[PATCH V2 0/2] soc: qcom: aoss: Expose send for generic usecase

[PATCH V2 0/2] soc: qcom: aoss: Expose send for generic usecase

[Deepak Kumar Singh]

Change from V1
Addressesed all review comments in previous set.

Deepak Kumar Singh (2):
  soc: qcom: aoss: Expose send for generic usecase
  soc: qcom: aoss: Add debugfs entry

 drivers/soc/qcom/qcom_aoss.c       | 91 +++++++++++++++++++++++++++++++++++++-
 include/linux/soc/qcom/qcom_aoss.h | 33 ++++++++++++++
 2 files changed, 123 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/soc/qcom/qcom_aoss.h

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V2 1/2] soc: qcom: aoss: Expose send for generic usecase

[Deepak Kumar Singh]

From: Deepak Kumar Singh <deesin@codeaurora.org>

Not all upcoming usecases will have an interface to allow the aoss
driver to hook onto. Expose the send api and create a get function to
enable drivers to send their own messages to aoss.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
---
 drivers/soc/qcom/qcom_aoss.c       | 50 +++++++++++++++++++++++++++++++++++++-
 include/linux/soc/qcom/qcom_aoss.h | 33 +++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/soc/qcom/qcom_aoss.h

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index 53acb94..0e397a7 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -8,10 +8,12 @@
 #include <linux/io.h>
 #include <linux/mailbox_client.h>
 #include <linux/module.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/thermal.h>
 #include <linux/slab.h>
+#include <linux/soc/qcom/qcom_aoss.h>
 
 #define QMP_DESC_MAGIC			0x0
 #define QMP_DESC_VERSION		0x4
@@ -61,6 +63,7 @@ struct qmp_cooling_device {
  * @mbox_chan: mailbox channel used to ring the doorbell on transmit
  * @offset: offset within @msgram where messages should be written
  * @size: maximum size of the messages to be transmitted
+ * @orphan: tarcks whether qmp handle is valid
  * @event: wait_queue for synchronization with the IRQ
  * @tx_lock: provides synchronization between multiple callers of qmp_send()
  * @qdss_clk: QDSS clock hw struct
@@ -76,6 +79,7 @@ struct qmp {
 
 	size_t offset;
 	size_t size;
+	atomic_t  orphan;
 
 	wait_queue_head_t event;
 
@@ -223,11 +227,17 @@ static bool qmp_message_empty(struct qmp *qmp)
  *
  * Return: 0 on success, negative errno on failure
  */
-static int qmp_send(struct qmp *qmp, const void *data, size_t len)
+int qmp_send(struct qmp *qmp, const void *data, size_t len)
 {
 	long time_left;
 	int ret;
 
+	if (WARN_ON(IS_ERR_OR_NULL(qmp) || !data))
+		return -EINVAL;
+
+	if (atomic_read(&qmp->orphan))
+		return -EINVAL;
+
 	if (WARN_ON(len + sizeof(u32) > qmp->size))
 		return -EINVAL;
 
@@ -261,6 +271,7 @@ static int qmp_send(struct qmp *qmp, const void *data, size_t len)
 
 	return ret;
 }
+EXPORT_SYMBOL(qmp_send);
 
 static int qmp_qdss_clk_prepare(struct clk_hw *hw)
 {
@@ -515,6 +526,40 @@ static void qmp_cooling_devices_remove(struct qmp *qmp)
 		thermal_cooling_device_unregister(qmp->cooling_devs[i].cdev);
 }
 
+/**
+ * qmp_get() - get a qmp handle from a device
+ * @dev: client device pointer
+ *
+ * Return: handle to qmp device on success, ERR_PTR() on failure
+ */
+struct qmp *qmp_get(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+	struct qmp *qmp;
+
+	if (!dev || !dev->of_node)
+		return ERR_PTR(-EINVAL);
+
+	np = of_parse_phandle(dev->of_node, "qcom,qmp", 0);
+	if (!np)
+		return ERR_PTR(-ENODEV);
+
+	pdev = of_find_device_by_node(np);
+	if (!pdev)
+		return ERR_PTR(-EINVAL);
+
+	qmp = platform_get_drvdata(pdev);
+	return qmp ? qmp : ERR_PTR(-EPROBE_DEFER);
+}
+EXPORT_SYMBOL(qmp_get);
+
+void qmp_put(struct platform_device *pdev)
+{
+	platform_device_put(pdev);
+}
+EXPORT_SYMBOL(qmp_put);
+
 static int qmp_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -569,6 +614,8 @@ static int qmp_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, qmp);
 
