On 09/22/2016 03:55 AM, Prabhakar Kushwaha wrote:
Hi Scott,
Sorry for late reply on this thread
-----Original Message----- From: Scott Wood Sent: Friday, September 09, 2016 7:30 AM To: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com; york sun york.sun@nxp.com; u-boot@lists.denx.de Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
On 09/08/2016 08:46 PM, Prabhakar Kushwaha wrote:
-----Original Message----- From: Scott Wood Sent: Friday, September 09, 2016 6:05 AM To: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com; york sun york.sun@nxp.com; u-boot@lists.denx.de Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
On 09/08/2016 07:05 PM, Prabhakar Kushwaha wrote:
-----Original Message----- From: york sun Sent: Thursday, September 08, 2016 9:22 PM To: Prabhakar Kushwaha prabhakar.kushwaha@nxp.com; u- boot@lists.denx.de; Scott Wood scott.wood@nxp.com Subject: Re: [PATCH] arch: ifc: update the IFC IP input clock
On 09/08/2016 02:33 AM, Prabhakar Kushwaha wrote:
<snip>
>>> 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. >> > arch.lbc_clk is only being used for eLBC for device tree fixup. > And I checked the Linux eLBC driver. Looks like it is not using used. >
If this clock is not used, can we drop it completely?
From my point of view Yes.
Scott, Please advice
Well, there is that patch from Matt Weber that is trying to guess the IFC frequency in order to use NWAIT... Not sure if we'll end up actually using NWAIT
(Prabhakar, can you answer my question of whether
there is a better opcode to use with RNDOUT?) or ever sending a real RNDOUT, or if we'll ever care about these newer NAND chips on eLBC, but if U-Boot is currently writing the clock frequency into the device tree I don't see why we'd rip it out.
IFC frequency means IP clock or IP output clock?
External bus clock. Which is currently being written to the device tree?
If IP clock then other patch for eLBC still valid.
What other patch?
For IFC: Code needs to be added for device tree fixup for PowerPC, ARM SoC. It is missing for now :(
No, we don't want to introduce new clock-frequency fixups. If we need this on IFC we should add a clocks property. But if we already have clock-frequency on eLBC then no reason not to use that if needed.
I am not against keeping " bus-frequency" on eLBC. (U-boot fixup bus-frequency not clock-frequncy)
But the value which is getting assigned to " bus-frequency" is not right. Currently, it is setting SYSCLK/LCRR i.e. output clock where eLBC run at CCB or CCB/2. So, if we want to have " bus-frequency " on eLBC then it needs to be corrected.
If the fixup is not correct then just remove it.
-Scott