From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Chen Date: Tue, 18 May 2021 10:05:11 +0800 Subject: [PATCH] riscv: Split SiFive CLINT support between SPL and U-Boot proper In-Reply-To: <752D002CFF5D0F4FA35C0100F1D73F3FE5EA2FA5@ATCPCS12.andestech.com> References: <20210511120412.25065-1-bmeng.cn@gmail.com> <752D002CFF5D0F4FA35C0100F1D73F3FE5EA2FA5@ATCPCS12.andestech.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de > From: Bin Meng > Sent: Tuesday, May 11, 2021 8:04 PM > To: Rick Jian-Zhi Chen(???) ; Sean Anderson ; u-boot at lists.denx.de > Cc: Anup Patel ; Bin Meng > Subject: [PATCH] riscv: Split SiFive CLINT support between SPL and U-Boot proper > > At present there is only one Kconfig option CONFIG_SIFIVE_CLINT to control the enabling of SiFive CLINT support in both SPL (M-mode) and U-Boot proper (S-mode). So for a typical SPL config that the SiFive CLINT driver is enabled in both SPL and U-Boot proper, that means the S-mode U-Boot tries to access the memory-mapped CLINT registers directly, instead of the normal 'rdtime' instruction. > > This was not a problem before, as the hardware does not forbid the access from S-mode. However this becomes an issue now with OpenSBI commit 8b569803475e ("lib: utils/sys: Add CLINT memregion in the root domain") that the SiFive CLINT register space is protected by PMP for M-mode access only. U-Boot proper does not boot any more with the latest OpenSBI, that access exceptions are fired forever from U-Boot when trying to read the timer value via the SiFive CLINT driver in U-Boot. > > To solve this, we need to split current SiFive CLINT support between SPL and U-Boot proper, using 2 separate Kconfig options. > > Signed-off-by: Bin Meng > --- > > arch/riscv/Kconfig | 9 ++++++++- > arch/riscv/cpu/fu540/Kconfig | 2 +- > arch/riscv/cpu/generic/Kconfig | 3 ++- > arch/riscv/include/asm/global_data.h | 2 +- > arch/riscv/lib/Makefile | 2 +- > drivers/timer/Makefile | 2 +- > 6 files changed, 14 insertions(+), 6 deletions(-) Reviewed-by: Rick Chen