[PATCH 2/2] net: macb: Add ethtool get_ringparam and set_ringparam functionality

From: Zach Brown
Date: Wed Oct 19 2016 - 10:57:13 EST


Some applications want to tune the size of the macb rx/tx ring buffers.
The ethtool set_ringparam function is the standard way of doing it.

Signed-off-by: Zach Brown <zach.brown@xxxxxx>
---
drivers/net/ethernet/cadence/macb.c | 59 +++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 644975d..e1847ce 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -37,11 +37,16 @@

#define MACB_RX_BUFFER_SIZE 128
#define RX_BUFFER_MULTIPLE 64 /* bytes */
+
#define DEFAULT_RX_RING_SIZE 512 /* must be power of 2 */
+#define MIN_RX_RING_SIZE 64
+#define MAX_RX_RING_SIZE 8192
#define RX_RING_BYTES(bp) (sizeof(struct macb_dma_desc) \
* (bp)->rx_ring_size)

#define DEFAULT_TX_RING_SIZE 512 /* must be power of 2 */
+#define MIN_TX_RING_SIZE 64
+#define MAX_TX_RING_SIZE 4096
#define TX_RING_BYTES(bp) (sizeof(struct macb_dma_desc) \
* (bp)->tx_ring_size)

@@ -2211,6 +2216,56 @@ static int macb_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
return 0;
}

+static void macb_get_ringparam(struct net_device *netdev,
+ struct ethtool_ringparam *ring)
+{
+ struct macb *bp = netdev_priv(netdev);
+
+ ring->rx_max_pending = MAX_RX_RING_SIZE;
+ ring->tx_max_pending = MAX_TX_RING_SIZE;
+
+ ring->rx_pending = bp->rx_ring_size;
+ ring->tx_pending = bp->tx_ring_size;
+}
+
+static int macb_set_ringparam(struct net_device *netdev,
+ struct ethtool_ringparam *ring)
+{
+ struct macb *bp = netdev_priv(netdev);
+ u32 new_rx_size, new_tx_size;
+ unsigned int reset = 0;
+
+ if ((ring->rx_mini_pending) || (ring->rx_jumbo_pending))
+ return -EINVAL;
+
+ new_rx_size = clamp_t(u32, ring->rx_pending,
+ MIN_RX_RING_SIZE, MAX_RX_RING_SIZE);
+ new_rx_size = roundup_pow_of_two(new_rx_size);
+
+ new_tx_size = clamp_t(u32, ring->tx_pending,
+ MIN_TX_RING_SIZE, MAX_TX_RING_SIZE);
+ new_tx_size = roundup_pow_of_two(new_tx_size);
+
+ if ((new_tx_size == bp->tx_ring_size) &&
+ (new_rx_size == bp->rx_ring_size)) {
+ /* nothing to do */
+ return 0;
+ }
+
+ if (netif_running(bp->dev)) {
+ reset = 1;
+ macb_close(bp->dev);
+ }
+
+ bp->rx_ring_size = new_rx_size;
+ bp->tx_ring_size = new_tx_size;
+
+ if (reset)
+ macb_open(bp->dev);
+
+ return 0;
+}
+
static const struct ethtool_ops macb_ethtool_ops = {
.get_regs_len = macb_get_regs_len,
.get_regs = macb_get_regs,
@@ -2220,6 +2275,8 @@ static const struct ethtool_ops macb_ethtool_ops = {
.set_wol = macb_set_wol,
.get_link_ksettings = phy_ethtool_get_link_ksettings,
.set_link_ksettings = phy_ethtool_set_link_ksettings,
+ .get_ringparam = macb_get_ringparam,
+ .set_ringparam = macb_set_ringparam,
};

static const struct ethtool_ops gem_ethtool_ops = {
@@ -2232,6 +2289,8 @@ static const struct ethtool_ops gem_ethtool_ops = {
.get_sset_count = gem_get_sset_count,
.get_link_ksettings = phy_ethtool_get_link_ksettings,
.set_link_ksettings = phy_ethtool_set_link_ksettings,
+ .get_ringparam = macb_get_ringparam,
+ .set_ringparam = macb_set_ringparam,
};

static int macb_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
--
2.7.4