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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Sat, 11 Jan 2020 04:05:20 +0900
Message-ID: <CAK7LNAQOCoJC0RzOhTEofHdR+zU5sQTxV-t4nERBExW1ddW5hw@mail.gmail.com>
Subject: Re: mtd raw nand denali.c broken for Intel/Altera Cyclone V
To:     Tim Sander <tim@krieglstein.org>
Cc:     Vignesh Raghavendra <vigneshr@ti.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Dinh Nguyen <dinguyen@kernel.org>,
        linux-mtd <linux-mtd@lists.infradead.org>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Brian Norris <computersforpeace@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>
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On Sat, Jan 11, 2020 at 1:47 AM Tim Sander <tim@krieglstein.org> wrote:
>
> Hi Masahiro Yamada
>
> Sorry for the large delay. I have seen the patches at
> https://lists.infradead.org/pipermail/linux-mtd/2019-December/092852.html
> Seem to resolve the question about the spare_area_skip_bytes register.
>
> I have now set the register to 2 which seems to be the right choice on an Intel
> SocFPGA. But still i am out of luck trying to boot 5.4.5-rt3 or 5.5-rc5. I get the
> following messages during bootup booting:
> [    1.825590] denali-nand-dt ff900000.nand: timeout while waiting for irq 0x1000
> [    1.832936] denali-nand-dt: probe of ff900000.nand failed with error -5
>
> But the commit c19e31d0a32dd 2017-06-13 22:45:38 predates the 4.19 kernel
> release (Mon Oct 22 07:37:37 2018). So it seems there is not an obvious commit
> which is causing the problem. Looking at the changes it might be that the timing
> calculations in the driver changed which might also lead to a similar error.
>
> I am booting via NFS the bootloader is placed in NOR flash.  The corresponding
> nand dts entry is updated to the new format and looks like this:
>                 nand@ff900000 {
>                         #address-cells = <0x1>;
>                         #size-cells = <0x0>;
>                         compatible = "altr,socfpga-denali-nand";
>                         reg = <0xff900000 0x100000 0xffb80000 0x10000>;
>                         reg-names = "nand_data", "denali_reg";
>                         interrupts = <0x0 0x90 0x4>;
>                         clocks = <0x2d 0x1e 0x2e>;
>                         clock-names = "nand", "nand_x", "ecc";
>                         resets = <0x6 0x24>;
>                         status = "okay";
>                         nand@0 {
>                                 reg = <0x0>;
>                                 #address-cells = <0x1>;
>                                 #size-cells = <0x1>;
>                                 partition@0 {
>                                         label = "work";
>                                         reg = <0x0 0x10000000>;
>                                 };
>                         };
>                 };
>
> The last kernel i am able to boot is 4.19.10. I have tried booting:
> 5.1.21, 5.2.9, 5.3-rc8, 5.4.5-rt3 and 5.5-rc5. They all failed. Unfortunately the
> range is quite large for bisecting the problem. It also occurred to me that
> all the platforms with Intel Cyclone V in mainline are development boards
> which boot from SD-card not exhibiting this problem on their default boot path.


What will happen if you apply all of these:

http://patchwork.ozlabs.org/project/linux-mtd/list/?series=149821

on top of the mainline kernel,
and then, hack denali->clk_rate and denali->clk_x_rate as follows?


-       denali->clk_rate = clk_get_rate(dt->clk);
-       denali->clk_x_rate = clk_get_rate(dt->clk_x);
+       denali->clk_rate = 50000000;
+       denali->clk_x_rate = 200000000;


If it still fails, what about this?

       denali->clk_rate = 0;
       denali->clk_x_rate = 0;


> PS: Here is some snippet from an older mail i didn't sent to the list yet which
> might be superseded by now:
> To get into this matter i started reading the "Intel Cyclone V HPS TRM"
> Section 13-20 Preserving Bad Block Markers:
> "You can configure the NAND flash controller to skip over a specified number of
> bytes when it writes the last sector in a page to the spare area. This option
> write the desired offset to the spare_area_skip_bytes register in the config
> group. For example, if the device page size is 2 KB, and the device
> area, set the spare_area_skip_bytes register to 2. When the flash controller
> writes the last sector of the page that overlaps with the spare area, it
> spare_area_skip_bytes must be an even number. For example, if the bad block
> marker is a single byte, set spare_area_skip_bytes to 2."

I did not know this documentation.

It says "For example" (twice),
it sounds uncertain to me, though.

Anyway, an intel engineer checked the boot ROM code.
SPARE_AREA_SKIP_BYTES=2 is correct, he said.


-- 
Best Regards
Masahiro Yamada