Merge tag 'mhi-for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi into char-misc-next

Manivannan writes:

MHI Host
========

- Added a new API mhi_power_down_keep_dev() to not destroy the struct dev
  associated with the MHI channels during MHI power down. This is useful in
  scenarios such as system suspend/hibernation where the probability of
  channels coming back is very high. So the PM maintainer suggested not to
  destroy the struct dev in those cases.

  This API is introduced for fixing the failure reported in the ath11k driver
  during resume from system suspend.

  NOTE: Due to the API dependency, the patch adding the API is pushed to an
  immutable branch (mhi-immutable) and merged into both mhi and ath trees. But
  the merge commit is not visible in mhi tree due to git being smart with
  'fast-forward'.

- Added an optional sysfs entry to force the MHI devices to enter the Emergency
  Download (EDL) mode to download the firmware from host.

- Added EDL mode support for Qcom SDX75/65/55 modems as per the MHI spec v1.2,
  Chapter 13.2. This involves writing a cookie to the EDL doorbell registers and
  then triggering the device reset from host.

* tag 'mhi-for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi:
  bus: mhi: host: pci_generic: Add generic edl_trigger to allow devices to enter EDL mode
  bus: mhi: host: Add a new API for getting channel doorbell offset
  bus: mhi: host: Add sysfs entry to force device to enter EDL
  bus: mhi: host: Add mhi_power_down_keep_dev() API to support system suspend/hibernation

7 files changed, 177 insertions, 13 deletions

diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi
index 1a47f9e0cc84..8b9698fa0beb 100644
--- a/Documentation/ABI/stable/sysfs-bus-mhi
+++ b/Documentation/ABI/stable/sysfs-bus-mhi
@@ -29,3 +29,16 @@ Description:	Initiates a SoC reset on the MHI controller.  A SoC reset is
                 This can be useful as a method of recovery if the device is
                 non-responsive, or as a means of loading new firmware as a
                 system administration task.
+
+What:           /sys/bus/mhi/devices/.../trigger_edl
+Date:           April 2024
+KernelVersion:  6.10
+Contact:        mhi@lists.linux.dev
+Description:    Writing a non-zero value to this file will force devices to
+                enter EDL (Emergency Download) mode. This entry only exists for
+                devices capable of entering the EDL mode using the standard EDL
+                triggering mechanism defined in the MHI spec v1.2. Once in EDL
+                mode, the flash programmer image can be downloaded to the
+                device to enter the flash programmer execution environment.
+                This can be useful if user wants to use QDL (Qualcomm Download,
+                which is used to download firmware over EDL) to update firmware.
diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index 44f934981de8..173f79918741 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -127,6 +127,30 @@ static ssize_t soc_reset_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(soc_reset);
 
+static ssize_t trigger_edl_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct mhi_device *mhi_dev = to_mhi_device(dev);
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	if (!val)
+		return -EINVAL;
+
+	ret = mhi_cntrl->edl_trigger(mhi_cntrl);
+	if (ret)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(trigger_edl);
+
 static struct attribute *mhi_dev_attrs[] = {
 	&dev_attr_serial_number.attr,
 	&dev_attr_oem_pk_hash.attr,
@@ -517,11 +541,9 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
 	dev_dbg(dev, "Initializing MHI registers\n");
 
 	/* Read channel db offset */
-	ret = mhi_read_reg(mhi_cntrl, base, CHDBOFF, &val);
-	if (ret) {
-		dev_err(dev, "Unable to read CHDBOFF register\n");
-		return -EIO;
-	}
+	ret = mhi_get_channel_doorbell_offset(mhi_cntrl, &val);
+	if (ret)
+		return ret;
 
 	if (val >= mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)) {
 		dev_err(dev, "CHDB offset: 0x%x is out of range: 0x%zx\n",
@@ -1018,6 +1040,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	if (ret)
 		goto err_release_dev;
 
