Commit 63ef91f2 authored by Marc Zyngier's avatar Marc Zyngier Committed by Chanwoo Choi
Browse files

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 9173c5ce
("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: 9173c5ce ("PM / devfreq: rk3399_dmc: Pass ODT and auto power down parameters to TF-A.")
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent 92ed3019

drivers/devfreq/rk3399_dmc.c

+23 −19
Original line number Diff line number Diff line
@@ -95,18 +95,20 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq, 


	mutex_lock(&dmcfreq->lock);



	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.

		 * 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.
@@ -371,14 +373,15 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev) 
	}



	node = of_parse_phandle(np, "rockchip,pmu", 0);

	if (node) {

	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);

	ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
@@ -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);

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