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Date:   Tue, 14 Apr 2020 20:20:17 +0200
From:   Marek Vasut <marex@...x.de>
To:     netdev@...r.kernel.org
Cc:     Marek Vasut <marex@...x.de>,
        "David S . Miller" <davem@...emloft.net>,
        Lukas Wunner <lukas@...ner.de>, Petr Stetiar <ynezz@...e.cz>,
        YueHaibing <yuehaibing@...wei.com>
Subject: [PATCH V4 07/19] net: ks8851: Remove ks8851_rdreg32()

The ks8851_rdreg32() is used only in one place, to read two registers
using a single read. To make it easier to support 16-bit accesses via
parallel bus later on, replace this single read with two 16-bit reads
from each of the registers and drop the ks8851_rdreg32() altogether.

If this has noticeable performance impact on the SPI variant of KS8851,
then we should consider using regmap to abstract the SPI and parallel
bus options and in case of SPI, permit regmap to merge register reads
of neighboring registers into single, longer, read.

Signed-off-by: Marek Vasut <marex@...x.de>
Cc: David S. Miller <davem@...emloft.net>
Cc: Lukas Wunner <lukas@...ner.de>
Cc: Petr Stetiar <ynezz@...e.cz>
Cc: YueHaibing <yuehaibing@...wei.com>
---
V2: No change
V3: No change
V4: Drop the NOTE from the comment, the performance is OK
---
 drivers/net/ethernet/micrel/ks8851.c | 25 ++-----------------------
 1 file changed, 2 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index c2f381a7b3f3..8f1cc05dc3c8 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -296,25 +296,6 @@ static unsigned ks8851_rdreg16(struct ks8851_net *ks, unsigned reg)
 	return le16_to_cpu(rx);
 }
 
-/**
- * ks8851_rdreg32 - read 32 bit register from device
- * @ks: The chip information
- * @reg: The register address
- *
- * Read a 32bit register from the chip.
- *
- * Note, this read requires the address be aligned to 4 bytes.
-*/
-static unsigned ks8851_rdreg32(struct ks8851_net *ks, unsigned reg)
-{
-	__le32 rx = 0;
-
-	WARN_ON(reg & 3);
-
-	ks8851_rdreg(ks, MK_OP(0xf, reg), (u8 *)&rx, 4);
-	return le32_to_cpu(rx);
-}
-
 /**
  * ks8851_soft_reset - issue one of the soft reset to the device
  * @ks: The device state.
@@ -508,7 +489,6 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
 	unsigned rxfc;
 	unsigned rxlen;
 	unsigned rxstat;
-	u32 rxh;
 	u8 *rxpkt;
 
 	rxfc = ks8851_rdreg8(ks, KS_RXFC);
@@ -527,9 +507,8 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
 	 */
 
 	for (; rxfc != 0; rxfc--) {
-		rxh = ks8851_rdreg32(ks, KS_RXFHSR);
-		rxstat = rxh & 0xffff;
-		rxlen = (rxh >> 16) & 0xfff;
+		rxstat = ks8851_rdreg16(ks, KS_RXFHSR);
+		rxlen = ks8851_rdreg16(ks, KS_RXFHBCR) & RXFHBCR_CNT_MASK;
 
 		netif_dbg(ks, rx_status, ks->netdev,
 			  "rx: stat 0x%04x, len 0x%04x\n", rxstat, rxlen);
-- 
2.25.1

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