diff mbox series

[v4,4/5] firmware: qcom_scm: Refactor code to support multiple download mode

Message ID 1679935281-18445-5-git-send-email-quic_mojha@quicinc.com
State Superseded
Headers show
Series Refactor to support multiple download mode | expand

Commit Message

Mukesh Ojha March 27, 2023, 4:41 p.m. UTC
Currently on Qualcomm SoC, download_mode is enabled if
CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT is selected.

Refactor the code such that it supports multiple download
modes and drop CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT config
instead, give interface to set the download mode from
module parameter.

Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
---
 drivers/firmware/Kconfig    | 11 ---------
 drivers/firmware/qcom_scm.c | 59 +++++++++++++++++++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 18 deletions(-)

Comments

Bjorn Andersson March 27, 2023, 6:23 p.m. UTC | #1
On Mon, Mar 27, 2023 at 10:11:20PM +0530, Mukesh Ojha wrote:
[..]
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 3c6c5e7..0c94429 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -20,11 +20,11 @@
>  #include <linux/clk.h>
>  #include <linux/reset-controller.h>
>  #include <linux/arm-smccc.h>
> +#include <linux/kstrtox.h>
>  
>  #include "qcom_scm.h"
>  
> -static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
> -module_param(download_mode, bool, 0);
> +static u32 download_mode;
>  
>  #define SCM_HAS_CORE_CLK	BIT(0)
>  #define SCM_HAS_IFACE_CLK	BIT(1)
> @@ -32,6 +32,7 @@ module_param(download_mode, bool, 0);
>  
>  #define QCOM_DOWNLOAD_MODE_MASK 0x30
>  #define QCOM_DOWNLOAD_FULLDUMP	0x1
> +#define QCOM_DOWNLOAD_NODUMP	0x0
>  
>  struct qcom_scm {
>  	struct device *dev;
> @@ -440,8 +441,9 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>  	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>  }
>  
> -static void qcom_scm_set_download_mode(bool enable)
> +static void qcom_scm_set_download_mode(u32 download_mode)
>  {
> +	bool enable = !!download_mode;
>  	bool avail;
>  	int ret = 0;
>  
> @@ -453,7 +455,7 @@ static void qcom_scm_set_download_mode(bool enable)
>  	} else if (__scm->dload_mode_addr) {
>  		ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
>  				QCOM_DOWNLOAD_MODE_MASK,
> -				enable ? QCOM_DOWNLOAD_FULLDUMP : 0);
> +				enable ? download_mode : 0);

Afaict, with QCOM_DOWNLOAD_NODUMP as 0, this says:

  when download_mode is non-zero, write that value, otherwise write 0

That should be the same as "write download_mode", so you should be able
to drop the enable part.

>  	} else {
>  		dev_err(__scm->dev,
>  			"No available mechanism for setting download mode\n");
> @@ -1419,6 +1421,49 @@ static irqreturn_t qcom_scm_irq_handler(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> +
> +static int get_download_mode(char *buffer, const struct kernel_param *kp)
> +{
> +	int len = 0;
> +
> +	if (download_mode == QCOM_DOWNLOAD_FULLDUMP)
> +		len = sysfs_emit(buffer, "full\n");
> +	else if (download_mode == QCOM_DOWNLOAD_NODUMP)
> +		len = sysfs_emit(buffer, "off\n");
> +
> +	return len;
> +}
> +
> +static int set_download_mode(const char *val, const struct kernel_param *kp)
> +{
> +	u32 old = download_mode;
> +
> +	if (!strncmp(val, "full", strlen("full"))) {

strcmp loops over the two string until they differ and/or both are
'\0'.

As such, the only thing you achieve by using strncmp(.., T, strlen(T))
is that the code has to iterate over T twice - and you make the code
harder to read.

