On 09/07/2016 06:30 PM, Prabhakar Kushwaha wrote:
-----Original Message----- From: york sun Sent: Wednesday, September 07, 2016 9:17 PM To: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com; u- boot@lists.denx.de Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
On 09/06/2016 07:42 PM, Prabhakar Kushwaha wrote:
-----Original Message----- From: york sun Sent: Tuesday, September 06, 2016 9:10 PM To: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com; u- boot@lists.denx.de Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
On 09/06/2016 04:15 AM, Prabhakar Kushwaha wrote:
IFC IP clock is always a constant divisor of platform clock pre-defined per SoC. Clock Control register (CCR) used in current implementation governs IFC IP output clock.
So update IFC IP clock to be defined as per predefined clock divisor of platform clock.
Signed-off-by: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com
README | 3 +++ arch/arm/cpu/armv7/ls102xa/clock.c | 10 ++-------- arch/arm/cpu/armv8/fsl-layerscape/fsl_lsch2_speed.c | 10 ++-------- arch/arm/cpu/armv8/fsl-layerscape/fsl_lsch3_speed.c | 10 ++-------- arch/arm/include/asm/arch-fsl-layerscape/config.h | 3 +++ arch/arm/include/asm/arch-ls102xa/config.h | 1 + arch/powerpc/cpu/mpc85xx/speed.c | 10 ++-------- arch/powerpc/include/asm/config_mpc85xx.h | 9 +++++++++ 8 files changed, 24 insertions(+), 32 deletions(-)
Prabkahar,
Two concerns here
1, it is not only IFC for powerpc. Older SoCs have local bus. That's why the variable is named freq_localbus..
As per my understanding, Issue is valid for eLBC SoC also. Just wanted to confirm from internal IP team before spinning patch to fix it.
2, what's the reason for this change? Is it wrong to use ccr to calculate the clock? Or is it because recent Layerscape SoCs have platform PLL different from platform clock? If the latter, can we limit the fix to platform clock and not changing powerpc?
CCR governs the IFC output clock. This clock is used for synchronous NOR, NAND flashes. It is nowhere govern
IFC IP internal clock.
It is true since conception of IFC. Unfortunately code written is wrong since
P1010.
It is confusing everyone.
Are you saying the freq_localbus should be the internal clock, not output clock? As far as I can remember, this variable has always be used for output clock since 85xx. I am open to the idea to change to internal clock only if it makes sense. Browsing the code, I see this variable is used for information only, except for setting arch.lbc_clk.
Everyone believe it to be IFC internal clock not the output clock.
Not everyone.
As I always used to get query from customers about wrong IFC speed.
So better to print IP clock to avoid any confusion. IFC output clock will be printed when it is actually being used during synchronous NOR, syn NAND.
I am not against changing it to internal clock. But what are you going to print on the console? I think it is confusing to say IFC or local bus internal clock speed. Please also check how this clock is used and make sure arch.lbc_clk is still correct, after passing to Linux.
York