The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 63ef91f24f9bfc70b6446319f6cabfd094481372 Mon Sep 17 00:00:00 2001

From: Marc Zyngier maz@kernel.org Date: Tue, 30 Jun 2020 11:05:46 +0100 Subject: [PATCH] PM / devfreq: rk3399_dmc: Fix kernel oops when rockchip,pmu is absent

Booting a recent kernel on a rk3399-based system (nanopc-t4), equipped with a recent u-boot and ATF results in an Oops due to a NULL pointer dereference.

This turns out to be due to the rk3399-dmc driver looking for an *undocumented* property (rockchip,pmu), and happily using a NULL pointer when the property isn't there.

Instead, make most of what was brought in with 9173c5ceb035 ("PM / devfreq: rk3399_dmc: Pass ODT and auto power down parameters to TF-A.") conditioned on finding this property in the device-tree, preventing the driver from exploding.

Cc: stable@vger.kernel.org Fixes: 9173c5ceb035 ("PM / devfreq: rk3399_dmc: Pass ODT and auto power down parameters to TF-A.") Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Chanwoo Choi cw00.choi@samsung.com

diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c index 24f04f78285b..027769e39f9b 100644 --- a/drivers/devfreq/rk3399_dmc.c +++ b/drivers/devfreq/rk3399_dmc.c @@ -95,18 +95,20 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,

mutex_lock(&dmcfreq->lock);

- if (target_rate >= dmcfreq->odt_dis_freq) - odt_enable = true; - - /* - * This makes a SMC call to the TF-A to set the DDR PD (power-down) - * timings and to enable or disable the ODT (on-die termination) - * resistors. - */ - arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, dmcfreq->odt_pd_arg0, - dmcfreq->odt_pd_arg1, - ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD, - odt_enable, 0, 0, 0, &res); + if (dmcfreq->regmap_pmu) { + if (target_rate >= dmcfreq->odt_dis_freq) + odt_enable = true; + + /* + * This makes a SMC call to the TF-A to set the DDR PD + * (power-down) timings and to enable or disable the + * ODT (on-die termination) resistors. + */ + arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, dmcfreq->odt_pd_arg0, + dmcfreq->odt_pd_arg1, + ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD, + odt_enable, 0, 0, 0, &res); + }

/* * If frequency scaling from low to high, adjust voltage first. @@ -371,13 +373,14 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev) }

node = of_parse_phandle(np, "rockchip,pmu", 0); - if (node) { - data->regmap_pmu = syscon_node_to_regmap(node); - of_node_put(node); - if (IS_ERR(data->regmap_pmu)) { - ret = PTR_ERR(data->regmap_pmu); - goto err_edev; - } + if (!node) + goto no_pmu; + + data->regmap_pmu = syscon_node_to_regmap(node); + of_node_put(node); + if (IS_ERR(data->regmap_pmu)) { + ret = PTR_ERR(data->regmap_pmu); + goto err_edev; }

regmap_read(data->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val); @@ -399,6 +402,7 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev) goto err_edev; };

+no_pmu: arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0, ROCKCHIP_SIP_CONFIG_DRAM_INIT, 0, 0, 0, 0, &res);