac: extend DMA mask to 46bits
Date:   Mon, 22 Jan 2018 20:25:06 -0800
Message-ID: <1516681506-8866-1-git-send-email-dongsheng.wang@hxt-semitech.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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.

Signed-off-by: Wang Dongsheng <dongsheng.wang@hxt-semitech.com>
---
v4:
- Changes: PATCH's description.
v3:
- Add: comments for TPD_BUFFER_ADDR_H_SET.
- Remove: "Dynamic fix TPD_BUFFER_ADDR_H_SET size."
v2:
- Add: Dynamic fix TPD_BUFFER_ADDR_H_SET size.
- Add: Comments for DMA MASK.
- Changes: PATCH subject.
- Modify: DMA MASK to 46bits.
---
 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 38c924bd..13235ba 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