Re: [PATCH v8 4/4] riscv: dts: thead: Enable LicheePi 4A eMMC and microSD

[Drew Fustini <dfustini@tenstorrent.com>]

On Sat, Mar 02, 2024 at 10:13:55PM +0800, Xi Ruoyao wrote:
> On Wed, 2023-12-06 at 00:09 -0800, Drew Fustini wrote:
> > Add emmc node properties for the eMMC device and add sdio0 node
> > properties for the microSD slot. Set the frequency for the sdhci
> > reference clock.
> 
> Hi Drew,
> 
> I've been using the emmc on LicheePi 4A for a while without any problem,
> but when I try the microSD slot I get:
> 
> [    0.531804] mmc1: SDHCI controller on ffe7090000.mmc [ffe7090000.mmc] using ADMA 64-bit
> [    0.842674] mmc1: Tuning failed, falling back to fixed sampling clock
> [    0.855139] mmc1: tuning execution failed: -5
> [    0.859609] mmc1: error -5 whilst initialising SD card
> [   11.359879] mmc1: Timeout waiting for hardware cmd interrupt.
> [   11.365661] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
> [   11.372105] mmc1: sdhci: Sys addr:  0x00000001 | Version:  0x00000005
> [   11.378547] mmc1: sdhci: Blk size:  0x00007040 | Blk cnt:  0x00000000
> [   11.384989] mmc1: sdhci: Argument:  0x00000000 | Trn mode: 0x00000010
> [   11.391432] mmc1: sdhci: Present:   0x03ff0000 | Host ctl: 0x00000017
> [   11.397873] mmc1: sdhci: Power:     0x0000000f | Blk gap:  0x00000000
> [   11.404312] mmc1: sdhci: Wake-up:   0x00000000 | Clock:    0x0000000f
> [   11.410753] mmc1: sdhci: Timeout:   0x00000004 | Int stat: 0x00000000
> [   11.417192] mmc1: sdhci: Int enab:  0x00000020 | Sig enab: 0x00000020
> [   11.423633] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00000000
> [   11.430073] mmc1: sdhci: Caps:      0x3f69c881 | Caps_1:   0x08008177
> [   11.436513] mmc1: sdhci: Cmd:       0x00000102 | Max curr: 0x00191919
> [   11.442954] mmc1: sdhci: Resp[0]:   0x00000900 | Resp[1]:  0x07725f7f
> [   11.449394] mmc1: sdhci: Resp[2]:   0x32db7900 | Resp[3]:  0x00400e00
> [   11.455835] mmc1: sdhci: Host ctl2: 0x0000300b
> [   11.460280] mmc1: sdhci: ADMA Err:  0x00000000 | ADMA Ptr: 0x0000000000882220
> [   11.467416] mmc1: sdhci: ============================================
> [   11.563828] mmc1: Tuning failed, falling back to fixed sampling clock
> [   11.576053] mmc1: tuning execution failed: -5
> [   11.646438] mmc1: new high speed SDXC card at address aaaa
> [   11.653170] mmcblk1: mmc1:aaaa SR256 238 GiB
> 
> I can write something into the SD card and read it back though.  But
> this makes me reluctant to use the SD card for "some real thing" afraid
> of a data loss.
> 
> The SD card is a SanDisk Extreme Pro 256GB (rated "U3, A2, V30").
> 
> Any idea how to debug this issue further?  (Maybe I should try change
> the SD card first but I'd like to discuss the issue before paying money
> for another card.)

Revy informed me that downclocking from 198 MHz to 100 MHz [1] has been
observed to solve this problem. Could you try the following dts patch?

Also, I have noticed the T-Head's 5.10 vendor kernel does have some
updates in sdhci-of-dwcmshc.c related to tuning. I'll look at porting
those to the upstream driving.

Thanks,
Drew

[1] https://github.com/revyos/thead-kernel/pull/62
[2] https://github.com/revyos/thead-kernel/commit/afef388b8e26f0d77f9d2261b6e57991941a213f#diff-ba729b399f3cb86d6a2503890c3626a6426c1572a54f24cd7ab3337f5fc75674

------ [cut here] --------
From db4d406fc15c76317993a39a72061d3df47e86f0 Mon Sep 17 00:00:00 2001
From: Drew Fustini <dfustini@tenstorrent.com>
Date: Sat, 2 Mar 2024 08:21:50 -0800
Subject: [PATCH] riscv: dts: thead: downgrade microSD to 100 MHz max

Downgrade max freq for microSD controller from 198 MHz to 100 MHz to
avoid timeout errors.

Signed-off-by: Drew Fustini <dfustini@tenstorrent.com>
---
 arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi b/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
index 1365d3a512a3..d6ae671f94a9 100644
--- a/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
+++ b/arch/riscv/boot/dts/thead/th1520-lichee-module-4a.dtsi
@@ -53,6 +53,6 @@ &emmc {

 &sdio0 {
        bus-width = <4>;
-       max-frequency = <198000000>;
+       max-frequency = <100000000>;
        status = "okay";
 };
--
2.34.1