+	atomic_set(&qmp->orphan, 0);
+
 	return 0;
 
 err_remove_qdss_clk:
@@ -590,6 +637,7 @@ static int qmp_remove(struct platform_device *pdev)
 	qmp_cooling_devices_remove(qmp);
 
 	qmp_close(qmp);
+	atomic_set(&qmp->orphan, 1);
 	mbox_free_channel(qmp->mbox_chan);
 
 	return 0;
diff --git a/include/linux/soc/qcom/qcom_aoss.h b/include/linux/soc/qcom/qcom_aoss.h
new file mode 100644
index 0000000..27d00f7
--- /dev/null
+++ b/include/linux/soc/qcom/qcom_aoss.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef __QCOM_AOSS_H__
+#define __QCOM_AOSS_H__
+
+#include <linux/err.h>
+#include <linux/device.h>
+
+struct qmp;
+
+#if IS_ENABLED(CONFIG_QCOM_AOSS_QMP)
+
+int qmp_send(struct qmp *qmp, const void *data, size_t len);
+struct qmp *qmp_get(struct device *dev);
+
+#else
+
+static inline int qmp_send(struct qmp *qmp, const void *data, size_t len)
+{
+	return -ENODEV;
+}
+
+static inline struct qmp *qmp_get(struct device *dev)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+#endif
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V2 2/2] soc: qcom: aoss: Add debugfs entry

[Deepak Kumar Singh]

It can be useful to control the different power states of various
parts of hardware for device testing. Add a debugfs node for qmp so
messages can be sent to aoss for debugging and testing purposes.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
---
 drivers/soc/qcom/qcom_aoss.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index 0e397a7..6057bbe 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -4,6 +4,7 @@
  */
 #include <dt-bindings/power/qcom-aoss-qmp.h>
 #include <linux/clk-provider.h>
+#include <linux/debugfs.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/mailbox_client.h>
@@ -88,6 +89,9 @@ struct qmp {
 	struct clk_hw qdss_clk;
 	struct genpd_onecell_data pd_data;
 	struct qmp_cooling_device *cooling_devs;
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+	struct dentry *debugfs_file;
+#endif /* CONFIG_DEBUG_FS */
 };
 
 struct qmp_pd {
@@ -560,6 +564,34 @@ void qmp_put(struct platform_device *pdev)
 }
 EXPORT_SYMBOL(qmp_put);
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+static ssize_t aoss_dbg_write(struct file *file, const char __user *userstr,
+			      size_t len, loff_t *pos)
+{
+	struct qmp *qmp = file->private_data;
+	char buf[QMP_MSG_LEN] = {};
+	int ret;
+
+	if (!len || len >= QMP_MSG_LEN)
+		return -EINVAL;
+
+	ret  = copy_from_user(buf, userstr, len);
+	if (ret) {
+		dev_err(qmp->dev, "copy from user failed, ret:%d\n", ret);
+		return -EFAULT;
+	}
+
+	ret = qmp_send(qmp, buf, QMP_MSG_LEN);
+
+	return ret ? ret : len;
+}
+
+static const struct file_operations aoss_dbg_fops = {
+	.open = simple_open,
+	.write = aoss_dbg_write,
+};
+#endif /* CONFIG_DEBUG_FS */
+
 static int qmp_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -616,6 +648,11 @@ static int qmp_probe(struct platform_device *pdev)
 
 	atomic_set(&qmp->orphan, 0);
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+	qmp->debugfs_file = debugfs_create_file("aoss_send_message", 0220, NULL,
+						qmp, &aoss_dbg_fops);
+#endif /* CONFIG_DEBUG_FS */
+
 	return 0;
 
