T8140: run the ISP as macOS does around a sleep (SLP_DDR wake stall)

arch/arm64/boot/dts/apple/t8140-pmgr.dtsi

@@ -274,7 +274,8 @@
 	 * enables between ISP_FE and ISP_SECURE.  Plain power
 	 * gating only: a local domain parked with DEV_DISABLE (the t8112
 	 * apple,force-disable pattern) never reached ACTIVE again on J700
-	 * (isp_cpu_core0 stuck at ACTUAL=0 on the second firmware boot).
+	 * (isp_cpu_core0 stuck at ACTUAL=0 on the second firmware boot).  No
+	 * automatic power management either: macOS writes them exactly 0xf.
 	 */
 	ps_sep: power-controller@c00 {
 		compatible = "apple,t8140-pmgr-pwrstate", "apple,t8103-pmgr-pwrstate";
@@ -290,6 +291,7 @@
 		reg = <0x4000 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_cpu";
 		power-domains = <&ps_isp_sys>;
 	};
@@ -299,6 +301,7 @@
 		reg = <0x4008 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_cpu_core0";
 		power-domains = <&ps_isp_cpu>;
 	};
@@ -308,6 +311,7 @@
 		reg = <0x4010 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_cpu_core1";
 		power-domains = <&ps_isp_cpu>;
 	};
@@ -317,6 +321,7 @@
 		reg = <0x4018 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_fe";
 		power-domains = <&ps_isp_sys>;
 	};
@@ -326,6 +331,7 @@
 		reg = <0x4020 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_dprx";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -335,6 +341,7 @@
 		reg = <0x4028 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_secure";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -344,6 +351,7 @@
 		reg = <0x4030 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_sts0";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -353,6 +361,7 @@
 		reg = <0x4038 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_sts1";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -362,6 +371,7 @@
 		reg = <0x4040 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_pearl";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -371,6 +381,7 @@
 		reg = <0x4048 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_be";
 		power-domains = <&ps_isp_fe>;
 	};
@@ -380,6 +391,7 @@
 		reg = <0x4050 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_clr";
 		power-domains = <&ps_isp_be>;
 	};
@@ -389,6 +401,7 @@
 		reg = <0x4058 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_cvd";
 		power-domains = <&ps_isp_be>;
 	};
@@ -398,6 +411,7 @@
 		reg = <0x4060 4>;
 		#power-domain-cells = <0>;
 		#reset-cells = <0>;
+		apple,no-auto-pm;
 		label = "isp_cvm";
 		power-domains = <&ps_isp_cvd>;
 	};

arch/arm64/boot/dts/apple/t8140.dtsi

@@ -2131,9 +2131,14 @@
 			interrupt-parent = <&aic>;
 			/* ADT [323 324 325 326 336]; 323 carries the IPC mailbox */
 			interrupts = <AIC_IRQ 323 IRQ_TYPE_LEVEL_HIGH>;
+			/*
+			 * In macOS's order: the camera sensor domains come up
+			 * after ISP_FE and before the rest of the pipeline.
+			 */
 			power-domains = <&ps_isp_sys>, <&ps_isp_cpu>,
 					<&ps_isp_cpu_core0>, <&ps_isp_cpu_core1>,
-					<&ps_isp_fe>, <&ps_isp_dprx>, <&ps_isp_secure>,
+					<&ps_isp_fe>, <&ps_ispsens0>, <&ps_ispsens1>,
+					<&ps_isp_dprx>, <&ps_isp_secure>,
 					<&ps_isp_sts0>, <&ps_isp_sts1>, <&ps_isp_pearl>,
 					<&ps_isp_be>, <&ps_isp_clr>, <&ps_isp_cvd>,
 					<&ps_isp_cvm>;

drivers/media/platform/apple/isp/isp-cam.c

@@ -587,11 +587,14 @@ int apple_isp_detect_camera(struct apple_isp *isp)
 
 	err = isp_detect_camera(isp);
 
