From 051df5bd9bd02b93b6ea47e326ad6c570fa2469a Mon Sep 17 00:00:00 2001
From: "Se Wang (Patrick) Oh" <sewango@codeaurora.org>
Date: Wed, 21 Oct 2015 18:21:23 -0700
Subject: [PATCH] soc: qcom: add kryo_e76 debugfs node

To disable and enable Kryo hardware errata 76 workaround at
runtime, expose a debugfs interface. Wrote codes using e74/e76
API and data as a starting point.

/sys/kernel/debug/scm_errata/kryo_e76
This allows Kryo errata 76 workaround to be toggled
off or on (on affected devices) by echoing 0 or 1 to the file.

Change-Id: I3d682021aa98eef5421ac2e7578da02f2ea98081
Signed-off-by: Se Wang (Patrick) Oh <sewango@codeaurora.org>
---
 drivers/soc/qcom/scm-errata.c | 54 +++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 3 deletions(-)

diff --git a/drivers/soc/qcom/scm-errata.c b/drivers/soc/qcom/scm-errata.c
index 041f26b7b131..f68d88829336 100644
--- a/drivers/soc/qcom/scm-errata.c
+++ b/drivers/soc/qcom/scm-errata.c
@@ -17,12 +17,15 @@
 #include <linux/cpu.h>
 #include <soc/qcom/scm.h>
 
-#define KRYO_ERRATA_74_75_ID	0x12
+#define SCM_KRYO_ERRATA_ID	0x12
 #define ERRATA_WA_DISABLE	0
 #define ERRATA_WA_ENABLE	1
+#define ERRATA_74_75_ID_BIT	0x000
+#define ERRATA_76_ID_BIT	0x100
 
 static struct dentry *debugfs_base;
 static bool kryo_e74_e75_wa = true;
+static bool kryo_e76_wa;
 
 static void kryo_e74_e75_scm(void *enable)
 {
@@ -34,8 +37,9 @@ static void kryo_e74_e75_scm(void *enable)
 
 	desc.arginfo = SCM_ARGS(1);
 	desc.args[0] = enable ? ERRATA_WA_ENABLE : ERRATA_WA_DISABLE;
+	desc.args[0] |= ERRATA_74_75_ID_BIT;
 
-	ret = scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_BOOT, KRYO_ERRATA_74_75_ID),
+	ret = scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_BOOT, SCM_KRYO_ERRATA_ID),
 				&desc);
 	if (ret)
 		pr_err("Failed to %s ERRATA_74_75 workaround\n",
@@ -62,8 +66,49 @@ static int kryo_e74_e75_get(void *data, u64 *val)
 	return 0;
 }
 
+static void kryo_e76_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;
+	desc.args[0] |= ERRATA_76_ID_BIT;
+
+	ret = scm_call2_atomic(SCM_SIP_FNID(SCM_SVC_BOOT, SCM_KRYO_ERRATA_ID),
+				&desc);
+	if (ret)
+		pr_err("Failed to %s ERRATA_76 workaround\n",
+			enable ? "enable" : "disable");
+}
+
+static int kryo_e76_set(void *data, u64 val)
+{
+	if ((val && kryo_e76_wa) || (!val && !kryo_e76_wa))
+		return 0;
+
+	kryo_e76_wa = !!val;
+
+	get_cpu();
+	on_each_cpu(kryo_e76_scm, (void *)kryo_e76_wa, 1);
+	put_cpu();
+
+	return 0;
+}
+
+static int kryo_e76_get(void *data, u64 *val)
+{
+	*val = kryo_e76_wa;
+	return 0;
+}
+
 DEFINE_SIMPLE_ATTRIBUTE(kryo_e74_e75_fops, kryo_e74_e75_get,
 			kryo_e74_e75_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(kryo_e76_fops, kryo_e76_get,
+			kryo_e76_set, "%llu\n");
 
 static int scm_errata_notifier_callback(struct notifier_block *nfb,
 					unsigned long action, void *hcpu)
@@ -71,6 +116,7 @@ static int scm_errata_notifier_callback(struct notifier_block *nfb,
 	switch (action & ~CPU_TASKS_FROZEN) {
 	case CPU_STARTING:
 		kryo_e74_e75_scm((void *)kryo_e74_e75_wa);
+		kryo_e76_scm((void *)kryo_e76_wa);
 		break;
 	}
 	return 0;
@@ -91,7 +137,9 @@ static int __init scm_errata_init(void)
 	if (!debugfs_create_file("kryo_e74_e75", S_IRUGO | S_IWUSR,
 			debugfs_base, NULL, &kryo_e74_e75_fops))
 		goto err;
-
+	if (!debugfs_create_file("kryo_e76", S_IRUGO | S_IWUSR,
+			debugfs_base, NULL, &kryo_e76_fops))
+		goto err;
 	ret = register_hotcpu_notifier(&scm_errata_notifier);
 	if (ret)
 		goto err;