> +		download_mode = QCOM_DOWNLOAD_FULLDUMP;
> +	} else if (!strncmp(val, "off", strlen("off"))) {
> +		download_mode = QCOM_DOWNLOAD_NODUMP;
> +	} else if (kstrtouint(val, 0, &download_mode) ||
> +		   !(download_mode == 0 || download_mode == 1)) {
> +		download_mode = old;
> +		pr_err("unknown download mode\n");

This will result in a lone "unknown download mode" line somewhere in the
kernel log, without association to any driver or any indication what the
unknown value was.

  pr_err("qcom_scm: unknown download mode: %s\n", val);

Would give both context and let the reader know right there what value
the code wasn't able to match.

Regards,
Bjorn
Mukesh Ojha March 28, 2023, 8:18 a.m. UTC | #2
On 3/27/2023 11:53 PM, Bjorn Andersson wrote:
> On Mon, Mar 27, 2023 at 10:11:20PM +0530, Mukesh Ojha wrote:
> [..]
>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>> index 3c6c5e7..0c94429 100644
>> --- a/drivers/firmware/qcom_scm.c
>> +++ b/drivers/firmware/qcom_scm.c
>> @@ -20,11 +20,11 @@
>>   #include <linux/clk.h>
>>   #include <linux/reset-controller.h>
>>   #include <linux/arm-smccc.h>
>> +#include <linux/kstrtox.h>
>>   
>>   #include "qcom_scm.h"
>>   
>> -static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
>> -module_param(download_mode, bool, 0);
>> +static u32 download_mode;
>>   
>>   #define SCM_HAS_CORE_CLK	BIT(0)
>>   #define SCM_HAS_IFACE_CLK	BIT(1)
>> @@ -32,6 +32,7 @@ module_param(download_mode, bool, 0);
>>   
>>   #define QCOM_DOWNLOAD_MODE_MASK 0x30
>>   #define QCOM_DOWNLOAD_FULLDUMP	0x1
>> +#define QCOM_DOWNLOAD_NODUMP	0x0
>>   
>>   struct qcom_scm {
>>   	struct device *dev;
>> @@ -440,8 +441,9 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>>   	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>>   }
>>   
>> -static void qcom_scm_set_download_mode(bool enable)
>> +static void qcom_scm_set_download_mode(u32 download_mode)
>>   {
>> +	bool enable = !!download_mode;
>>   	bool avail;
>>   	int ret = 0;
>>   
>> @@ -453,7 +455,7 @@ static void qcom_scm_set_download_mode(bool enable)
>>   	} else if (__scm->dload_mode_addr) {
>>   		ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
>>   				QCOM_DOWNLOAD_MODE_MASK,
>> -				enable ? QCOM_DOWNLOAD_FULLDUMP : 0);
>> +				enable ? download_mode : 0);
> 
> Afaict, with QCOM_DOWNLOAD_NODUMP as 0, this says:
> 
>    when download_mode is non-zero, write that value, otherwise write 0
> 
> That should be the same as "write download_mode", so you should be able
> to drop the enable part.
> 
>>   	} else {
>>   		dev_err(__scm->dev,
>>   			"No available mechanism for setting download mode\n");
>> @@ -1419,6 +1421,49 @@ static irqreturn_t qcom_scm_irq_handler(int irq, void *data)
>>   	return IRQ_HANDLED;
>>   }
>>   
>> +
>> +static int get_download_mode(char *buffer, const struct kernel_param *kp)
>> +{
>> +	int len = 0;
>> +
>> +	if (download_mode == QCOM_DOWNLOAD_FULLDUMP)
>> +		len = sysfs_emit(buffer, "full\n");
>> +	else if (download_mode == QCOM_DOWNLOAD_NODUMP)
>> +		len = sysfs_emit(buffer, "off\n");
>> +
>> +	return len;
>> +}
>> +
>> +static int set_download_mode(const char *val, const struct kernel_param *kp)
>> +{
>> +	u32 old = download_mode;
>> +
>> +	if (!strncmp(val, "full", strlen("full"))) {
> 
> strcmp loops over the two string until they differ and/or both are
> '\0'.
> 
> As such, the only thing you achieve by using strncmp(.., T, strlen(T))
> is that the code has to iterate over T twice - and you make the code
> harder to read.


