[PATCH 2/4] platform/x86: pmc_atom: Check state of PMC 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 South 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 South complex
(controlled by PMC) are in a state that allows the SoC to enter S0i3
and prints an error message for any device in D0.

Note the pmc_atom code is enabled by CONFIG_X86_INTEL_LPSS which
already depends on ACPI.

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[hdegoede: Use acpi_s2idle_dev_ops, ignore fused off blocks, PMIC I2C]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/platform/x86/pmc_atom.c | 67 +++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/drivers/platform/x86/pmc_atom.c b/drivers/platform/x86/pmc_atom.c
index 93a6414c6611..e14d489fa6f9 100644
--- a/drivers/platform/x86/pmc_atom.c
+++ b/drivers/platform/x86/pmc_atom.c
@@ -6,6 +6,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/acpi.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/dmi.h>
@@ -17,6 +18,7 @@
 #include <linux/platform_device.h>
 #include <linux/pci.h>
 #include <linux/seq_file.h>
+#include <linux/suspend.h>
 
 struct pmc_bit_map {
 	const char *name;
@@ -448,6 +450,67 @@ static int pmc_setup_clks(struct pci_dev *pdev, void __iomem *pmc_regmap,
 	return 0;
 }
 
+#ifdef CONFIG_SUSPEND
+static void pmc_dev_state_check(u32 sts, const struct pmc_bit_map *sts_map,
+				u32 fd, const struct pmc_bit_map *fd_map,
+				u32 sts_possible_false_pos)
+{
+	int index;
+
+	for (index = 0; sts_map[index].name; index++) {
+		if (!(fd_map[index].bit_mask & fd) &&
+		    !(sts_map[index].bit_mask & sts)) {
+			if (sts_map[index].bit_mask & sts_possible_false_pos)
+				pm_pr_dbg("pmc_atom: %s is in D0 prior to s2idle\n",
+					  sts_map[index].name);
+			else
+				pr_err("pmc_atom: %s is in D0 prior to s2idle\n",
+				       sts_map[index].name);
+		}
+	}
+}
+
+static void pmc_s2idle_check(void)
+{
+	struct pmc_dev *pmc = &pmc_device;
+	const struct pmc_reg_map *m = pmc->map;
+	u32 func_dis, func_dis_2;
+	u32 d3_sts_0, d3_sts_1;
+	u32 false_pos_sts_0, false_pos_sts_1;
+
+	func_dis = pmc_reg_read(pmc, PMC_FUNC_DIS);
+	func_dis_2 = pmc_reg_read(pmc, PMC_FUNC_DIS_2);
+	d3_sts_0 = pmc_reg_read(pmc, PMC_D3_STS_0);
+	d3_sts_1 = pmc_reg_read(pmc, PMC_D3_STS_1);
+
+	/*
+	 * Some blocks are not used on lower-featured versions of the SoC and
+	 * always report D0, add these to false_pos mask to log at debug lvl.
+	 */
+	if (m->d3_sts_1	== byt_d3_sts_1_map) {
+		/* BYT */
+		false_pos_sts_0 = BIT_GBE | BIT_SATA | BIT_PCIE_PORT0 |
+			BIT_PCIE_PORT1 | BIT_PCIE_PORT2 | BIT_PCIE_PORT3 |
+			BIT_LPSS2_F5_I2C5;
+		false_pos_sts_1 = BIT_SMB | BIT_USH_SS_PHY | BIT_DFX;
+	} else {
+		/* CHT */
+		false_pos_sts_0 = BIT_GBE | BIT_SATA | BIT_LPSS2_F7_I2C7;
+		false_pos_sts_1 = BIT_SMB | BIT_STS_ISH;
+	}
+
+	/* Low part */
+	pmc_dev_state_check(d3_sts_0, m->d3_sts_0, func_dis, m->func_dis, false_pos_sts_0);
+
+	/* High part */
+	pmc_dev_state_check(d3_sts_1, m->d3_sts_1, func_dis_2, m->func_dis_2, false_pos_sts_1);
+}
+
+static struct acpi_s2idle_dev_ops pmc_s2idle_ops = {
+	.check = pmc_s2idle_check,
+};
+#endif
+
 static int pmc_setup_dev(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	struct pmc_dev *pmc = &pmc_device;
@@ -485,6 +548,10 @@ static int pmc_setup_dev(struct pci_dev *pdev, const struct pci_device_id *ent)
 		dev_warn(&pdev->dev, "platform clocks register failed: %d\n",
 			 ret);
 
+#ifdef CONFIG_SUSPEND
+	acpi_register_lps0_dev(&pmc_s2idle_ops);
+#endif
+
 	pmc->init = true;
 	return ret;
 }
-- 
2.43.0