[PATCH] cmd: boot: Update reset usage message
The commit 573a3811edc8 ("sysreset: psci: support system reset in a generic way with PSCI") has added support for warm reset via PSCI but this hasn't been reflected in usage message and user has to look at the code how to run it. That's why update usage text to make this clear.
Here is full help with updated usage: ZynqMP> help reset reset - Perform RESET of the CPU
Usage: reset - cold boot without level specifier reset -w - warm reset if implemented
Signed-off-by: Michal Simek michal.simek@xilinx.com ---
cmd/boot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/cmd/boot.c b/cmd/boot.c index fab294e622be..be67a5980de3 100644 --- a/cmd/boot.c +++ b/cmd/boot.c @@ -58,7 +58,8 @@ U_BOOT_CMD( U_BOOT_CMD( reset, 2, 0, do_reset, "Perform RESET of the CPU", - "" + "- cold boot without level specifier\n" + "reset -w - warm reset if implemented" );
#ifdef CONFIG_CMD_POWEROFF
Hi Michal,
On Wed, Aug 11, 2021 at 1:04 PM Michal Simek michal.simek@xilinx.com wrote:
The commit 573a3811edc8 ("sysreset: psci: support system reset in a generic way with PSCI") has added support for warm reset via PSCI but this hasn't been reflected in usage message and user has to look at the code how to run it. That's why update usage text to make this clear.
Here is full help with updated usage: ZynqMP> help reset reset - Perform RESET of the CPU
Usage: reset - cold boot without level specifier reset -w - warm reset if implemented
Signed-off-by: Michal Simek michal.simek@xilinx.com
cmd/boot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/cmd/boot.c b/cmd/boot.c index fab294e622be..be67a5980de3 100644 --- a/cmd/boot.c +++ b/cmd/boot.c @@ -58,7 +58,8 @@ U_BOOT_CMD( U_BOOT_CMD( reset, 2, 0, do_reset, "Perform RESET of the CPU",
""
"- cold boot without level specifier\n""reset -w - warm reset if implemented");
#ifdef CONFIG_CMD_POWEROFF
2.32.0
Reviewed-by: Igor Opaniuk igor.opaniuk@foundries.io
Dear Michal,
In message 82e0d7efdbd9f8c62f46c7e1a8913ffa52de5a1e.1628676265.git.michal.simek@xilinx.com you wrote:
The commit 573a3811edc8 ("sysreset: psci: support system reset in a generic way with PSCI") has added support for warm reset via PSCI but this hasn't been reflected in usage message and user has to look at the code how to run it. That's why update usage text to make this clear.
Here is full help with updated usage: ZynqMP> help reset reset - Perform RESET of the CPU
Usage: reset - cold boot without level specifier reset -w - warm reset if implemented
In case of the hard (cold) reset - is it really only a reset of the CPU, or of the whole board hardware?
Best regards,
Wolfgang Denk
On 8/13/21 8:11 AM, Wolfgang Denk wrote:
Dear Michal,
In message 82e0d7efdbd9f8c62f46c7e1a8913ffa52de5a1e.1628676265.git.michal.simek@xilinx.com you wrote:
The commit 573a3811edc8 ("sysreset: psci: support system reset in a generic way with PSCI") has added support for warm reset via PSCI but this hasn't been reflected in usage message and user has to look at the code how to run it. That's why update usage text to make this clear.
Here is full help with updated usage: ZynqMP> help reset reset - Perform RESET of the CPU
Usage: reset - cold boot without level specifier reset -w - warm reset if implemented
In case of the hard (cold) reset - is it really only a reset of the CPU, or of the whole board hardware?
If you look at sysreset headers you will find these levels 11 SYSRESET_WARM, /* Reset CPU, keep GPIOs active */ 12 SYSRESET_COLD, /* Reset CPU and GPIOs */ 13 SYSRESET_POWER, /* Reset PMIC (remove and restore power) */ 14 SYSRESET_POWER_OFF, /* Turn off power */
When you call reset sysreset uclass is calling sysreset_walk which is request to drivers with type passed. I see we have mixed drivers which deals with levels and especially in gpio case it is question how you connect it. I develop this for microblaze where gpio is connected reset logic which is normally only for CPU and subsystem. But in general you can connect whatever you want. It means it doesn't need to be only cpu which is reset. Do you want me to update that line and remove CPU from it?
Thanks, Michal
Dear Michal,
In message 90e6c670-9e11-beb8-bcb5-9d22ba00fd11@xilinx.com you wrote:
In case of the hard (cold) reset - is it really only a reset of the CPU, or of the whole board hardware?
If you look at sysreset headers you will find these levels 11 SYSRESET_WARM, /* Reset CPU, keep GPIOs active */ 12 SYSRESET_COLD, /* Reset CPU and GPIOs */ 13 SYSRESET_POWER, /* Reset PMIC (remove and restore power) */ 14 SYSRESET_POWER_OFF, /* Turn off power */
When you call reset sysreset uclass is calling sysreset_walk which is request to drivers with type passed. I see we have mixed drivers which deals with levels and especially in gpio case it is question how you connect it. I develop this for microblaze where gpio is connected reset logic which is normally only for CPU and subsystem. But in general you can connect whatever you want. It means it doesn't need to be only cpu which is reset.
