HACK: pmc: Add hack to force S0ix entry on lemp11

lemp11 sometimes fails to reach C10 and gets stuck in C0 during s2idle.
For some reason, sending a PMC SCI allows the CPU to go to C10.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

src/board/system76/common/acpi.c

@@ -19,6 +19,8 @@ extern uint8_t sci_extra;
 
 enum EcOs acpi_ecos = EC_OS_NONE;
 
+extern bool pmc_s0_hack;
+
 static uint8_t fcmd = 0;
 static uint8_t fdat = 0;
 static uint8_t fbuf[4] = { 0, 0, 0, 0 };
@@ -130,7 +132,11 @@ uint8_t acpi_read(uint8_t addr) {
 
         ACPI_16(0x42, battery_info.cycle_count);
 
-        ACPI_8(0x68, acpi_ecos);
+        case 0x68:
+            data = acpi_ecos;
+            // HACK: Kick PMC to fix suspend on lemp11
+            pmc_s0_hack = true;
+            break;
 
         case 0xBC:
             data = battery_get_start_threshold();

src/board/system76/common/pmc.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
+#include <arch/time.h>
 #include <arch/delay.h>
 #include <board/acpi.h>
 #include <board/gpio.h>
@@ -8,6 +9,12 @@
 #include <common/debug.h>
 #include <ec/espi.h>
 
+#ifndef PMC_S0IX_HACK
+#define PMC_S0IX_HACK 0
+#endif
+
+bool pmc_s0_hack = false;
+
 void pmc_init(void) {
     *(PMC_1.control) = 0x41;
     *(PMC_2.control) = 0x41;
@@ -180,9 +187,37 @@ static void pmc_on_output_empty(struct Pmc * pmc) {
     }
 }
 
+#if PMC_S0IX_HACK
+// HACK: Kick PMC to fix suspend on lemp11
+static void pmc_hack(void) {
+    static bool pmc_s0_hack2 = false;
+    static uint32_t last_time = 0;
+    // Get time the system requested S0ix (ACPI MS0X)
+    if (pmc_s0_hack) {
+        last_time = time_get();
+        pmc_s0_hack = false;
+        pmc_s0_hack2 = true;
+    }
+    uint32_t time = time_get();
+    // If SLP_S0# not asserted after 5 seconds, apply the hack
+    if ((time - last_time) >= 5000) {
+        if (pmc_s0_hack2 && gpio_get(&SLP_S0_N)) {
+            DEBUG("FIXME: PMC HACK\n");
+            pmc_sci(&PMC_1, 0x50);
+        }
+        pmc_s0_hack2 = false;
+        last_time = time;
+    }
+}
+#else
+static void pmc_hack(void) {}
+#endif
+
 void pmc_event(struct Pmc * pmc) {
     uint8_t sts;
 
+    pmc_hack();
+
     // Read command/data if available
     sts = pmc_status(pmc);
     if (sts & PMC_STS_IBF) {

src/board/system76/lemp11/board.mk

@@ -7,6 +7,8 @@ CFLAGS+=-DEC_ESPI=1
 
 # Use S0ix
 CFLAGS+=-DUSE_S0IX=1
+# Apply PMC hack for S0ix
+CFLAGS+=-DPMC_S0IX_HACK=1
 
 # Include keyboard
 KEYBOARD=14in_83