GPMC in device tree

[Ran Shalit]

On Thu, Aug 6, 2015 at 6:07 AM, Scott Wood <scottwood at freescale.com> wrote:
> On Wed, 2015-08-05 at 17:27 +0300, Ran Shalit wrote:
>> On Wed, Aug 5, 2015 at 9:11 AM, Ran Shalit <ranshalit at gmail.com> wrote:
>> > On Wed, Aug 5, 2015 at 6:56 AM, Ran Shalit <ranshalit at gmail.com> wrote:
>> > > On Wed, Aug 5, 2015 at 12:25 AM, Scott Wood <scottwood at freescale.com>
>> > > wrote:
>> > > > On Wed, 2015-08-05 at 00:22 +0300, Ran Shalit wrote:
>> > > > > On more thing, if I may.
>> > > > > The localbus is also connected to nvram & cpld.
>> > > > > I've noticed that read/write works well, even though I didn't define
>> > > > > anything in device tree.
>> > > > > Is there any reasom to add these devices into device tree, or can we
>> > > > > use the cpld and nvram without the definition in device tree ?
>> > > >
>> > > > I don't know what you're doing in your kernel to access devices that
>> > > > aren't
>> > > > in the device tree.  You should add the devices to the device tree,
>> > > > and have
>> > > > the kernel use it rather than hardcoded info.
>> > > >
>> > > > -Scott
>> > > >
>> > > Hi,
>> > >
>> > > Yes I understand.
>> > > But It is worse noting that I have no localbus entry in the device tree.
>> > > Yes, The nvram, cpld which are both connected to device tree, seems to
>> > > work without any issues.
>> > >
>> > > Thanks,
>> > > Ran
>> >
>> > I apologyze for the bad english, I meant "it worth to note" that there
>> > is no localbus entry at all in the device tree.
>> > So I wander how the nvram and cpld worked...
>
> I don't know how it worked -- presumably there's something in your kernel
> that hardcodes knowledge of those devices.
>
>> > If I may please ask, what should be the "compatible" for generic
>> > devices such as  nvram/cpld ?
>
> CPLD is not a generic device.  The compatible should describe the logic that
> has been programmed into the CPLD.
>
>> > I assume that if they worked without any entry, it means that there is
>> > no need for specific driver.
>> >
>> > Regards,
>> > Ran
>>
>> Hi,
>>
>> After studing the localbus configuration as should be configured in
>> device tree for powerpc, I think I have come with the following
>> configuration, (not yet tested on board):
>>
>>
>>  localbus at e0005000{
>> #address-cells = <2>;
>> #size-cells = <1>;
>>     compatible = "fsl,mpc8349-localbus", "simple-bus";
>>      reg = <0xe0005000 0x1000>;
>>      interrupts = <77 0x8>;
>>      interrupt-parent = <&ipic>;
>>
>>
>> /* NOR and NAND Flashes */
>>    ranges = <0x0 0x0 0xff800000 0x00800000         /* 8MB NOR Flash */
>>              0x1 0x0 0xF8000000 0x08000000      /* User flash (same
>> nor, in burst mode) 128M */
>>              0x2 0x0 0xf7e00000 0x00200000>;    /*NVRAM/CPLD C2 is
>> selected in CPLD , */
>> /*nvram 0xf7e00000 1MB */
>> /*cpld      0xf7f00000 1M  (<- different address!)*/
>> nor at 0,0 {
>> #address-cells = <1>;
>> #size-cells = <1>;
>> compatible = "cfi-flash";
>> reg = <0x0 0x0 0x1000000>;
>> #bank-width = <1>;
>> device-width = <4>;
>>
>> };
>> };
>

Hi ,

I reboot the board, with the new device tree localbus, but I don't
have any new /dev/mtdX entry for the NOR flash.
There is no HW issue, becuase we can R/W access the NOR flash from u-boot.
Is there any hint what can be the issue here ? I've checked in kernel
config and validated that mtd is supported.
The NOR flash is S29GL512P , SPANSION.

localbus at e0005000 {
#address-cells = <2>;
#size-cells = <1>;
   compatible = "fsl,mpc8349-localbus", "simple-bus";
    reg = <0xe0005000 0x1000>;
    interrupts = <77 0x8>;
    interrupt-parent = <&ipic>;


# NOR and NAND Flashes
  ranges = <0x0 0x0 0xff800000 0x00800000
    0x1 0x0 0xF8000000 0x08000000
    0x2 0x0 0xf7e00000 0x00200000>;
nor at 0,0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "cfi-flash";
reg = <0x0 0x0 0x00800000>;
#bank-width = <1>;
device-width = <1>;

};
};

Best Regards,
Ran