-	/* Resident firmware stays up; the channel is set up per stream. */
+	/*
+	 * Resident firmware stays up, the channel set up per stream, unless it starts
+	 * again: then it's off until the first stream, as on macOS.
+	 */
 	if (isp->hw->resident_fw) {
-		if (err)
+		if (err || isp->hw->fw_restart)
 			apple_isp_firmware_halt(isp);
-		else
+		if (!err)
 			isp->camera_detected = true;
 		return err;
 	}

drivers/media/platform/apple/isp/isp-drv.c

@@ -969,6 +969,8 @@ static const struct apple_isp_hw apple_isp_hw_t8140 = {
 	.capture_meta_size = ISP_CAPTURE_META_SIZE_T8140,
 	.resident_fw = true,
 	.fw_restart = true,
+	/* As on macOS, the firmware first starts when a client opens the camera. */
+	.deferred_start = true,
 	.meta_exposure = true,
 };
 

drivers/media/platform/apple/isp/isp-fw.c

@@ -475,7 +475,13 @@ static void isp_firmware_shutdown_stage1(struct apple_isp *isp)
 		dev_warn(isp->dev, "coproc not in WFI before power-down (status 0x%x)\n",
 			 val);
 
-	isp_coproc_write32(isp, isp_coproc_control(isp), 0x0);
+	/*
+	 * macOS powers T8140's ISP off from WFI with the run bit still set. The sleep
+	 * engine's own restore of the ISP in a wake that kept DRAM up depends on it:
+	 * with the bit cleared that wake stalls until the SoC's watchdog resets it.
+	 */
+	if (isp->hw->gen != ISP_GEN_T8140)
+		isp_coproc_write32(isp, isp_coproc_control(isp), 0x0);
 
 	if (started) {
 		/* The request bit alone asks for it, and reads back once done */
@@ -1299,7 +1305,8 @@ int apple_isp_firmware_boot(struct apple_isp *isp)
 	if (err) {
 		dev_err(isp->dev, "failed to boot firmware: %d\n", err);
 		pm_runtime_put_sync(isp->dev);
-		if (isp->hw->resident_fw)
+		/* Firmware that starts again can be tried again at the next open. */
+		if (isp->hw->resident_fw && !isp->hw->fw_restart)
 			isp->fw_state = ISP_FW_DEAD;
 		return err;
 	}
@@ -1326,6 +1333,14 @@ void apple_isp_firmware_shutdown(struct apple_isp *isp)
 	if (isp->fw_state == ISP_FW_RUNNING)
 		synchronize_irq(isp->irq);
 	isp_free_released_surfaces(isp);
+
+	/*
+	 * Firmware that starts again goes down with the stream, as macOS's camera close
+	 * takes it, and boots again for the next one. A system sleep then finds it off:
+	 * stopped on the way into a sleep that keeps DRAM up, the SoC doesn't wake.
+	 */
+	if (isp->hw->fw_restart)
+		apple_isp_firmware_halt(isp);
 }
 
