[5/5] Bluetooth: bcm4377: Restore private PCI windows before J713 resume

MAINTAINERS

@@ -2769,6 +2769,7 @@ F:	Documentation/hwmon/macsmc-hwmon.rst
 F:	Documentation/power/apple-s2idle.rst
 F:	arch/arm64/boot/dts/apple/
 F:	drivers/bluetooth/hci_bcm4377.c
+F:	tools/asahi/bcm4377-sleep-config-tests.*
 F:	drivers/clk/clk-apple-nco.c
 F:	drivers/cpufreq/apple-soc-cpufreq.c
 F:	drivers/dma/apple-admac.c

drivers/bluetooth/hci_bcm4377.c

@@ -19,8 +19,10 @@
 #include <linux/of.h>
 #include <linux/wait.h>
 #include <linux/pci.h>
+#include <linux/soc/apple/radio-sleep.h>
 #include <linux/printk.h>
 #include <linux/property.h>
+#include <linux/suspend.h>
 #include <linux/workqueue.h>
 
 #include <linux/unaligned.h>
@@ -3098,6 +3100,15 @@ static int bcm4377_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 					hdev);
 }
 
+/* Final release runs after every device resume, including reversible unwind. */
+static void bcm4377_sleep_finish(struct device *dev)
+{
+	struct bcm4377_data *bcm4377 = pci_get_drvdata(to_pci_dev(dev));
+
+	WRITE_ONCE(bcm4377->setup_retry_blocked, false);
+	bcm4377_queue_setup_retry(bcm4377);
+}
+
 static int bcm4377_resume(struct device *dev);
 
 static int bcm4377_suspend(struct device *dev)
@@ -3106,6 +3117,12 @@ static int bcm4377_suspend(struct device *dev)
 	struct bcm4377_data *bcm4377 = pci_get_drvdata(pdev);
 	int ret;
 
+	ret = apple_radio_sleep_endpoint_prepare(dev, bcm4377_sleep_finish);
+	if (ret)
+		return ret;
+	if (apple_radio_sleep_owned(dev) && device_may_wakeup(dev))
+		return -EBUSY;
+
 	bcm4377_resume_recovery_stop(bcm4377);
 	WRITE_ONCE(bcm4377->setup_retry_blocked, true);
 	cancel_delayed_work_sync(&bcm4377->setup_retry_work);
@@ -3116,8 +3133,10 @@ static int bcm4377_suspend(struct device *dev)
 	ret = hci_suspend_dev(bcm4377->hdev);
 	if (ret) {
 		bcm4377->resume_powered = false;
-		WRITE_ONCE(bcm4377->setup_retry_blocked, false);
-		bcm4377_queue_setup_retry(bcm4377);
+		if (!apple_radio_sleep_owned(dev)) {
+			WRITE_ONCE(bcm4377->setup_retry_blocked, false);
+			bcm4377_queue_setup_retry(bcm4377);
+		}
 		return ret;
 	}
 
@@ -3152,8 +3171,11 @@ static int bcm4377_suspend(struct device *dev)
 	/* Flush the posted write before the system goes to sleep. */
 	ioread32(bcm4377->bar0 + BCM4377_BAR0_SLEEP_CONTROL);
 	bcm4377->quiesced = true;
-
-	return 0;
+	/* This records the command/readflush, not a firmware idle acknowledgment. */
+	ret = apple_radio_sleep_endpoint_suspended(dev);
+	if (ret)
+		bcm4377_resume(dev);
+	return ret;
 }
 
 static int bcm4377_resume(struct device *dev)
@@ -3163,6 +3185,10 @@ static int bcm4377_resume(struct device *dev)
 	unsigned long flags;
 	int ret;
 
+	ret = apple_radio_sleep_endpoint_resume(dev);
+	if (ret)
+		return ret;
+
 	if (bcm4377->wake_armed) {
 		disable_irq_wake(pdev->irq);
 		bcm4377->wake_armed = false;
@@ -3186,13 +3212,46 @@ static int bcm4377_resume(struct device *dev)
 	bcm4377->resume_powered = false;
 
 	ret = hci_resume_dev(bcm4377->hdev);
-	WRITE_ONCE(bcm4377->setup_retry_blocked, false);
-	if (!ret)
-		bcm4377_queue_setup_retry(bcm4377);
+	apple_radio_sleep_endpoint_resumed(dev, ret);
+	if (!apple_radio_sleep_owned(dev)) {
+		WRITE_ONCE(bcm4377->setup_retry_blocked, false);
+		if (!ret)
+			bcm4377_queue_setup_retry(bcm4377);
+	}
 	return ret;
 }
 
-static DEFINE_SIMPLE_DEV_PM_OPS(bcm4377_ops, bcm4377_suspend, bcm4377_resume);
+static int bcm4377_resume_noirq(struct device *dev)
+{
+	struct bcm4377_data *bcm4377 = pci_get_drvdata(to_pci_dev(dev));
+	u32 before, after;
+	int ret;
+
+	if (!apple_radio_sleep_owned(dev) || !pm_resume_via_firmware())
+		return 0;
+
+	/*
+	 * PERST resets the private BAR windows, which PCI's standard saved state
+	 * does not cover. Restore them before the IRQ handler or UNQUIESCE can
+	 * access the retained controller through those windows.
+	 */
+	ret = pci_read_config_dword(bcm4377->pdev, BCM4377_PCIECFG_BAR0_WINDOW1, &before);
+	if (!ret)
+		ret = bcm4377_init_cfg(bcm4377);
+	if (!ret)
+		ret = pci_read_config_dword(bcm4377->pdev, BCM4377_PCIECFG_BAR0_WINDOW1,
+					    &after);
+	if (ret || after != bcm4377->hw->bar0_window1)
+		panic("J713 Bluetooth PCI window restore failed: %d", ret);
+	dev_info(dev, "private PCI windows restored after sleep (%#x -> %#x)\n",
+		 before, after);
+	return 0;
+}
+
+static const struct dev_pm_ops bcm4377_ops = {
+	SYSTEM_SLEEP_PM_OPS(bcm4377_suspend, bcm4377_resume)
+	.resume_noirq = bcm4377_resume_noirq,
+};
 
