[PATCH V3 2/3] qca_debug: Fix ethtool -G iface tx behavior

Stefan Wahren
2023-12-06T14:13:21Z

After calling ethtool -g it was not possible to adjust the TX ring
size again:

# ethtool -g eth1
Ring parameters for eth1:
Pre-set maximums:
RX: 4
RX Mini: n/a
RX Jumbo: n/a
TX: 10
Current hardware settings:
RX: 4
RX Mini: n/a
RX Jumbo: n/a
TX: 10
# ethtool -G eth1 tx 8
netlink error: Invalid argument

The reason for this is that the readonly setting rx_pending get
initialized and after that the range check in qcaspi_set_ringparam()
fails regardless of the provided parameter. So fix this by accepting
the exposed RX defaults. Instead of adding another magic number
better use a new define here.

Fixes: 291ab06ecf67 ("net: qualcomm: new Ethernet over SPI driver for QCA7000")
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
---
drivers/net/ethernet/qualcomm/qca_debug.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/qca_debug.c b/drivers/net/ethernet/qualcomm/qca_debug.c
index a5445252b0c4..1822f2ad8f0d 100644
--- a/drivers/net/ethernet/qualcomm/qca_debug.c
+++ b/drivers/net/ethernet/qualcomm/qca_debug.c
@@ -30,6 +30,8 @@

#define QCASPI_MAX_REGS 0x20

+#define QCASPI_RX_MAX_FRAMES 4
+
static const u16 qcaspi_spi_regs[] = {
SPI_REG_BFR_SIZE,
SPI_REG_WRBUF_SPC_AVA,
@@ -252,9 +254,9 @@ qcaspi_get_ringparam(struct net_device *dev, struct ethtool_ringparam *ring,
{
struct qcaspi *qca = netdev_priv(dev);

- ring->rx_max_pending = 4;
+ ring->rx_max_pending = QCASPI_RX_MAX_FRAMES;
ring->tx_max_pending = TX_RING_MAX_LEN;
- ring->rx_pending = 4;
+ ring->rx_pending = QCASPI_RX_MAX_FRAMES;
ring->tx_pending = qca->txr.count;
}

@@ -265,7 +267,7 @@ qcaspi_set_ringparam(struct net_device *dev, struct ethtool_ringparam *ring,
{
struct qcaspi *qca = netdev_priv(dev);

- if ((ring->rx_pending) ||
+ if (ring->rx_pending != QCASPI_RX_MAX_FRAMES ||
(ring->rx_mini_pending) ||
(ring->rx_jumbo_pending))
return -EINVAL;
--
2.34.1