[PATCH 5.17 0799/1126] net: stmmac: dwmac-qcom-ethqos: Enable RGMII functional clock on resume

Greg Kroah-Hartman
2022-04-05T09:13:45Z

From: Bjorn Andersson <bjorn.andersson@linaro.org>

[ Upstream commit ffba2123e1714a27e9362fda57c42155dda37efc ]

When the Qualcomm ethqos driver is properly described in its associated
GDSC power-domain, the hardware will be powered down and loose its state
between qcom_ethqos_probe() and stmmac_init_dma_engine().

The result of this is that the functional clock from the RGMII IO macro
is no longer provides and the DMA software reset in dwmac4_dma_reset()
will time out, due to lacking clock signal.

Re-enable the functional clock, as part of the Qualcomm specific clock
enablement sequence to avoid this problem.

The final clock configuration will be adjusted by ethqos_fix_mac_speed()
once the link is being brought up.

Fixes: a7c30e62d4b8 ("net: stmmac: Add driver for Qualcomm ethqos")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-and-reviewed-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Link: https://lore.kernel.org/r/20220323033255.2282930-1-bjorn.andersson@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
index 2ffa0a11eea5..569683f33804 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
@@ -460,6 +460,13 @@ static int ethqos_clks_config(void *priv, bool enabled)
dev_err(&ethqos->pdev->dev, "rgmii_clk enable failed\n");
return ret;
}
+
+ /* Enable functional clock to prevent DMA reset to timeout due
+ * to lacking PHY clock after the hardware block has been power
+ * cycled. The actual configuration will be adjusted once
+ * ethqos_fix_mac_speed() is invoked.
+ */
+ ethqos_set_func_clk_en(ethqos);
} else {
clk_disable_unprepare(ethqos->rgmii_clk);
}
--
2.34.1