[PATCH 5.4 049/168] net: thunderx: workaround BGX TX Underflow issue

Greg Kroah-Hartman
2020-03-10T12:50:03Z

From: Tim Harvey <tharvey@gateworks.com>

[ Upstream commit 971617c3b761c876d686a2188220a33898c90e99 ]

While it is not yet understood why a TX underflow can easily occur
for SGMII interfaces resulting in a TX wedge. It has been found that
disabling/re-enabling the LMAC resolves the issue.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Robert Jones <rjones@gateworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/cavium/thunder/thunder_bgx.c | 62 ++++++++++++++++++-
.../net/ethernet/cavium/thunder/thunder_bgx.h | 9 +++
2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
index 6cc100e7d5c07..76ff42ec3ae5e 100644
--- a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
+++ b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
@@ -410,10 +410,19 @@ void bgx_lmac_rx_tx_enable(int node, int bgx_idx, int lmacid, bool enable)
lmac = &bgx->lmac[lmacid];

cfg = bgx_reg_read(bgx, lmacid, BGX_CMRX_CFG);
- if (enable)
+ if (enable) {
cfg |= CMR_PKT_RX_EN | CMR_PKT_TX_EN;
- else
+
+ /* enable TX FIFO Underflow interrupt */
+ bgx_reg_modify(bgx, lmacid, BGX_GMP_GMI_TXX_INT_ENA_W1S,
+ GMI_TXX_INT_UNDFLW);
+ } else {
cfg &= ~(CMR_PKT_RX_EN | CMR_PKT_TX_EN);
+
+ /* Disable TX FIFO Underflow interrupt */
+ bgx_reg_modify(bgx, lmacid, BGX_GMP_GMI_TXX_INT_ENA_W1C,
+ GMI_TXX_INT_UNDFLW);
+ }
bgx_reg_write(bgx, lmacid, BGX_CMRX_CFG, cfg);

if (bgx->is_rgx)
@@ -1535,6 +1544,48 @@ static int bgx_init_phy(struct bgx *bgx)
return bgx_init_of_phy(bgx);
}

+static irqreturn_t bgx_intr_handler(int irq, void *data)
+{
+ struct bgx *bgx = (struct bgx *)data;
+ u64 status, val;
+ int lmac;
+
+ for (lmac = 0; lmac < bgx->lmac_count; lmac++) {
+ status = bgx_reg_read(bgx, lmac, BGX_GMP_GMI_TXX_INT);
+ if (status & GMI_TXX_INT_UNDFLW) {
+ pci_err(bgx->pdev, "BGX%d lmac%d UNDFLW\n",
+ bgx->bgx_id, lmac);
+ val = bgx_reg_read(bgx, lmac, BGX_CMRX_CFG);
+ val &= ~CMR_EN;
+ bgx_reg_write(bgx, lmac, BGX_CMRX_CFG, val);
+ val |= CMR_EN;
+ bgx_reg_write(bgx, lmac, BGX_CMRX_CFG, val);
+ }
+ /* clear interrupts */
+ bgx_reg_write(bgx, lmac, BGX_GMP_GMI_TXX_INT, status);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void bgx_register_intr(struct pci_dev *pdev)
+{
+ struct bgx *bgx = pci_get_drvdata(pdev);
+ int ret;
+
+ ret = pci_alloc_irq_vectors(pdev, BGX_LMAC_VEC_OFFSET,
+ BGX_LMAC_VEC_OFFSET, PCI_IRQ_ALL_TYPES);
+ if (ret < 0) {
+ pci_err(pdev, "Req for #%d msix vectors failed\n",
+ BGX_LMAC_VEC_OFFSET);
+ return;
+ }
+ ret = pci_request_irq(pdev, GMPX_GMI_TX_INT, bgx_intr_handler, NULL,
+ bgx, "BGX%d", bgx->bgx_id);
+ if (ret)
+ pci_free_irq(pdev, GMPX_GMI_TX_INT, bgx);
+}
+
static int bgx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
int err;
@@ -1550,7 +1601,7 @@ static int bgx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

pci_set_drvdata(pdev, bgx);

- err = pci_enable_device(pdev);
+ err = pcim_enable_device(pdev);
if (err) {
dev_err(dev, "Failed to enable PCI device\n");
pci_set_drvdata(pdev, NULL);
@@ -1604,6 +1655,8 @@ static int bgx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

bgx_init_hw(bgx);

+ bgx_register_intr(pdev);
+
/* Enable all LMACs */
for (lmac = 0; lmac < bgx->lmac_count; lmac++) {
err = bgx_lmac_enable(bgx, lmac);
@@ -1620,6 +1673,7 @@ static int bgx_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

err_enable:
bgx_vnic[bgx->bgx_id] = NULL;
+ pci_free_irq(pdev, GMPX_GMI_TX_INT, bgx);
err_release_regions:
pci_release_regions(pdev);
err_disable_device:
@@ -1637,6 +1691,8 @@ static void bgx_remove(struct pci_dev *pdev)
for (lmac = 0; lmac < bgx->lmac_count; lmac++)
bgx_lmac_disable(bgx, lmac);

+ pci_free_irq(pdev, GMPX_GMI_TX_INT, bgx);
+
bgx_vnic[bgx->bgx_id] = NULL;
pci_release_regions(pdev);
pci_disable_device(pdev);
diff --git a/drivers/net/ethernet/cavium/thunder/thunder_bgx.h b/drivers/net/ethernet/cavium/thunder/thunder_bgx.h
index 25888706bdcd1..cdea493921857 100644
--- a/drivers/net/ethernet/cavium/thunder/thunder_bgx.h
+++ b/drivers/net/ethernet/cavium/thunder/thunder_bgx.h
@@ -180,6 +180,15 @@
#define BGX_GMP_GMI_TXX_BURST 0x38228
#define BGX_GMP_GMI_TXX_MIN_PKT 0x38240
#define BGX_GMP_GMI_TXX_SGMII_CTL 0x38300
+#define BGX_GMP_GMI_TXX_INT 0x38500
+#define BGX_GMP_GMI_TXX_INT_W1S 0x38508
+#define BGX_GMP_GMI_TXX_INT_ENA_W1C 0x38510
+#define BGX_GMP_GMI_TXX_INT_ENA_W1S 0x38518
+#define GMI_TXX_INT_PTP_LOST BIT_ULL(4)
+#define GMI_TXX_INT_LATE_COL BIT_ULL(3)
+#define GMI_TXX_INT_XSDEF BIT_ULL(2)
+#define GMI_TXX_INT_XSCOL BIT_ULL(1)
+#define GMI_TXX_INT_UNDFLW BIT_ULL(0)

#define BGX_MSIX_VEC_0_29_ADDR 0x400000 /* +(0..29) << 4 */
#define BGX_MSIX_VEC_0_29_CTL 0x400008
--
2.20.1