[RFT][PATCH 4/7] net: dsa: microchip: Remove dev->txbuf

[Marek Vasut <marex@denx.de>]

Previous patches unconver that ksz_spi_write() is always ever called
with len = 1, 2 or 4. We can thus drop the if (len > SPI_TX_BUF_LEN)
check and we can also drop the allocation of the txbuf which is part
of the driver data. This wastes 256 bytes for no reason and can be
replaced with 8-byte stack allocated buffer, which is what this patch
does. This is an intermediate step though, which will go away after
regmap conversion.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: Woojung Huh <Woojung.Huh@microchip.com>
---
 drivers/net/dsa/microchip/ksz9477_spi.c | 10 ++++------
 drivers/net/dsa/microchip/ksz_priv.h    |  2 --
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477_spi.c b/drivers/net/dsa/microchip/ksz9477_spi.c
index 9ca150a472ea..69baf9677def 100644
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -65,11 +65,11 @@ static int ksz_spi_write(struct ksz_device *dev, u32 reg, void *data,
 			 unsigned int len)
 {
 	struct spi_device *spi = dev->priv;
+	u8 txbuf[8];
 
-	if (len > SPI_TX_BUF_LEN)
-		len = SPI_TX_BUF_LEN;
-	memcpy(&dev->txbuf[4], data, len);
-	return ksz9477_spi_write_reg(spi, reg, dev->txbuf, len);
+	memcpy(txbuf + 4, data, len);
+
+	return ksz9477_spi_write_reg(spi, reg, txbuf, len);
 }
 
 static int ksz_spi_read8(struct ksz_device *dev, u32 reg, u8 *val)
@@ -135,8 +135,6 @@ static int ksz9477_spi_probe(struct spi_device *spi)
 	if (spi->dev.platform_data)
 		dev->pdata = spi->dev.platform_data;
 
-	dev->txbuf = devm_kzalloc(dev->dev, 4 + SPI_TX_BUF_LEN, GFP_KERNEL);
-
 	ret = ksz9477_switch_register(dev);
 
 	/* Main DSA driver may not be started yet. */
diff --git a/drivers/net/dsa/microchip/ksz_priv.h b/drivers/net/dsa/microchip/ksz_priv.h
index c3a272505af1..3ab14ee0e36b 100644
--- a/drivers/net/dsa/microchip/ksz_priv.h
+++ b/drivers/net/dsa/microchip/ksz_priv.h
@@ -81,8 +81,6 @@ struct ksz_device {
 
 	u64 mib_value[TOTAL_SWITCH_COUNTER_NUM];
 
-	u8 *txbuf;
-
 	struct ksz_port *ports;
 	struct timer_list mib_read_timer;
 	struct work_struct mib_read;
-- 
2.19.2