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Commit cd2830bf authored by Matt Wagantall's avatar Matt Wagantall
Browse files

soc: qcom: add scm-errata driver 



This driver exposes a debugfs interface intended for advanced
system debugging/profiling usecases where it may be desirable
to enable or disable certain hardware errata workarounds at
runtime, via an scm call.

Presently, a single debugfs node is implemented:
  /sys/kernel/debug/scm_errata/kryo_e74_e75
This allows Kryo errata 74 and 75 workarounds to be toggled
off or on (on affected devices) by echoing 0 or 1 to the file.

Change-Id: I6edf39757416130a7b716dcdab1a601f27dfac5a
Signed-off-by: default avatarMatt Wagantall <mattw@codeaurora.org>
parent 0487d9a0

drivers/soc/qcom/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -297,6 +297,17 @@ endchoice 


endif



config MSM_SCM_ERRATA

	depends on DEBUG_FS

	depends on MSM_SCM

	bool "Support for enabling/disabling errata workarounds via debugfs"

	help

	  Exposes a debugfs interface intended for advanced system debugging

	  where it may be desirable to enable or disable certain hardware

	  errata workarounds at runtime.



	  If unsure, say N.



config MSM_MPM_OF

       bool "Modem Power Manager"

       depends on OF

drivers/soc/qcom/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -64,7 +64,7 @@ obj-$(CONFIG_MSM_PIL) += peripheral-loader.o 
obj-$(CONFIG_MSM_PIL_SSR_GENERIC) += subsys-pil-tz.o

obj-$(CONFIG_MSM_PIL_MSS_QDSP6V5) += pil-q6v5.o pil-msa.o pil-q6v5-mss.o

obj-$(CONFIG_MSM_CORE_CTL_HELPER) += core_ctl_helper.o



obj-$(CONFIG_MSM_SCM_ERRATA) += scm-errata.o

obj-$(CONFIG_MSM_PERFORMANCE) += msm_performance.o



ifdef CONFIG_MSM_SUBSYSTEM_RESTART

drivers/soc/qcom/scm-errata.c

0 → 100644
+104 −0
Original line number Diff line number Diff line 
/* Copyright (c) 2015, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/smp.h>

#include <linux/debugfs.h>

#include <linux/cpu.h>

#include <soc/qcom/scm.h>



#define KRYO_ERRATA_74_75_ID	0x12

#define ERRATA_WA_DISABLE	0

#define ERRATA_WA_ENABLE	1



static struct dentry *debugfs_base;

static bool kryo_e74_e75_wa = true;



static void kryo_e74_e75_scm(void *enable)

{

	int ret;

	struct scm_desc desc = {0};



	if (!is_scm_armv8())

		return;



	desc.arginfo = SCM_ARGS(1);

	desc.args[0] = enable ? ERRATA_WA_ENABLE : ERRATA_WA_DISABLE;



	ret = scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_BOOT, KRYO_ERRATA_74_75_ID),

				&desc);

	if (ret)

		pr_err("Failed to %s ERRATA_74_75 workaround\n",

			enable ? "enable" : "disable");

}



static int kryo_e74_e75_set(void *data, u64 val)

{

	if ((val && kryo_e74_e75_wa) || (!val && !kryo_e74_e75_wa))

		return 0;



	kryo_e74_e75_wa = !!val;



	get_cpu();

	on_each_cpu(kryo_e74_e75_scm, (void *)kryo_e74_e75_wa, 1);

	put_cpu();



	return 0;

}



static int kryo_e74_e75_get(void *data, u64 *val)

{

	*val = kryo_e74_e75_wa;

	return 0;

}



DEFINE_SIMPLE_ATTRIBUTE(kryo_e74_e75_fops, kryo_e74_e75_get,

			kryo_e74_e75_set, "%llu\n");



static int scm_errata_notifier_callback(struct notifier_block *nfb,

					unsigned long action, void *hcpu)

{

	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		kryo_e74_e75_scm((void *)kryo_e74_e75_wa);

		break;

	}

	return 0;

}



static struct notifier_block scm_errata_notifier = {

	.notifier_call = scm_errata_notifier_callback,

};



static int __init scm_errata_init(void)

{

	int ret;



	debugfs_base = debugfs_create_dir("scm_errata", NULL);

	if (!debugfs_base)

		return -ENOMEM;



	if (!debugfs_create_file("kryo_e74_e75", S_IRUGO | S_IWUSR,

			debugfs_base, NULL, &kryo_e74_e75_fops))

		goto err;



	ret = register_hotcpu_notifier(&scm_errata_notifier);

	if (ret)

		goto err;



	return 0;

err:

	debugfs_remove_recursive(debugfs_base);

	return ret;

}

device_initcall(scm_errata_init);