From: Sam Edwards cfsworks@gmail.com
stable inclusion from stable-v6.6.7 commit 92f095553ae58733962aa5ef5ba9882bda105b06 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8SSQ4
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 37f3d6108730713c411827ab4af764909f4dfc78 ]
JEDEC standard JESD84-B51 defines the eMMC Data Strobe line, which is currently used only in HS400 mode, as a device->host clock signal that "is used only in read operation. The Data Strobe is always High-Z (not driven by the device and pulled down by RDS) or Driven Low in write operation, except during CRC status response." RDS is a pull-down resistor specified in the 10K-100K ohm range. Thus per the standard, the Data Strobe is always pulled to ground (by the eMMC and/or RDS) during write operations.
Evidently, the eMMC host controller in the RK3588 considers an active voltage on the eMMC-DS line during a write to be an error.
The default (i.e. hardware reset, and Rockchip BSP) behavior for the RK3588 is to activate the eMMC-DS pin's builtin pull-down. As a result, many RK3588 board designers do not bother adding a dedicated RDS resistor, instead relying on the RK3588's internal bias. The current devicetree, however, disables this bias (`pcfg_pull_none`), breaking HS400-mode writes for boards without a dedicated RDS, but with an eMMC chip that chooses to High-Z (instead of drive-low) the eMMC-DS line. (The Turing RK1 is one such board.)
Fix this by changing the bias in the (common) emmc_data_strobe case to reflect the expected hardware/BSP behavior. This is unlikely to cause regressions elsewhere: the pull-down is only relevant for High-Z eMMCs, and if this is redundant with a (dedicated) RDS resistor, the effective result is only a lower resistance to ground -- where the range of tolerance is quite high. If it does, it's better fixed in the specific devicetrees.
Fixes: d85f8a5c798d5 ("arm64: dts: rockchip: Add rk3588 pinctrl data") Signed-off-by: Sam Edwards CFSworks@gmail.com Link: https://lore.kernel.org/r/20231205202900.4617-2-CFSworks@gmail.com Signed-off-by: Heiko Stuebner heiko@sntech.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi b/arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi index 48181671eacb..0933652bafc3 100644 --- a/arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi +++ b/arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi @@ -369,7 +369,7 @@ emmc_data_strobe: emmc-data-strobe { rockchip,pins = /* emmc_data_strobe */ - <2 RK_PA2 1 &pcfg_pull_none>; + <2 RK_PA2 1 &pcfg_pull_down>; }; };