[U-Boot] [PATCH] README: document the requirements for CONFIG_SYS_HZ
CONFIG_SYS_HZ must be 1000, and get_timer() must therefore return mS. Document this.
Signed-off-by: Stephen Warren swarren@wwwdotorg.org --- README | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/README b/README index 7f2506a..1871ada 100644 --- a/README +++ b/README @@ -495,6 +495,12 @@ The following options need to be configured: exists, unlike the similar options in the Linux kernel. Do not set these options unless they apply!
+- CPU timer options: + CONFIG_SYS_HZ + + The frequency of the timer returned by get_timer(). This value + MUST be 1000. + - Linux Kernel Interface: CONFIG_CLOCKS_IN_MHZ
Dear Stephen,
In message 1363923692-12748-1-git-send-email-swarren@wwwdotorg.org you wrote:
CONFIG_SYS_HZ must be 1000, and get_timer() must therefore return mS. Document this.
"must return mS" ? "mS" means Milli-Siemens, which is a unit of electric conductance and electric admittance. You mean "ms" = milliseconds ...
+- CPU timer options:
CONFIG_SYS_HZThe frequency of the timer returned by get_timer(). This valueMUST be 1000.
This is misleading, or even incorrect. If I read this, I would expect that get_timer() returns 1000. Obviously, this is incorrect. Instead, get_timer() returns timestamp information in millisecond resolution.
Best regards,
Wolfgang Denk
On 03/22/2013 03:12 PM, Wolfgang Denk wrote:
Dear Stephen,
In message 1363923692-12748-1-git-send-email-swarren@wwwdotorg.org you wrote:
CONFIG_SYS_HZ must be 1000, and get_timer() must therefore return mS. Document this.
"must return mS" ? "mS" means Milli-Siemens, which is a unit of electric conductance and electric admittance. You mean "ms" = milliseconds ...
It seems that's true.
+- CPU timer options:
CONFIG_SYS_HZThe frequency of the timer returned by get_timer(). This valueMUST be 1000.This is misleading, or even incorrect. If I read this, I would expect that get_timer() returns 1000. Obviously, this is incorrect. Instead, get_timer() returns timestamp information in millisecond resolution.
That is not what that sentence means.
Dear Stephen Warren,
In message 514CCAAE.6020909@wwwdotorg.org you wrote:
The frequency of the timer returned by get_timer(). This valueMUST be 1000.This is misleading, or even incorrect. If I read this, I would expect that get_timer() returns 1000. Obviously, this is incorrect. Instead, get_timer() returns timestamp information in millisecond resolution.
That is not what that sentence means.
Yes, I know. But it can be easily misinterpreted.
Best regards,
Wolfgang Denk
On Fri, Mar 22, 2013 at 10:41:53PM +0100, Wolfgang Denk wrote:
Dear Stephen Warren,
In message 514CCAAE.6020909@wwwdotorg.org you wrote:
The frequency of the timer returned by get_timer(). This valueMUST be 1000.This is misleading, or even incorrect. If I read this, I would expect that get_timer() returns 1000. Obviously, this is incorrect. Instead, get_timer() returns timestamp information in millisecond resolution.
That is not what that sentence means.
Yes, I know. But it can be easily misinterpreted.
How about: The frequency of the timer returned by get_timer(). get_timer() must operate in milliseconds and this CONFIG option must be set to 1000.
participants (3)
-
Stephen Warren -
Tom Rini -
Wolfgang Denk