 static const struct dmi_system_id bcm4377_dmi_board_table[] = {
 	{

tools/asahi/bcm4377-sleep-config-tests.c

@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <string.h>
+typedef uint32_t u32;
+#define BIT(n) (1U << (n))
+#define dev_info(...) ((void)0)
+struct device {
+	int unused;
+};
+struct pci_dev {
+	int unused;
+};
+struct hardware {
+	u32 bar0_window1, bar0_window2, bar0_core2_window2;
+	bool has_bar0_core2_window2, clear_pciecfg_subsystem_ctrl_bit19;
+};
+struct bcm4377_data {
+	struct pci_dev *pdev;
+	struct hardware *hw;
+};
+static struct pci_dev pci;
+static struct hardware hw = { 0x18002000, 0x18109000, 0x18106000, true, false };
+static struct bcm4377_data data = { &pci, &hw };
+static bool owned, physical, ignore_window;
+static unsigned int ops, writes, fail;
+static u32 cfg[64];
+static jmp_buf fatal;
+static struct pci_dev *to_pci_dev(struct device *d)
+{
+	(void)d;
+	return &pci;
+}
+static struct bcm4377_data *pci_get_drvdata(struct pci_dev *d)
+{
+	(void)d;
+	return &data;
+}
+static bool apple_radio_sleep_owned(struct device *d)
+{
+	(void)d;
+	return owned;
+}
+static bool pm_resume_via_firmware(void)
+{
+	return physical;
+}
+static int pci_read_config_dword(struct pci_dev *d, unsigned int off, u32 *v)
+{
+	(void)d;
+	if (++ops == fail)
+		return 0x87;
+	*v = cfg[off / 4];
+	return 0;
+}
+static int pci_write_config_dword(struct pci_dev *d, unsigned int off, u32 v)
+{
+	(void)d;
+	writes++;
+	if (++ops == fail)
+		return 0x87;
+	if (!(ignore_window && off == 0x80))
+		cfg[off / 4] = v;
+	return 0;
+}
+#define panic(...) longjmp(fatal, 1)
+/* ACTUAL */
+static void fresh(void)
+{
+	owned = physical = true;
+	ignore_window = false;
+	ops = writes = fail = 0;
+	memset(cfg, 0, sizeof(cfg));
+	cfg[0x88 / 4] = BIT(19) | 0x80;
+}
+int main(void)
+{
+	struct device dev = {};
+
+	fresh();
+
+	assert(!bcm4377_resume_noirq(&dev));
+	assert(cfg[0x80 / 4] == hw.bar0_window1);
+	assert(cfg[0x70 / 4] == hw.bar0_window2);
+	assert(cfg[0x74 / 4] == 0x18011000);
+	assert(cfg[0x78 / 4] == hw.bar0_core2_window2);
+	assert(cfg[0x84 / 4] == 0x19000000);
+	assert(cfg[0x88 / 4] == (BIT(19) | BIT(16) | 0x80));
+	unsigned int count = ops;
+
+	fresh();
+
+	owned = false;
+	assert(!bcm4377_resume_noirq(&dev));
+	assert(!ops);
+	fresh();
+	physical = false;
+	assert(!bcm4377_resume_noirq(&dev));
+	assert(!ops);
+	for (unsigned int i = 1; i <= count; i++) {
+		fresh();
+		fail = i;
+		if (!setjmp(fatal)) {
+			bcm4377_resume_noirq(&dev);
+			assert(0);
+		}
+		assert(ops == i);
+	}
+	fresh();
+	ignore_window = true;
+	if (!setjmp(fatal)) {
+		bcm4377_resume_noirq(&dev);
+		assert(0);
+	}
+	puts("PASS: private PCI windows, retained-path skip and restore failures");
+	return 0;
+}

tools/asahi/bcm4377-sleep-config-tests.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+"""Exercise private PCI-window restoration before Bluetooth resume IRQs."""
+
+from pathlib import Path
+import re
+import subprocess
+import tempfile
+
+root = Path(__file__).resolve().parents[2]
+source = (root / "drivers/bluetooth/hci_bcm4377.c").read_text()
+functions = []
+for name in ("bcm4377_init_cfg", "bcm4377_resume_noirq"):
+    match = re.search(
+        r"^static int " + name + r"\([^;]+?\{.*?\n\}", source, re.M | re.S
+    )
+    assert match, name
+    functions.append(match.group())
+constants = "\n".join(
+    line for line in source.splitlines() if line.startswith("#define BCM4377_PCIECFG_")
+)
+code = (
+    Path(__file__)
+    .with_suffix(".c")
+    .read_text()
+    .replace("/* ACTUAL */", constants + "\n" + "\n".join(functions))
+)
+with tempfile.TemporaryDirectory() as tmp:
+    c = Path(tmp) / "test.c"
+    c.write_text(code)
+    exe = Path(tmp) / "test"
+    subprocess.run(
+        ["cc", "-std=gnu11", "-Wall", "-Wextra", "-Werror", str(c), "-o", str(exe)],
+        check=True,
+    )
+    subprocess.run([str(exe)], check=True)