If we use strcmp, i need to use "full\n" which we would not want to do.
I think, we need to take this hit.

-- Mukesh
> 
>> +		download_mode = QCOM_DOWNLOAD_FULLDUMP;
>> +	} else if (!strncmp(val, "off", strlen("off"))) {
>> +		download_mode = QCOM_DOWNLOAD_NODUMP;
>> +	} else if (kstrtouint(val, 0, &download_mode) ||
>> +		   !(download_mode == 0 || download_mode == 1)) {
>> +		download_mode = old;
>> +		pr_err("unknown download mode\n");
> 
> This will result in a lone "unknown download mode" line somewhere in the
> kernel log, without association to any driver or any indication what the
> unknown value was.
> 
>    pr_err("qcom_scm: unknown download mode: %s\n", val);
> 
> Would give both context and let the reader know right there what value
> the code wasn't able to match.
> 
> Regards,
> Bjorn
Dmitry Baryshkov March 28, 2023, 10:14 p.m. UTC | #3
On 28/03/2023 11:18, Mukesh Ojha wrote:
> 
> 
> On 3/27/2023 11:53 PM, Bjorn Andersson wrote:
>> On Mon, Mar 27, 2023 at 10:11:20PM +0530, Mukesh Ojha wrote:
>> [..]
>>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>>> index 3c6c5e7..0c94429 100644
>>> --- a/drivers/firmware/qcom_scm.c
>>> +++ b/drivers/firmware/qcom_scm.c
>>> @@ -20,11 +20,11 @@
>>>   #include <linux/clk.h>
>>>   #include <linux/reset-controller.h>
>>>   #include <linux/arm-smccc.h>
>>> +#include <linux/kstrtox.h>
>>>   #include "qcom_scm.h"
>>> -static bool download_mode = 
>>> IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
>>> -module_param(download_mode, bool, 0);
>>> +static u32 download_mode;
>>>   #define SCM_HAS_CORE_CLK    BIT(0)
>>>   #define SCM_HAS_IFACE_CLK    BIT(1)
>>> @@ -32,6 +32,7 @@ module_param(download_mode, bool, 0);
>>>   #define QCOM_DOWNLOAD_MODE_MASK 0x30
>>>   #define QCOM_DOWNLOAD_FULLDUMP    0x1
>>> +#define QCOM_DOWNLOAD_NODUMP    0x0
>>>   struct qcom_scm {
>>>       struct device *dev;
>>> @@ -440,8 +441,9 @@ static int __qcom_scm_set_dload_mode(struct 
>>> device *dev, bool enable)
>>>       return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>>>   }
>>> -static void qcom_scm_set_download_mode(bool enable)
>>> +static void qcom_scm_set_download_mode(u32 download_mode)
>>>   {
>>> +    bool enable = !!download_mode;
>>>       bool avail;
>>>       int ret = 0;
>>> @@ -453,7 +455,7 @@ static void qcom_scm_set_download_mode(bool enable)
>>>       } else if (__scm->dload_mode_addr) {
>>>           ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
>>>                   QCOM_DOWNLOAD_MODE_MASK,
>>> -                enable ? QCOM_DOWNLOAD_FULLDUMP : 0);
>>> +                enable ? download_mode : 0);
>>
>> Afaict, with QCOM_DOWNLOAD_NODUMP as 0, this says:
>>
>>    when download_mode is non-zero, write that value, otherwise write 0
>>
>> That should be the same as "write download_mode", so you should be able
>> to drop the enable part.
>>
>>>       } else {
>>>           dev_err(__scm->dev,
>>>               "No available mechanism for setting download mode\n");
>>> @@ -1419,6 +1421,49 @@ static irqreturn_t qcom_scm_irq_handler(int 
>>> irq, void *data)
>>>       return IRQ_HANDLED;
>>>   }
>>> +
>>> +static int get_download_mode(char *buffer, const struct kernel_param 
>>> *kp)
>>> +{
>>> +    int len = 0;
>>> +
>>> +    if (download_mode == QCOM_DOWNLOAD_FULLDUMP)
>>> +        len = sysfs_emit(buffer, "full\n");
>>> +    else if (download_mode == QCOM_DOWNLOAD_NODUMP)
>>> +        len = sysfs_emit(buffer, "off\n");
>>> +
>>> +    return len;
>>> +}
>>> +
>>> +static int set_download_mode(const char *val, const struct 
>>> kernel_param *kp)
>>> +{
>>> +    u32 old = download_mode;
>>> +
>>> +    if (!strncmp(val, "full", strlen("full"))) {
>>
>> strcmp loops over the two string until they differ and/or both are
>> '\0'.
>>
>> As such, the only thing you achieve by using strncmp(.., T, strlen(T))
>> is that the code has to iterate over T twice - and you make the code
>> harder to read.
> 
> 
> If we use strcmp, i need to use "full\n" which we would not want to do.
> I think, we need to take this hit.

