On 5/11/21 8:04 AM, Bin Meng wrote:
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 <bmeng...@gmail.com>
---

  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(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 3f221dccdb..82e10da11e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -158,7 +158,14 @@ config DMA_ADDR_T_64BIT
config SIFIVE_CLINT
        bool
-       depends on RISCV_MMODE || SPL_RISCV_MMODE
+       depends on RISCV_MMODE
+       help
+         The SiFive CLINT block holds memory-mapped control and status 
registers
+         associated with software and timer interrupts.
+
+config SPL_SIFIVE_CLINT
+       bool
+       depends on SPL_RISCV_MMODE
        help
          The SiFive CLINT block holds memory-mapped control and status 
registers
          associated with software and timer interrupts.
diff --git a/arch/riscv/cpu/fu540/Kconfig b/arch/riscv/cpu/fu540/Kconfig
index 616b25650f..dcf099447b 100644
--- a/arch/riscv/cpu/fu540/Kconfig
+++ b/arch/riscv/cpu/fu540/Kconfig
@@ -11,7 +11,7 @@ config SIFIVE_FU540
        imply CPU
        imply CPU_RISCV
        imply RISCV_TIMER if (RISCV_SMODE || SPL_RISCV_SMODE)
-       imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
+       imply SPL_SIFIVE_CLINT
        imply CMD_CPU
        imply SPL_CPU
        imply SPL_OPENSBI
diff --git a/arch/riscv/cpu/generic/Kconfig b/arch/riscv/cpu/generic/Kconfig
index a4934bb957..e025134b23 100644
--- a/arch/riscv/cpu/generic/Kconfig
+++ b/arch/riscv/cpu/generic/Kconfig
@@ -9,7 +9,8 @@ config GENERIC_RISCV
        imply CPU
        imply CPU_RISCV
        imply RISCV_TIMER if (RISCV_SMODE || SPL_RISCV_SMODE)
-       imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
+       imply SIFIVE_CLINT if RISCV_MMODE
+       imply SPL_SIFIVE_CLINT if SPL_RISCV_MMODE
        imply CMD_CPU
        imply SPL_CPU
        imply SPL_OPENSBI
diff --git a/arch/riscv/include/asm/global_data.h 
b/arch/riscv/include/asm/global_data.h
index d3a0b1d221..095484a635 100644
--- a/arch/riscv/include/asm/global_data.h
+++ b/arch/riscv/include/asm/global_data.h
@@ -18,7 +18,7 @@
  struct arch_global_data {
        long boot_hart;         /* boot hart id */
        phys_addr_t firmware_fdt_addr;
-#ifdef CONFIG_SIFIVE_CLINT
+#if CONFIG_IS_ENABLED(SIFIVE_CLINT)
        void __iomem *clint;    /* clint base address */
  #endif
  #ifdef CONFIG_ANDES_PLIC
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index d08cbe9b79..c4cc41434b 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_CMD_BOOTI) += bootm.o image.o
  obj-$(CONFIG_CMD_GO) += boot.o
  obj-y += cache.o
  ifeq ($(CONFIG_$(SPL_)RISCV_MMODE),y)
-obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
+obj-$(CONFIG_$(SPL_)SIFIVE_CLINT) += sifive_clint.o
  obj-$(CONFIG_ANDES_PLIC) += andes_plic.o
  else
  obj-$(CONFIG_SBI) += sbi.o
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index eb5c48cc6c..2ebdeab0ce 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -19,7 +19,7 @@ obj-$(CONFIG_RENESAS_OSTM_TIMER) += ostm_timer.o
  obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o
  obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o
  obj-$(CONFIG_SANDBOX_TIMER)   += sandbox_timer.o
-obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint_timer.o
+obj-$(CONFIG_$(SPL_)SIFIVE_CLINT) += sifive_clint_timer.o
  obj-$(CONFIG_STI_TIMER)               += sti-timer.o
  obj-$(CONFIG_STM32_TIMER)     += stm32_timer.o
  obj-$(CONFIG_X86_TSC_TIMER)   += tsc_timer.o


Reviewed-by: Sean Anderson <sean...@gmail.com>

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