[PATCH] clk: rockchip: rk3588: keep the OTP gates shared with the secure world on

[PATCH] clk: rockchip: rk3588: keep the OTP gates shared with the secure world on

[Nikolay Bryskin]

The secure OTP controller (OTPC_S) shares three clock gates in
CRU_CLKGATE_CON18 with the non-secure one: clk_otpc_arb,
clk_otpc_auto_rd_g and clk_otp_phy_g. The kernel treats them as ordinary
gates: clk_otpc_auto_rd_g is disabled as unused at the end of boot, and
the rockchip-otp nvmem driver enables clk_otpc_arb and clk_otp_phy_g
around each read and disables them again afterwards.

Firmware in the secure world (OP-TEE reads its hardware unique key and
the secure boot state from OTPC_S, and programs them) has no way to take
a reference on these clocks. Once Linux has gated them, every secure OTP
access times out, and a normal-world nvmem read on another CPU can gate
them in the middle of a secure access, including a fuse programming
cycle.

Mark the three gates critical so the normal world never turns them off.
They are 24 MHz gates for the OTP block only.

Link: https://github.com/OP-TEE/optee_os/pull/8034
Signed-off-by: Nikolay Bryskin <nbryskin@gmail.com>
---
 drivers/clk/rockchip/clk-rk3588.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/rockchip/clk-rk3588.c b/drivers/clk/rockchip/clk-rk3588.c
index 24baa0ef9bf3..8e0f408fdfad 100644
--- a/drivers/clk/rockchip/clk-rk3588.c
+++ b/drivers/clk/rockchip/clk-rk3588.c
@@ -1158,11 +1158,11 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
 			RK3588_CLKGATE_CON(18), 9, GFLAGS),
 	GATE(CLK_OTPC_NS, "clk_otpc_ns", "xin24m", 0,
 			RK3588_CLKGATE_CON(18), 10, GFLAGS),
-	GATE(CLK_OTPC_ARB, "clk_otpc_arb", "xin24m", 0,
+	GATE(CLK_OTPC_ARB, "clk_otpc_arb", "xin24m", CLK_IS_CRITICAL,
 			RK3588_CLKGATE_CON(18), 11, GFLAGS),
-	GATE(CLK_OTP_PHY_G, "clk_otp_phy_g", "xin24m", 0,
+	GATE(CLK_OTP_PHY_G, "clk_otp_phy_g", "xin24m", CLK_IS_CRITICAL,
 			RK3588_CLKGATE_CON(18), 13, GFLAGS),
-	GATE(CLK_OTPC_AUTO_RD_G, "clk_otpc_auto_rd_g", "xin24m", 0,
+	GATE(CLK_OTPC_AUTO_RD_G, "clk_otpc_auto_rd_g", "xin24m", CLK_IS_CRITICAL,
 			RK3588_CLKGATE_CON(18), 12, GFLAGS),
 
 	GATE(PCLK_SARADC, "pclk_saradc", "pclk_top_root", 0,
-- 
2.56.0

Re: [PATCH] clk: rockchip: rk3588: keep the OTP gates shared with the secure world on

[Chen-Yu Tsai]

On Tue, Oct 27, 2026 at 8:28 AM Nikolay Bryskin <nbryskin@gmail.com> wrote:
>
> The secure OTP controller (OTPC_S) shares three clock gates in
> CRU_CLKGATE_CON18 with the non-secure one: clk_otpc_arb,
> clk_otpc_auto_rd_g and clk_otp_phy_g. The kernel treats them as ordinary
> gates: clk_otpc_auto_rd_g is disabled as unused at the end of boot, and
> the rockchip-otp nvmem driver enables clk_otpc_arb and clk_otp_phy_g
> around each read and disables them again afterwards.
>
> Firmware in the secure world (OP-TEE reads its hardware unique key and
> the secure boot state from OTPC_S, and programs them) has no way to take
> a reference on these clocks. Once Linux has gated them, every secure OTP
> access times out, and a normal-world nvmem read on another CPU can gate
> them in the middle of a secure access, including a fuse programming
> cycle.
>
> Mark the three gates critical so the normal world never turns them off.
> They are 24 MHz gates for the OTP block only.

If OPTEE needs some resources kept online, maybe the OPTEE DT node should
have a reference to them?

Otherwise everyone is just playing whack-a-mole in each separate driver.
And for folks that don't have OPTEE, it's a potential waste of power.


ChenYu

> Link: https://github.com/OP-TEE/optee_os/pull/8034
> Signed-off-by: Nikolay Bryskin <nbryskin@gmail.com>
> ---
>  drivers/clk/rockchip/clk-rk3588.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/rockchip/clk-rk3588.c b/drivers/clk/rockchip/clk-rk3588.c
> index 24baa0ef9bf3..8e0f408fdfad 100644
> --- a/drivers/clk/rockchip/clk-rk3588.c
> +++ b/drivers/clk/rockchip/clk-rk3588.c
> @@ -1158,11 +1158,11 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
>                         RK3588_CLKGATE_CON(18), 9, GFLAGS),
>         GATE(CLK_OTPC_NS, "clk_otpc_ns", "xin24m", 0,
>                         RK3588_CLKGATE_CON(18), 10, GFLAGS),
> -       GATE(CLK_OTPC_ARB, "clk_otpc_arb", "xin24m", 0,
> +       GATE(CLK_OTPC_ARB, "clk_otpc_arb", "xin24m", CLK_IS_CRITICAL,
>                         RK3588_CLKGATE_CON(18), 11, GFLAGS),
> -       GATE(CLK_OTP_PHY_G, "clk_otp_phy_g", "xin24m", 0,
> +       GATE(CLK_OTP_PHY_G, "clk_otp_phy_g", "xin24m", CLK_IS_CRITICAL,
>                         RK3588_CLKGATE_CON(18), 13, GFLAGS),
> -       GATE(CLK_OTPC_AUTO_RD_G, "clk_otpc_auto_rd_g", "xin24m", 0,
> +       GATE(CLK_OTPC_AUTO_RD_G, "clk_otpc_auto_rd_g", "xin24m", CLK_IS_CRITICAL,
>                         RK3588_CLKGATE_CON(18), 12, GFLAGS),
>
>         GATE(PCLK_SARADC, "pclk_saradc", "pclk_top_root", 0,
> --
> 2.56.0
>
>