There is a special helper for the sysfs files. See sysfs_streq().

> 
> -- Mukesh
>>
>>> +        download_mode = QCOM_DOWNLOAD_FULLDUMP;
>>> +    } else if (!strncmp(val, "off", strlen("off"))) {
>>> +        download_mode = QCOM_DOWNLOAD_NODUMP;
>>> +    } else if (kstrtouint(val, 0, &download_mode) ||
>>> +           !(download_mode == 0 || download_mode == 1)) {
>>> +        download_mode = old;
>>> +        pr_err("unknown download mode\n");
>>
>> This will result in a lone "unknown download mode" line somewhere in the
>> kernel log, without association to any driver or any indication what the
>> unknown value was.
>>
>>    pr_err("qcom_scm: unknown download mode: %s\n", val);
>>
>> Would give both context and let the reader know right there what value
>> the code wasn't able to match.
>>
>> Regards,
>> Bjorn
Mukesh Ojha March 29, 2023, 7:33 a.m. UTC | #4
On 3/29/2023 3:44 AM, Dmitry Baryshkov wrote:
> On 28/03/2023 11:18, Mukesh Ojha wrote:
>>
>>
>> On 3/27/2023 11:53 PM, Bjorn Andersson wrote:
>>> On Mon, Mar 27, 2023 at 10:11:20PM +0530, Mukesh Ojha wrote:
>>> [..]
>>>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>>>> index 3c6c5e7..0c94429 100644
>>>> --- a/drivers/firmware/qcom_scm.c
>>>> +++ b/drivers/firmware/qcom_scm.c
>>>> @@ -20,11 +20,11 @@
>>>>   #include <linux/clk.h>
>>>>   #include <linux/reset-controller.h>
>>>>   #include <linux/arm-smccc.h>
>>>> +#include <linux/kstrtox.h>
>>>>   #include "qcom_scm.h"
>>>> -static bool download_mode = 
>>>> IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
>>>> -module_param(download_mode, bool, 0);
>>>> +static u32 download_mode;
>>>>   #define SCM_HAS_CORE_CLK    BIT(0)
>>>>   #define SCM_HAS_IFACE_CLK    BIT(1)
>>>> @@ -32,6 +32,7 @@ module_param(download_mode, bool, 0);
>>>>   #define QCOM_DOWNLOAD_MODE_MASK 0x30
>>>>   #define QCOM_DOWNLOAD_FULLDUMP    0x1
>>>> +#define QCOM_DOWNLOAD_NODUMP    0x0
>>>>   struct qcom_scm {
>>>>       struct device *dev;
>>>> @@ -440,8 +441,9 @@ static int __qcom_scm_set_dload_mode(struct 
>>>> device *dev, bool enable)
>>>>       return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>>>>   }
>>>> -static void qcom_scm_set_download_mode(bool enable)
>>>> +static void qcom_scm_set_download_mode(u32 download_mode)
>>>>   {
>>>> +    bool enable = !!download_mode;
>>>>       bool avail;
>>>>       int ret = 0;
>>>> @@ -453,7 +455,7 @@ static void qcom_scm_set_download_mode(bool enable)
>>>>       } else if (__scm->dload_mode_addr) {
>>>>           ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
>>>>                   QCOM_DOWNLOAD_MODE_MASK,
>>>> -                enable ? QCOM_DOWNLOAD_FULLDUMP : 0);
>>>> +                enable ? download_mode : 0);
>>>
>>> Afaict, with QCOM_DOWNLOAD_NODUMP as 0, this says:
>>>
>>>    when download_mode is non-zero, write that value, otherwise write 0
>>>
>>> That should be the same as "write download_mode", so you should be able
>>> to drop the enable part.
>>>
>>>>       } else {
>>>>           dev_err(__scm->dev,
>>>>               "No available mechanism for setting download mode\n");
>>>> @@ -1419,6 +1421,49 @@ static irqreturn_t qcom_scm_irq_handler(int 
>>>> irq, void *data)
>>>>       return IRQ_HANDLED;
>>>>   }
>>>> +
>>>> +static int get_download_mode(char *buffer, const struct 
>>>> kernel_param *kp)
>>>> +{
>>>> +    int len = 0;
>>>> +
>>>> +    if (download_mode == QCOM_DOWNLOAD_FULLDUMP)
>>>> +        len = sysfs_emit(buffer, "full\n");
>>>> +    else if (download_mode == QCOM_DOWNLOAD_NODUMP)
>>>> +        len = sysfs_emit(buffer, "off\n");
>>>> +
>>>> +    return len;
>>>> +}
>>>> +
>>>> +static int set_download_mode(const char *val, const struct 
>>>> kernel_param *kp)
>>>> +{
>>>> +    u32 old = download_mode;
>>>> +
>>>> +    if (!strncmp(val, "full", strlen("full"))) {
>>>
>>> strcmp loops over the two string until they differ and/or both are
>>> '\0'.
>>>
>>> As such, the only thing you achieve by using strncmp(.., T, strlen(T))
>>> is that the code has to iterate over T twice - and you make the code
>>> harder to read.
>>
>>
>> If we use strcmp, i need to use "full\n" which we would not want to do.
>> I think, we need to take this hit.
> 
> There is a special helper for the sysfs files. See sysfs_streq().