 err_remove_qdss_clk:
@@ -632,6 +669,10 @@ static int qmp_remove(struct platform_device *pdev)
 {
 	struct qmp *qmp = platform_get_drvdata(pdev);
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+	debugfs_remove(qmp->debugfs_file);
+#endif /* CONFIG_DEBUG_FS */
+
 	qmp_qdss_clk_remove(qmp);
 	qmp_pd_remove(qmp);
 	qmp_cooling_devices_remove(qmp);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH V2 2/2] soc: qcom: aoss: Add debugfs entry

[Manivannan Sadhasivam]

On Fri, Apr 09, 2021 at 10:09:48AM +0530, Deepak Kumar Singh wrote:
> It can be useful to control the different power states of various
> parts of hardware for device testing. Add a debugfs node for qmp so
> messages can be sent to aoss for debugging and testing purposes.
> 
> Signed-off-by: Chris Lew <clew@codeaurora.org>
> Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
> ---
>  drivers/soc/qcom/qcom_aoss.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
> index 0e397a7..6057bbe 100644
> --- a/drivers/soc/qcom/qcom_aoss.c
> +++ b/drivers/soc/qcom/qcom_aoss.c
> @@ -4,6 +4,7 @@
>   */
>  #include <dt-bindings/power/qcom-aoss-qmp.h>
>  #include <linux/clk-provider.h>
> +#include <linux/debugfs.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/mailbox_client.h>
> @@ -88,6 +89,9 @@ struct qmp {
>  	struct clk_hw qdss_clk;
>  	struct genpd_onecell_data pd_data;
>  	struct qmp_cooling_device *cooling_devs;
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +	struct dentry *debugfs_file;
> +#endif /* CONFIG_DEBUG_FS */
>  };
>  
>  struct qmp_pd {
> @@ -560,6 +564,34 @@ void qmp_put(struct platform_device *pdev)
>  }
>  EXPORT_SYMBOL(qmp_put);
>  
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +static ssize_t aoss_dbg_write(struct file *file, const char __user *userstr,
> +			      size_t len, loff_t *pos)
> +{
> +	struct qmp *qmp = file->private_data;
> +	char buf[QMP_MSG_LEN] = {};
> +	int ret;
> +
> +	if (!len || len >= QMP_MSG_LEN)
> +		return -EINVAL;
> +
> +	ret  = copy_from_user(buf, userstr, len);
> +	if (ret) {
> +		dev_err(qmp->dev, "copy from user failed, ret:%d\n", ret);

Does the userspace need to know how many bytes were not copied? I don't
think this is a useful information. So you could remove this err print.

With that,

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> +		return -EFAULT;
> +	}
> +
> +	ret = qmp_send(qmp, buf, QMP_MSG_LEN);
> +
> +	return ret ? ret : len;
> +}
> +
> +static const struct file_operations aoss_dbg_fops = {
> +	.open = simple_open,
> +	.write = aoss_dbg_write,
> +};
> +#endif /* CONFIG_DEBUG_FS */
> +
>  static int qmp_probe(struct platform_device *pdev)
>  {
>  	struct resource *res;
> @@ -616,6 +648,11 @@ static int qmp_probe(struct platform_device *pdev)
>  
>  	atomic_set(&qmp->orphan, 0);
>  
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +	qmp->debugfs_file = debugfs_create_file("aoss_send_message", 0220, NULL,
> +						qmp, &aoss_dbg_fops);
> +#endif /* CONFIG_DEBUG_FS */
> +
>  	return 0;
>  
>  err_remove_qdss_clk:
> @@ -632,6 +669,10 @@ static int qmp_remove(struct platform_device *pdev)
>  {
>  	struct qmp *qmp = platform_get_drvdata(pdev);
>  
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +	debugfs_remove(qmp->debugfs_file);
> +#endif /* CONFIG_DEBUG_FS */
> +
>  	qmp_qdss_clk_remove(qmp);
>  	qmp_pd_remove(qmp);
>  	qmp_cooling_devices_remove(qmp);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