+	if (mhi_cntrl->edl_trigger) {
+		ret = sysfs_create_file(&mhi_dev->dev.kobj, &dev_attr_trigger_edl.attr);
+		if (ret)
+			goto err_release_dev;
+	}
+
 	mhi_cntrl->mhi_dev = mhi_dev;
 
 	mhi_create_debugfs(mhi_cntrl);
@@ -1051,6 +1079,9 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 	mhi_deinit_free_irq(mhi_cntrl);
 	mhi_destroy_debugfs(mhi_cntrl);
 
+	if (mhi_cntrl->edl_trigger)
+		sysfs_remove_file(&mhi_dev->dev.kobj, &dev_attr_trigger_edl.attr);
+
 	destroy_workqueue(mhi_cntrl->hiprio_wq);
 	kfree(mhi_cntrl->mhi_cmd);
 	kfree(mhi_cntrl->mhi_event);
diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
index 5fe49311b8eb..aaad40a07f69 100644
--- a/drivers/bus/mhi/host/internal.h
+++ b/drivers/bus/mhi/host/internal.h
@@ -80,6 +80,7 @@ enum dev_st_transition {
 	DEV_ST_TRANSITION_FP,
 	DEV_ST_TRANSITION_SYS_ERR,
 	DEV_ST_TRANSITION_DISABLE,
+	DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE,
 	DEV_ST_TRANSITION_MAX,
 };
 
@@ -90,7 +91,8 @@ enum dev_st_transition {
 	dev_st_trans(MISSION_MODE,	"MISSION MODE")		\
 	dev_st_trans(FP,		"FLASH PROGRAMMER")	\
 	dev_st_trans(SYS_ERR,		"SYS ERROR")		\
-	dev_st_trans_end(DISABLE,	"DISABLE")
+	dev_st_trans(DISABLE,		"DISABLE")		\
+	dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)")
 
 extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX];
 #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index 15d657af9b5b..4de75674f193 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -1691,3 +1691,19 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)
 	}
 }
 EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer);
+
+int mhi_get_channel_doorbell_offset(struct mhi_controller *mhi_cntrl, u32 *chdb_offset)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	void __iomem *base = mhi_cntrl->regs;
+	int ret;
+
+	ret = mhi_read_reg(mhi_cntrl, base, CHDBOFF, chdb_offset);
+	if (ret) {
+		dev_err(dev, "Unable to read CHDBOFF register\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mhi_get_channel_doorbell_offset);
diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
index 51639bfcfec7..08844ee79654 100644
--- a/drivers/bus/mhi/host/pci_generic.c
+++ b/drivers/bus/mhi/host/pci_generic.c
@@ -27,12 +27,16 @@
 #define PCI_VENDOR_ID_THALES	0x1269
 #define PCI_VENDOR_ID_QUECTEL	0x1eac
 
+#define MHI_EDL_DB			91
+#define MHI_EDL_COOKIE			0xEDEDEDED
+
 /**
  * struct mhi_pci_dev_info - MHI PCI device specific information
  * @config: MHI controller configuration
  * @name: name of the PCI module
  * @fw: firmware path (if any)
  * @edl: emergency download mode firmware path (if any)
+ * @edl_trigger: capable of triggering EDL mode in the device (if supported)
  * @bar_num: PCI base address register to use for MHI MMIO register space
  * @dma_data_width: DMA transfer word size (32 or 64 bits)
  * @mru_default: default MRU size for MBIM network packets
@@ -44,6 +48,7 @@ struct mhi_pci_dev_info {
 	const char *name;
 	const char *fw;
 	const char *edl;
+	bool edl_trigger;
 	unsigned int bar_num;
 	unsigned int dma_data_width;
 	unsigned int mru_default;
@@ -292,6 +297,7 @@ static const struct mhi_pci_dev_info mhi_qcom_sdx75_info = {
 	.name = "qcom-sdx75m",
 	.fw = "qcom/sdx75m/xbl.elf",
 	.edl = "qcom/sdx75m/edl.mbn",
+	.edl_trigger = true,
 	.config = &modem_qcom_v2_mhiv_config,
 	.bar_num = MHI_PCI_DEFAULT_BAR_NUM,
 	.dma_data_width = 32,
@@ -302,6 +308,7 @@ static const struct mhi_pci_dev_info mhi_qcom_sdx65_info = {
 	.name = "qcom-sdx65m",
 	.fw = "qcom/sdx65m/xbl.elf",
 	.edl = "qcom/sdx65m/edl.mbn",
+	.edl_trigger = true,
 	.config = &modem_qcom_v1_mhiv_config,
 	.bar_num = MHI_PCI_DEFAULT_BAR_NUM,
 	.dma_data_width = 32,
@@ -312,6 +319,7 @@ static const struct mhi_pci_dev_info mhi_qcom_sdx55_info = {
 	.name = "qcom-sdx55m",
 	.fw = "qcom/sdx55m/sbl1.mbn",
 	.edl = "qcom/sdx55m/edl.mbn",
+	.edl_trigger = true,
 	.config = &modem_qcom_v1_mhiv_config,
 	.bar_num = MHI_PCI_DEFAULT_BAR_NUM,
 	.dma_data_width = 32,
@@ -928,6 +936,40 @@ static void health_check(struct timer_list *t)
 	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);
 }
 
