From 026b907d58c48b2ff2a4c04a67bb5f71ebda1f2d Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Thu, 8 Nov 2018 14:38:21 +0100 Subject: [PATCH] net: qca_spi: Add available buffer space verification Interferences on the SPI line could distort the response of available buffer space. So at least we should check that the response doesn't exceed the maximum available buffer space. In error case increase a new error counter and retry it later. This behavior avoids buffer errors in the QCA7000, which results in an unnecessary chip reset including packet loss. Signed-off-by: Stefan Wahren Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/qca_debug.c | 1 + drivers/net/ethernet/qualcomm/qca_spi.c | 16 +++++++++++++++- drivers/net/ethernet/qualcomm/qca_spi.h | 1 + 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/qualcomm/qca_debug.c b/drivers/net/ethernet/qualcomm/qca_debug.c index a9f1bc013364..1450f386bc65 100644 --- a/drivers/net/ethernet/qualcomm/qca_debug.c +++ b/drivers/net/ethernet/qualcomm/qca_debug.c @@ -61,6 +61,7 @@ static const char qcaspi_gstrings_stats[][ETH_GSTRING_LEN] = { "Transmit ring full", "SPI errors", "Write verify errors", + "Buffer available errors", }; #ifdef CONFIG_DEBUG_FS diff --git a/drivers/net/ethernet/qualcomm/qca_spi.c b/drivers/net/ethernet/qualcomm/qca_spi.c index d5310504f436..97f92953bdb9 100644 --- a/drivers/net/ethernet/qualcomm/qca_spi.c +++ b/drivers/net/ethernet/qualcomm/qca_spi.c @@ -289,6 +289,14 @@ qcaspi_transmit(struct qcaspi *qca) qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available); + if (available > QCASPI_HW_BUF_LEN) { + /* This could only happen by interferences on the SPI line. + * So retry later ... + */ + qca->stats.buf_avail_err++; + return -1; + } + while (qca->txr.skb[qca->txr.head]) { pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN; @@ -355,7 +363,13 @@ qcaspi_receive(struct qcaspi *qca) netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n", available); - if (available == 0) { + if (available > QCASPI_HW_BUF_LEN) { + /* This could only happen by interferences on the SPI line. + * So retry later ... + */ + qca->stats.buf_avail_err++; + return -1; + } else if (available == 0) { netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n"); return -1; } diff --git a/drivers/net/ethernet/qualcomm/qca_spi.h b/drivers/net/ethernet/qualcomm/qca_spi.h index 2d2c49726492..eb9af45fcc5e 100644 --- a/drivers/net/ethernet/qualcomm/qca_spi.h +++ b/drivers/net/ethernet/qualcomm/qca_spi.h @@ -74,6 +74,7 @@ struct qcaspi_stats { u64 ring_full; u64 spi_err; u64 write_verify_failed; + u64 buf_avail_err; }; struct qcaspi { -- 2.30.2