From:   David Mosberger-Tang <davidm@egauge.net>
Subject: [PATCH v2 50/50] wilc1000: add module parameter
 "disable_zero_copy_tx" to SPI driver
Date:   Thu, 23 Dec 2021 01:14:07 +0000 (UTC)
Message-Id: <20211223011358.4031459-51-davidm@egauge.net>
In-Reply-To: <20211223011358.4031459-1-davidm@egauge.net>
References: <20211223011358.4031459-1-davidm@egauge.net>
MIME-Version: 1.0
To:     Ajay Singh <ajay.kathat@microchip.com>
Cc:     Claudiu Beznea <claudiu.beznea@microchip.com>,
        Kalle Valo <kvalo@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        David Mosberger-Tang <davidm@egauge.net>
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Add a module parameter to disable the zero-copy transmit path.  This
is useful for testing and performance measurement, for example.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
---
 drivers/net/wireless/microchip/wilc1000/spi.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index 8d94f111ffc49..588cec326a74b 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -31,6 +31,11 @@ MODULE_PARM_DESC(enable_crc16,
 		 "\t\t\tData transfers can be large and the CPU-cycle cost\n"
 		 "\t\t\tof enabling this may be substantial.");
 
+static bool disable_zero_copy_tx;
+module_param(disable_zero_copy_tx, bool, 0644);
+MODULE_PARM_DESC(disable_zero_copy_tx,
+		 "Disable zero-copy when sending packets.");
+
 /*
  * For CMD_SINGLE_READ and CMD_INTERNAL_READ, WILC may insert one or
  * more zero bytes between the command response and the DATA Start tag
@@ -41,7 +46,7 @@ MODULE_PARM_DESC(enable_crc16,
  */
 #define WILC_SPI_RSP_HDR_EXTRA_DATA	8
 
-static const struct wilc_hif_func wilc_hif_spi;
+static struct wilc_hif_func wilc_hif_spi;
 
 static int wilc_spi_reset(struct wilc *wilc);
 static int wilc_spi_write_sk_buffs(struct wilc *wilc, u32 addr,
@@ -254,6 +259,9 @@ static int wilc_bus_probe(struct spi_device *spi)
 	if (!spi_priv)
 		return -ENOMEM;
 
+	if (!disable_zero_copy_tx)
+		wilc_hif_spi.hif_sk_buffs_tx = wilc_spi_write_sk_buffs;
+
 	ret = wilc_cfg80211_init(&wilc, &spi->dev, WILC_HIF_SPI, &wilc_hif_spi);
 	if (ret)
 		goto free;
@@ -1424,7 +1432,7 @@ static int wilc_spi_sync_ext(struct wilc *wilc, int nint)
 }
 
 /* Global spi HIF function table */
-static const struct wilc_hif_func wilc_hif_spi = {
+static struct wilc_hif_func wilc_hif_spi = {
 	.hif_init = wilc_spi_init,
 	.hif_deinit = wilc_spi_deinit,
 	.hif_read_reg = wilc_spi_read_reg,
@@ -1436,7 +1444,6 @@ static const struct wilc_hif_func wilc_hif_spi = {
 	.hif_read_size = wilc_spi_read_size,
 	.hif_block_tx_ext = wilc_spi_write,
 	.hif_block_rx_ext = wilc_spi_read,
-	.hif_sk_buffs_tx = wilc_spi_write_sk_buffs,
 	.hif_sync_ext = wilc_spi_sync_ext,
 	.hif_reset = wilc_spi_reset,
 };
-- 
2.25.1