 /* Stop the firmware; resident firmware without hw->fw_restart stays down. */

drivers/pmdomain/apple/pmgr-pwrstate.c

@@ -134,6 +134,22 @@ static int apple_pmgr_ps_wait_parent(struct apple_pmgr_ps *ps, u32 *cur)
  * power-on then fails as it did before, and genpd, which ignores errors in
  * that phase, keeps the domain requested on.
  */
+/* Pulse the PS reset of a domain that is off with BUSY latched; it stays off. */
+static void apple_pmgr_ps_unlatch_off(struct apple_pmgr_ps *ps, u32 *cur)
+{
+	u32 off = *cur & ~(APPLE_PMGR_AUTO_ENABLE | APPLE_PMGR_FLAGS | APPLE_PMGR_BUSY |
+			   APPLE_PMGR_PS_RESET | APPLE_PMGR_DEV_DISABLE | APPLE_PMGR_PS_TARGET);
+
+	regmap_write(ps->regmap, ps->offset, off | APPLE_PMGR_PS_RESET);
+	regmap_read_poll_timeout_atomic(ps->regmap, ps->offset, *cur,
+					!(*cur & APPLE_PMGR_BUSY), 1, APPLE_PMGR_PS_SET_TIMEOUT);
+	regmap_write(ps->regmap, ps->offset, off);
+	regmap_read(ps->regmap, ps->offset, cur);
+	if (*cur & APPLE_PMGR_BUSY)
+		dev_warn_ratelimited(ps->dev, "PS %s: off with BUSY latched: %#x\n",
+				     ps->genpd.name, *cur);
+}
+
 static int apple_pmgr_ps_clear_latch(struct apple_pmgr_ps *ps, u32 reg, u32 *cur)
 {
 	u32 off = (reg & ~APPLE_PMGR_PS_TARGET) | APPLE_PMGR_PS_PWRGATE;
@@ -266,6 +282,19 @@ static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool a
 		}
 	}
 
+	/*
+	 * A domain can reach off with BUSY latched: on T8140 both ISP CPU cores do,
+	 * every time they go down under Linux. macOS leaves them off with it clear,
+	 * and the sleep engine, which powers them up itself in a wake that keeps DRAM
+	 * up, stalls on a latched one until its watchdog resets the SoC. Only a PS
+	 * reset clears it, and the domain is off, so pulse one as on the power-on
+	 * path (not in a system sleep transition, see apple_pmgr_ps_clear_latch()).
+	 */
+	if (!ret && pstate != APPLE_PMGR_PS_ACTIVE && (cur & APPLE_PMGR_BUSY) &&
+	    !FIELD_GET(APPLE_PMGR_PS_ACTUAL, cur) && !ps->system_sleep &&
+	    !ps->wait_parent && !ps->strict_state && !ps->externally_clocked)
+		apple_pmgr_ps_unlatch_off(ps, &cur);
+
 report:
 	if (ret < 0)
 		dev_err_ratelimited(ps->dev,

drivers/soc/apple/sleep.c

@@ -617,11 +617,11 @@ static bool sleep_slp_ddr_usb;
 static void __iomem *sleep_slp_ddr_word;
 
 /*
- * The SLP_DDR wake runs on the SoC-side state the system left. After a Linux boot it stalls in
- * the sleep engine, and once one deep sleep has rebuilt that state it gets through every time.
- * So the word stays clear, whatever the host votes, until a wake shows the deep path ran.
+ * The SLP_DDR wake runs on the SoC-side state the system left. The first one of a boot used to
+ * stall in the sleep engine, which came from the ISP's firmware boot at probe (see the ISP
+ * driver). Cleared while a deep path is owed, and set again by a wake that shows it ran.
  */
-static bool sleep_slp_ddr_ready;
+static bool sleep_slp_ddr_ready = true;
 
 /*
  * A coprocessor that runs through a sleep crashed. The AOP is the always-on master SLP_DDR keeps
@@ -672,9 +672,10 @@ void apple_sleep_coproc_crashed(struct device *dev)
 EXPORT_SYMBOL_GPL(apple_sleep_coproc_crashed);
 
 /*
- * After the camera ran, the next SLP_DDR wake stalled in the sleep engine, 6 of 6 times, whether
- * the ISP's firmware was stopped at the sleep or about 50 s before it; a deep sleep rebuilds
- * what it leaves, as after boot. So from the ISP's start, the next sleep takes the deep path.
+ * T8140's camera firmware doesn't start again after any SLP_DDR wake until a deep sleep: it
+ * boots, but its first command never completes. So from an ISP start, even a failed one, the
+ * next sleep takes the deep path: a camera used before a sleep works after it, and one that
+ * failed after a SLP_DDR wake works after the next sleep.
  */
 void apple_sleep_next_deep(struct device *dev)
 {