You are awesome !!
Thanks.

Have applied the change.

-- Mukesh
> 
>>
>> -- Mukesh
>>>
>>>> +        download_mode = QCOM_DOWNLOAD_FULLDUMP;
>>>> +    } else if (!strncmp(val, "off", strlen("off"))) {
>>>> +        download_mode = QCOM_DOWNLOAD_NODUMP;
>>>> +    } else if (kstrtouint(val, 0, &download_mode) ||
>>>> +           !(download_mode == 0 || download_mode == 1)) {
>>>> +        download_mode = old;
>>>> +        pr_err("unknown download mode\n");
>>>
>>> This will result in a lone "unknown download mode" line somewhere in the
>>> kernel log, without association to any driver or any indication what the
>>> unknown value was.
>>>
>>>    pr_err("qcom_scm: unknown download mode: %s\n", val);
>>>
>>> Would give both context and let the reader know right there what value
>>> the code wasn't able to match.
>>>
>>> Regards,
>>> Bjorn
>
diff mbox series

Patch

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index b59e304..ff7e9f3 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -215,17 +215,6 @@  config MTK_ADSP_IPC
 config QCOM_SCM
 	tristate
 
-config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
-	bool "Qualcomm download mode enabled by default"
-	depends on QCOM_SCM
-	help
-	  A device with "download mode" enabled will upon an unexpected
-	  warm-restart enter a special debug mode that allows the user to
-	  "download" memory content over USB for offline postmortem analysis.
-	  The feature can be enabled/disabled on the kernel command line.
-
-	  Say Y here to enable "download mode" by default.
-
 config SYSFB
 	bool
 	select BOOT_VESA_SUPPORT
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 3c6c5e7..0c94429 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -20,11 +20,11 @@ 
 #include <linux/clk.h>
 #include <linux/reset-controller.h>
 #include <linux/arm-smccc.h>
+#include <linux/kstrtox.h>
 
