[PATCH 4/4] x86/platform/atom: Check state of Punit managed devices on s2idle

[Hans de Goede <hdegoede@redhat.com>]

From: Johannes Stezenbach <js@sig21.net>

This is a port of "pm: Add pm suspend debug notifier for North IPs"
from the latte-l-oss branch of:
from https://github.com/MiCode/Xiaomi_Kernel_OpenSource latte-l-oss

With the new acpi_s2idle_dev_ops and acpi_register_lps0_dev()
functionality this can now finally be ported to the mainline kernel
without requiring adding non-upstreamable hooks into the cpu_idle
driver mechanism.

This adds a check that all hardware blocks in the North complex
(controlled by Punit) are in a state that allows the SoC to enter S0i3
and prints an error message for any device in D0.

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[hdegoede: Use acpi_s2idle_dev_ops]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 arch/x86/platform/atom/punit_atom_debug.c | 40 +++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/arch/x86/platform/atom/punit_atom_debug.c b/arch/x86/platform/atom/punit_atom_debug.c
index f8ed5f66cd20..efa4b188300d 100644
--- a/arch/x86/platform/atom/punit_atom_debug.c
+++ b/arch/x86/platform/atom/punit_atom_debug.c
@@ -7,6 +7,9 @@
  * Copyright (c) 2015, Intel Corporation.
  */
 
+#define pr_fmt(fmt) "punit_atom: " fmt
+
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/device.h>
@@ -102,10 +105,12 @@ static int punit_dev_state_show(struct seq_file *seq_file, void *unused)
 }
 DEFINE_SHOW_ATTRIBUTE(punit_dev_state);
 
+static const struct punit_device *punit_dev;
 static struct dentry *punit_dbg_file;
 
 static void punit_dbgfs_register(struct punit_device *punit_device)
 {
+	punit_dev = punit_device;
 	punit_dbg_file = debugfs_create_dir("punit_atom", NULL);
 
 	debugfs_create_file("dev_power_state", 0444, punit_dbg_file,
@@ -117,6 +122,35 @@ static void punit_dbgfs_unregister(void)
 	debugfs_remove_recursive(punit_dbg_file);
 }
 
+#if defined(CONFIG_ACPI) && defined(CONFIG_SUSPEND)
+static void punit_s2idle_check(void)
+{
+	const struct punit_device *punit_devp;
+	u32 punit_pwr_status, dstate;
+	int status;
+
+	for (punit_devp = punit_dev; punit_devp->name; punit_devp++) {
+		/* Skip MIO this is on till the very last moment */
+		if (punit_devp->reg == MIO_SS_PM)
+			continue;
+
+		status = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ,
+				       punit_devp->reg, &punit_pwr_status);
+		if (status) {
+			pr_err("%s read failed\n", punit_devp->name);
+		} else  {
+			dstate = (punit_pwr_status >> punit_devp->sss_pos) & 3;
+			if (!dstate)
+				pr_err("%s is in D0 prior to s2idle\n", punit_devp->name);
+		}
+	}
+}
+
+static struct acpi_s2idle_dev_ops punit_s2idle_ops = {
+	.check = punit_s2idle_check,
+};
+#endif
+
 #define X86_MATCH(model, data)						 \
 	X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, INTEL_FAM6_##model, \
 					   X86_FEATURE_MWAIT, data)
@@ -138,12 +172,18 @@ static int __init punit_atom_debug_init(void)
 		return -ENODEV;
 
 	punit_dbgfs_register((struct punit_device *)id->driver_data);
+#if defined(CONFIG_ACPI) && defined(CONFIG_SUSPEND)
+	acpi_register_lps0_dev(&punit_s2idle_ops);
+#endif
 
 	return 0;
 }
 
 static void __exit punit_atom_debug_exit(void)
 {
+#if defined(CONFIG_ACPI) && defined(CONFIG_SUSPEND)
+	acpi_unregister_lps0_dev(&punit_s2idle_ops);
+#endif
 	punit_dbgfs_unregister();
 }
 
-- 
2.43.0