+static int mhi_pci_generic_edl_trigger(struct mhi_controller *mhi_cntrl)
+{
+	void __iomem *base = mhi_cntrl->regs;
+	void __iomem *edl_db;
+	int ret;
+	u32 val;
+
+	ret = mhi_device_get_sync(mhi_cntrl->mhi_dev);
+	if (ret) {
+		dev_err(mhi_cntrl->cntrl_dev, "Failed to wakeup the device\n");
+		return ret;
+	}
+
+	pm_wakeup_event(&mhi_cntrl->mhi_dev->dev, 0);
+	mhi_cntrl->runtime_get(mhi_cntrl);
+
+	ret = mhi_get_channel_doorbell_offset(mhi_cntrl, &val);
+	if (ret)
+		goto err_get_chdb;
+
+	edl_db = base + val + (8 * MHI_EDL_DB);
+
+	mhi_cntrl->write_reg(mhi_cntrl, edl_db + 4, upper_32_bits(MHI_EDL_COOKIE));
+	mhi_cntrl->write_reg(mhi_cntrl, edl_db, lower_32_bits(MHI_EDL_COOKIE));
+
+	mhi_soc_reset(mhi_cntrl);
+
+err_get_chdb:
+	mhi_cntrl->runtime_put(mhi_cntrl);
+	mhi_device_put(mhi_cntrl->mhi_dev);
+
+	return ret;
+}
+
 static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
@@ -962,6 +1004,9 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	mhi_cntrl->runtime_put = mhi_pci_runtime_put;
 	mhi_cntrl->mru = info->mru_default;
 
+	if (info->edl_trigger)
+		mhi_cntrl->edl_trigger = mhi_pci_generic_edl_trigger;
+
 	if (info->sideband_wake) {
 		mhi_cntrl->wake_get = mhi_pci_wake_get_nop;
 		mhi_cntrl->wake_put = mhi_pci_wake_put_nop;
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index 8b40d3f01acc..11c0e751f223 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -468,7 +468,8 @@ error_mission_mode:
 }
 
 /* Handle shutdown transitions */
-static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
+static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
+				      bool destroy_device)
 {
 	enum mhi_pm_state cur_state;
 	struct mhi_event *mhi_event;
@@ -530,8 +531,16 @@ skip_mhi_reset:
 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
 	wake_up_all(&mhi_cntrl->state_event);
 
-	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
-	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	/*
+	 * Only destroy the 'struct device' for channels if indicated by the
+	 * 'destroy_device' flag. Because, during system suspend or hibernation
+	 * state, there is no need to destroy the 'struct device' as the endpoint
+	 * device would still be physically attached to the machine.
+	 */
+	if (destroy_device) {
+		dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
+		device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	}
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
 