Re: [PATCH V2 1/2] soc: qcom: aoss: Expose send for generic usecase

[Bjorn Andersson]

On Thu 08 Apr 23:39 CDT 2021, Deepak Kumar Singh wrote:
[..]
> +/**
> + * qmp_get() - get a qmp handle from a device
> + * @dev: client device pointer
> + *
> + * Return: handle to qmp device on success, ERR_PTR() on failure
> + */
> +struct qmp *qmp_get(struct device *dev)
> +{
> +	struct platform_device *pdev;
> +	struct device_node *np;
> +	struct qmp *qmp;
> +
> +	if (!dev || !dev->of_node)
> +		return ERR_PTR(-EINVAL);
> +
> +	np = of_parse_phandle(dev->of_node, "qcom,qmp", 0);
> +	if (!np)
> +		return ERR_PTR(-ENODEV);
> +
> +	pdev = of_find_device_by_node(np);
> +	if (!pdev)
> +		return ERR_PTR(-EINVAL);
> +
> +	qmp = platform_get_drvdata(pdev);
> +	return qmp ? qmp : ERR_PTR(-EPROBE_DEFER);
> +}
> +EXPORT_SYMBOL(qmp_get);
> +
> +void qmp_put(struct platform_device *pdev)
> +{
> +	platform_device_put(pdev);

I was expecting that the devres allocated struct qmp would stick around
until the struct device's release callback came. As described in my
answer to Mani yesterday I was wrong.

As such you need to make sure that struct qmp stays around until
qmp_remove() and all qmp_put() calls has been made.

I presume a reasonable way to achieve this is to not use devm to
allocate our struct qmp, add a kref to the object. So this would have to
be a kref_put() on that instead of the platform_device_put() I asked you
to implement here.

Sorry about that.


The rest of the patch looks good.

Regards,
Bjorn

Re: [PATCH V2 1/2] soc: qcom: aoss: Expose send for generic usecase

[Deepak Kumar Singh]

On 4/14/2021 2:42 AM, Bjorn Andersson wrote:
> On Thu 08 Apr 23:39 CDT 2021, Deepak Kumar Singh wrote:
> [..]
>> +/**
>> + * qmp_get() - get a qmp handle from a device
>> + * @dev: client device pointer
>> + *
>> + * Return: handle to qmp device on success, ERR_PTR() on failure
>> + */
>> +struct qmp *qmp_get(struct device *dev)
>> +{
>> +	struct platform_device *pdev;
>> +	struct device_node *np;
>> +	struct qmp *qmp;
>> +
>> +	if (!dev || !dev->of_node)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	np = of_parse_phandle(dev->of_node, "qcom,qmp", 0);
>> +	if (!np)
>> +		return ERR_PTR(-ENODEV);
>> +
>> +	pdev = of_find_device_by_node(np);
>> +	if (!pdev)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	qmp = platform_get_drvdata(pdev);
>> +	return qmp ? qmp : ERR_PTR(-EPROBE_DEFER);
>> +}
>> +EXPORT_SYMBOL(qmp_get);
>> +
>> +void qmp_put(struct platform_device *pdev)
>> +{
>> +	platform_device_put(pdev);
> I was expecting that the devres allocated struct qmp would stick around
> until the struct device's release callback came. As described in my
> answer to Mani yesterday I was wrong.
>
> As such you need to make sure that struct qmp stays around until
> qmp_remove() and all qmp_put() calls has been made.
>
> I presume a reasonable way to achieve this is to not use devm to
> allocate our struct qmp, add a kref to the object. So this would have to
> be a kref_put() on that instead of the platform_device_put() I asked you
> to implement here.
>
> Sorry about that.
>
>
> The rest of the patch looks good.
>
> Regards,
> Bjorn

Hi Bjorn,

Even if we use kref_put(), would it not require platform_device_put()? 
As per my understanding of_find_device_by_node(np) will increment 
node/pdev kobj refcount which both needs to be decremented.