 #include "qcom_scm.h"
 
-static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
-module_param(download_mode, bool, 0);
+static u32 download_mode;
 
 #define SCM_HAS_CORE_CLK	BIT(0)
 #define SCM_HAS_IFACE_CLK	BIT(1)
@@ -32,6 +32,7 @@  module_param(download_mode, bool, 0);
 
 #define QCOM_DOWNLOAD_MODE_MASK 0x30
 #define QCOM_DOWNLOAD_FULLDUMP	0x1
+#define QCOM_DOWNLOAD_NODUMP	0x0
 
 struct qcom_scm {
 	struct device *dev;
@@ -440,8 +441,9 @@  static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
 }
 
-static void qcom_scm_set_download_mode(bool enable)
+static void qcom_scm_set_download_mode(u32 download_mode)
 {
+	bool enable = !!download_mode;
 	bool avail;
 	int ret = 0;
 
@@ -453,7 +455,7 @@  static void qcom_scm_set_download_mode(bool enable)
 	} else if (__scm->dload_mode_addr) {
 		ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
 				QCOM_DOWNLOAD_MODE_MASK,
-				enable ? QCOM_DOWNLOAD_FULLDUMP : 0);
+				enable ? download_mode : 0);
 	} else {
 		dev_err(__scm->dev,
 			"No available mechanism for setting download mode\n");
@@ -1419,6 +1421,49 @@  static irqreturn_t qcom_scm_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+
+static int get_download_mode(char *buffer, const struct kernel_param *kp)
+{
+	int len = 0;
+
+	if (download_mode == QCOM_DOWNLOAD_FULLDUMP)
+		len = sysfs_emit(buffer, "full\n");
+	else if (download_mode == QCOM_DOWNLOAD_NODUMP)
+		len = sysfs_emit(buffer, "off\n");
+
+	return len;
+}
+
+static int set_download_mode(const char *val, const struct kernel_param *kp)
+{
+	u32 old = download_mode;
+
+	if (!strncmp(val, "full", strlen("full"))) {
+		download_mode = QCOM_DOWNLOAD_FULLDUMP;
+	} else if (!strncmp(val, "off", strlen("off"))) {
+		download_mode = QCOM_DOWNLOAD_NODUMP;
+	} else if (kstrtouint(val, 0, &download_mode) ||
+		   !(download_mode == 0 || download_mode == 1)) {
+		download_mode = old;
+		pr_err("unknown download mode\n");
+		return -EINVAL;
+	}
+
+	if (__scm)
+		qcom_scm_set_download_mode(download_mode);
+
+	return 0;
+}
+
+static const struct kernel_param_ops download_mode_param_ops = {
+	.get = get_download_mode,
+	.set = set_download_mode,
+};
+
+module_param_cb(download_mode, &download_mode_param_ops, NULL, 0644);
+MODULE_PARM_DESC(download_mode,
+		 "Download mode: off/full or 0/1 for existing users");
+
 static int qcom_scm_probe(struct platform_device *pdev)
 {
 	struct qcom_scm *scm;
@@ -1512,12 +1557,12 @@  static int qcom_scm_probe(struct platform_device *pdev)
 	__get_convention();
 
 	/*
-	 * If requested enable "download mode", from this point on warmboot
+	 * If "download mode" is requested, from this point on warmboot
 	 * will cause the boot stages to enter download mode, unless
 	 * disabled below by a clean shutdown/reboot.
 	 */
 	if (download_mode)
-		qcom_scm_set_download_mode(true);
+		qcom_scm_set_download_mode(download_mode);
 
 	return 0;
 }
@@ -1525,7 +1570,7 @@  static int qcom_scm_probe(struct platform_device *pdev)
 static void qcom_scm_shutdown(struct platform_device *pdev)
 {
 	/* Clean shutdown, disable download mode to allow normal restart */
-	qcom_scm_set_download_mode(false);
+	qcom_scm_set_download_mode(QCOM_DOWNLOAD_NODUMP);
 }
 
 static const struct of_device_id qcom_scm_dt_match[] = {