@@ -821,7 +830,10 @@ void mhi_pm_st_worker(struct work_struct *work)
 			mhi_pm_sys_error_transition(mhi_cntrl);
 			break;
 		case DEV_ST_TRANSITION_DISABLE:
-			mhi_pm_disable_transition(mhi_cntrl);
+			mhi_pm_disable_transition(mhi_cntrl, false);
+			break;
+		case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE:
+			mhi_pm_disable_transition(mhi_cntrl, true);
 			break;
 		default:
 			break;
@@ -1175,7 +1187,8 @@ error_exit:
 }
 EXPORT_SYMBOL_GPL(mhi_async_power_up);
 
-void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
+			     bool destroy_device)
 {
 	enum mhi_pm_state cur_state, transition_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -1211,15 +1224,32 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 	write_unlock_irq(&mhi_cntrl->pm_lock);
 	mutex_unlock(&mhi_cntrl->pm_mutex);
 
-	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
+	if (destroy_device)
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE);
+	else
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE);
 
 	/* Wait for shutdown to complete */
 	flush_work(&mhi_cntrl->st_worker);
 
 	disable_irq(mhi_cntrl->irq[0]);
 }
+
+void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, true);
+}
 EXPORT_SYMBOL_GPL(mhi_power_down);
 
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
+			       bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, false);
+}
+EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
+
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
 {
 	int ret = mhi_async_power_up(mhi_cntrl);
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 77b8c0a26674..b573f15762f8 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -353,6 +353,7 @@ struct mhi_controller_config {
  * @read_reg: Read a MHI register via the physical link (required)
  * @write_reg: Write a MHI register via the physical link (required)
  * @reset: Controller specific reset function (optional)
+ * @edl_trigger: CB function to trigger EDL mode (optional)
  * @buffer_len: Bounce buffer length
  * @index: Index of the MHI controller instance
  * @bounce_buf: Use of bounce buffer
@@ -435,6 +436,7 @@ struct mhi_controller {
 	void (*write_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr,
 			  u32 val);
 	void (*reset)(struct mhi_controller *mhi_cntrl);
+	int (*edl_trigger)(struct mhi_controller *mhi_cntrl);
 
 	size_t buffer_len;
 	int index;
@@ -630,13 +632,29 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
 
 /**
- * mhi_power_down - Start MHI power down sequence
+ * mhi_power_down - Power down the MHI device and also destroy the
+ *                  'struct device' for the channels associated with it.
+ *                  See also mhi_power_down_keep_dev() which is a variant
+ *                  of this API that keeps the 'struct device' for channels
+ *                  (useful during suspend/hibernation).
  * @mhi_cntrl: MHI controller
  * @graceful: Link is still accessible, so do a graceful shutdown process
  */
 void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
 
 /**
+ * mhi_power_down_keep_dev - Power down the MHI device but keep the 'struct
+ *                           device' for the channels associated with it.
+ *                           This is a variant of 'mhi_power_down()' and
+ *                           useful in scenarios such as suspend/hibernation
+ *                           where destroying of the 'struct device' is not
+ *                           needed.
+ * @mhi_cntrl: MHI controller
+ * @graceful: Link is still accessible, so do a graceful shutdown process
+ */
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl, bool graceful);
+
+/**
  * mhi_unprepare_after_power_down - Free any allocated memory after power down
  * @mhi_cntrl: MHI controller
  */
@@ -798,4 +816,13 @@ int mhi_queue_skb(struct mhi_device *mhi_dev, enum dma_data_direction dir,
  */
 bool mhi_queue_is_full(struct mhi_device *mhi_dev, enum dma_data_direction dir);
 
+/**
+ * mhi_get_channel_doorbell_offset - Get the channel doorbell offset
+ * @mhi_cntrl: MHI controller
+ * @chdb_offset: Read channel doorbell offset
+ *
+ * Return: 0 if the read succeeds, a negative error code otherwise
+ */
+int mhi_get_channel_doorbell_offset(struct mhi_controller *mhi_cntrl, u32 *chdb_offset);
+
 #endif /* _MHI_H_ */