[U-Boot] [PATCH v3] Allow AM335x MPU core clock speed to be specified in the board config file

[U-Boot] [PATCH v3] Allow AM335x MPU core clock speed to be specified in the board config file

[Mark Jackson]

Allow AM335x MPU core clock speed to be specified in the board config file.
To use, add the following to the board's config file:-

#define CONFIG_SYS_MPUCLK	<desired clock freq in Hz>

Signed-off-by: Mark Jackson <mpfj@newflow.co.uk>
---
Changes in v3:
- Changed from V_MPUCLK to CONFIG_SYS_MPUCLK
- Added entry in README

Changes in v2:
- Tweaked after comments from Peter Korsgaard

 README                                           |    4 ++++
 arch/arm/include/asm/arch-am33xx/clocks_am33xx.h |    7 +++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/README b/README
index d8cb394..ddf6df2 100644
--- a/README
+++ b/README
@@ -3820,6 +3820,10 @@ Low Level (hardware related) configuration options:
 		If defined, the x86 reset vector code is included. This is not
 		needed when U-Boot is running from Coreboot.
 
+- CONFIG_SYS_MPUCLK
+		Defines the MPU clock speed (in Hz).
+
+		NOTE : currently only supported on AM335x platforms.
 
 Freescale QE/FMAN Firmware Support:
 -----------------------------------
diff --git a/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h b/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
index d748dd2..5f2939b 100644
--- a/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
+++ b/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
@@ -21,8 +21,11 @@
 
 #define OSC	(V_OSCK/1000000)
 
-/* MAIN PLL Fdll = 550 MHZ, */
-#define MPUPLL_M	550
+/* MAIN PLL Fdll = 550 MHz, by default */
+#ifndef CONFIG_SYS_MPUCLK
+#define CONFIG_SYS_MPUCLK	550000000
+#endif
+#define MPUPLL_M	(CONFIG_SYS_MPUCLK/1000000)
 #define MPUPLL_N	(OSC-1)
 #define MPUPLL_M2	1
 
-- 
1.7.9.5

[U-Boot] [PATCH v3] Allow AM335x MPU core clock speed to be specified in the board config file

[Wolfgang Denk]

Dear Mark Jackson,

In message <51346856.8020504@mimc.co.uk> you wrote:
> Allow AM335x MPU core clock speed to be specified in the board config file.
> To use, add the following to the board's config file:-
> 
> #define CONFIG_SYS_MPUCLK	<desired clock freq in Hz>

Why do you claim an accuracy of Hz here, when in the code you silently
throw away any sub-MHz parts anyway?  Why not leaving it at MHz as it
was before, and as used in the code?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
There are three ways to get something done:
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        (3) Forbid your kids to do it.

[U-Boot] [PATCH v3] Allow AM335x MPU core clock speed to be specified in the board config file

[Mark Jackson]

On 04/03/13 11:14, Wolfgang Denk wrote:
> Dear Mark Jackson,
> 
> In message <51346856.8020504@mimc.co.uk> you wrote:
>> Allow AM335x MPU core clock speed to be specified in the board config file.
>> To use, add the following to the board's config file:-
>>
>> #define CONFIG_SYS_MPUCLK	<desired clock freq in Hz>
> 
> Why do you claim an accuracy of Hz here, when in the code you silently
> throw away any sub-MHz parts anyway?  Why not leaving it at MHz as it
> was before, and as used in the code?

I was simply copying the format of the existing V_OSCK defines, but I'm
happy to change it.

Regards
Mark J.