Thanks a lot for the explanation.
Do you want me to update that line and remove CPU from it?
I don't know :-)
What the "reset" command _should_ do is a hard cold boot including the reset of all peripherals - for example, when booting from SPI NOR flash it is mandatory to reset this flash to make sure the ROM boot loader can actually read it.
I would appreciate if the help message documents what it actually does. Also, what the difference between "cold" and "warm" reset is. My expectation (without knowing any hardware details) would be that a warm reset is just a restart of the already loaded code? Or is it just a reset of the CPU (without external reset)? This might then hang the system if it's attempting to boot from a flash which is in the wrong state.
So my problem with this is primarily that I don't understand what the command really does, and the help command is of no help either.
[And if I understand correctly, this is even board dependent?]
Best regards,
Wolfgang Denk
Hi Wolfgang,
On 8/13/21 8:54 AM, Wolfgang Denk wrote:
Dear Michal,
In message 90e6c670-9e11-beb8-bcb5-9d22ba00fd11@xilinx.com you wrote:
In case of the hard (cold) reset - is it really only a reset of the CPU, or of the whole board hardware?
If you look at sysreset headers you will find these levels 11 SYSRESET_WARM, /* Reset CPU, keep GPIOs active */ 12 SYSRESET_COLD, /* Reset CPU and GPIOs */ 13 SYSRESET_POWER, /* Reset PMIC (remove and restore power) */ 14 SYSRESET_POWER_OFF, /* Turn off power */
When you call reset sysreset uclass is calling sysreset_walk which is request to drivers with type passed. I see we have mixed drivers which deals with levels and especially in gpio case it is question how you connect it. I develop this for microblaze where gpio is connected reset logic which is normally only for CPU and subsystem. But in general you can connect whatever you want. It means it doesn't need to be only cpu which is reset.
Thanks a lot for the explanation.
Do you want me to update that line and remove CPU from it?
I don't know :-)
What the "reset" command _should_ do is a hard cold boot including the reset of all peripherals - for example, when booting from SPI NOR flash it is mandatory to reset this flash to make sure the ROM boot loader can actually read it.
I would appreciate if the help message documents what it actually does. Also, what the difference between "cold" and "warm" reset is. My expectation (without knowing any hardware details) would be that a warm reset is just a restart of the already loaded code? Or is it just a reset of the CPU (without external reset)? This might then hang the system if it's attempting to boot from a flash which is in the wrong state.
So my problem with this is primarily that I don't understand what the command really does, and the help command is of no help either.
[And if I understand correctly, this is even board dependent?]
https://developer.arm.com/documentation/den0022/latest/ DEN0022D_b_Power_State_Coordination_Interface.pdf Where 5.11.1 chapter is saying "This function provides a method for performing a system cold reset. To the caller, the behavior is equivalent to a hardware power-cycle sequence."
And also 5.12.2.1 for SYSTEM_RESET2 5.12.2.1 System Warm reset This reset is selected when reset_type is 0x0 (SYSTEM_WARM_RESET). The function is intended to provide a fast reboot path that guarantees not to reset system main memory. This is defined as volatile memory accessible by cores when executing in the calling operating system. This definition does not extend to caches or to memory-mapped IO. The memory that is to be preserved and not trashed by boot firmware needs to be described by firmware table technologies such as ACPI [6] and Device Tree [7] and does not need to cover all available system main memory.
But they also open vendor-specific resets. It means defining resets is more or less implementation dependent.
Thanks, Michal
st 11. 8. 2021 v 12:04 odesÃlatel Michal Simek michal.simek@xilinx.com napsal:
The commit 573a3811edc8 ("sysreset: psci: support system reset in a generic way with PSCI") has added support for warm reset via PSCI but this hasn't been reflected in usage message and user has to look at the code how to run it. That's why update usage text to make this clear.
Here is full help with updated usage: ZynqMP> help reset reset - Perform RESET of the CPU
Usage: reset - cold boot without level specifier reset -w - warm reset if implemented
Signed-off-by: Michal Simek michal.simek@xilinx.com
cmd/boot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/cmd/boot.c b/cmd/boot.c index fab294e622be..be67a5980de3 100644 --- a/cmd/boot.c +++ b/cmd/boot.c @@ -58,7 +58,8 @@ U_BOOT_CMD( U_BOOT_CMD( reset, 2, 0, do_reset, "Perform RESET of the CPU",
""
"- cold boot without level specifier\n""reset -w - warm reset if implemented");
#ifdef CONFIG_CMD_POWEROFF
2.32.0
Applied.
WD: Feel free to send the patch on the top of this one.
Thanks, Michal
participants (4)
-
Igor Opaniuk -
Michal Simek -
Michal Simek -
Wolfgang Denk