dptf: Add support for Charger Performance States

This change generates the DPTF TCHG.PPSS table in the SSDT. This table
describes different charging rates which are available to use. DPTF
can pick different rates in order to passively cool (or not) the
system.

BUG=b:143539650
TEST=compiles

Change-Id: I6df6bfbac628fa4e4d313e38b8e6c53fce70a7f2
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41888
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/acpi/acpigen_dptf.c

@@ -7,6 +7,8 @@
 #define TOPLEVEL_DPTF_SCOPE		"\\_SB.DPTF"
 
 /* Defaults */
+#define DEFAULT_RAW_UNIT		"ma"
+
 enum {
 	ART_REVISION			= 0,
 	DEFAULT_PRIORITY		= 100,
@@ -280,3 +282,42 @@ void dptf_write_critical_policies(const struct dptf_critical_policy *policies, i
 		acpigen_pop_len(); /* Scope */
 	}
 }
+
+void dptf_write_charger_perf(const struct dptf_charger_perf *states, int max_count)
+{
+	char *pkg_count;
+	int i;
+
+	if (!max_count || !states[0].control)
+		return;
+
+	dptf_write_scope(DPTF_CHARGER);
+
+	/* PPSS - Participant Performance Supported States */
+	acpigen_write_method("PPSS", 0);
+	acpigen_emit_byte(RETURN_OP);
+
+	pkg_count = acpigen_write_package(0);
+	for (i = 0; i < max_count; ++i) {
+		if (!states[i].control)
+			break;
+
+		(*pkg_count)++;
+
+		/*
+		 * 0, 0, 0, 0, # Reserved
+		 * Control, Raw Performance, Raw Unit, 0 # Reserved
+		 */
+		acpigen_write_package(8);
+		write_zeros(4);
+		acpigen_write_integer(states[i].control);
+		acpigen_write_integer(states[i].raw_perf);
+		acpigen_write_string(DEFAULT_RAW_UNIT);
+		acpigen_write_integer(0);
+		acpigen_pop_len(); /* inner Package */
+	}
+
+	acpigen_pop_len(); /* outer Package */
+	acpigen_pop_len(); /* Method PPSS */
+	acpigen_pop_len(); /* Scope */
+}

src/drivers/intel/dptf/chip.h

@@ -11,6 +11,10 @@ struct drivers_intel_dptf_config {
 		struct dptf_critical_policy critical[DPTF_MAX_CRITICAL_POLICIES];
 		struct dptf_passive_policy passive[DPTF_MAX_PASSIVE_POLICIES];
 	} policies;
+
+	struct {
+		struct dptf_charger_perf charger_perf[DPTF_MAX_CHARGER_PERF_STATES];
+	} controls;
 };
 
 #endif /* _DRIVERS_INTEL_DPTF_CHIP_H_ */

src/drivers/intel/dptf/dptf.c

@@ -72,6 +72,9 @@ static void dptf_fill_ssdt(const struct device *dev)
 	dptf_write_critical_policies(config->policies.critical,
 				     DPTF_MAX_CRITICAL_POLICIES);
 
+	/* Controls */
+	dptf_write_charger_perf(config->controls.charger_perf, DPTF_MAX_CHARGER_PERF_STATES);
+
 	printk(BIOS_INFO, "\\_SB.DPTF: %s at %s\n", dev->chip_ops->name, dev_path(dev));
 }
 

src/include/acpi/acpigen_dptf.h

@@ -29,6 +29,9 @@ enum {
 	DPTF_MAX_ACTIVE_POLICIES	= (DPTF_PARTICIPANT_COUNT-1),
 	DPTF_MAX_PASSIVE_POLICIES	= (DPTF_PARTICIPANT_COUNT-1),
 	DPTF_MAX_CRITICAL_POLICIES	= (DPTF_PARTICIPANT_COUNT-1),
+
+	/* Maximum found by automatic inspection (awk) */
+	DPTF_MAX_CHARGER_PERF_STATES	= 10,
 };
 
 /* Active Policy */
@@ -76,6 +79,14 @@ struct dptf_critical_policy {
 	uint8_t temp;
 };
 
+/* Different levels of charging capability, chosen by passive policies */
+struct dptf_charger_perf {
+	/* Control value */
+	uint8_t control;
+	/* Charging performance, in mA */
+	uint16_t raw_perf;
+};
+
 /*
  * This function provides tables of temperature and corresponding fan or percent.  When the
  * temperature thresholds are met (_AC0 - _AC9), the fan is driven to corresponding percentage
@@ -98,6 +109,12 @@ void dptf_write_passive_policies(const struct dptf_passive_policy *policies, int
  */
 void dptf_write_critical_policies(const struct dptf_critical_policy *policies, int max_count);
 
+/*
+ * These are various performance levels for battery charging. They can be used in conjunction
+ * with passive policies to lower the charging rate when the _PSV threshold is met.
+ */
+void dptf_write_charger_perf(const struct dptf_charger_perf *perf, int max_count);
+
 /* Helper method to open the scope for a given participant. */
 void dptf_write_scope(enum dptf_participant participant);