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path: root/arch/riscv/cpu/start.S
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2019-04-08riscv: hang if relocation of secondary harts failsLukas Auer
Print an error message and hang if smp_call_function() returns an error, indicating that relocation of the secondary harts has failed. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Anup Patel <anup.patel@wdc.com>
2019-04-08riscv: do not rely on hart ID passed by previous boot stageLukas Auer
RISC-V U-Boot expects the hart ID to be passed to it via register a0 by the previous boot stage. Machine mode firmware such as BBL and OpenSBI do this when starting their payload (U-Boot) in supervisor mode. If U-Boot is running in machine mode, this task must be handled by the boot ROM. Explicitly populate register a0 with the hart ID from the mhartid CSR to avoid possible problems on RISC-V processors with a boot ROM that does not handle this task. Suggested-by: Rick Chen <rick@andestech.com> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Rick Chen <rick@andestech.com> Tested-by: Rick Chen <rick@andestech.com>
2019-04-08riscv: add support for multi-hart systemsLukas Auer
On RISC-V, all harts boot independently. To be able to run on a multi-hart system, U-Boot must be extended with the functionality to manage all harts in the system. All harts entering U-Boot are registered in the available_harts mask stored in global data. A hart lottery system as used in the Linux kernel selects the hart U-Boot runs on. All other harts are halted. U-Boot can delegate functions to them using smp_call_function(). Every hart has a valid pointer to the global data structure and a 8KiB stack by default. The stack size is set with CONFIG_STACK_SIZE_SHIFT. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com>
2019-04-08riscv: save hart ID in register tp instead of s0Lukas Auer
The hart ID passed by the previous boot stage is currently stored in register s0. If we divert the control flow inside a function, which is required as part of multi-hart support, the function epilog may not be called, clobbering register s0. Save the hart ID in the unallocatable register tp instead to protect the hart ID. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Rick Chen <rick@andestech.com> Reviewed-by: Anup Patel <anup.patel@wdc.com>
2019-04-08riscv: delay initialization of caches and debug UARTLukas Auer
Move the initialization of the caches and the debug UART until after board_init_f_init_reserve. This is in preparation for SMP support, where code prior to this point will be executed by all harts. This ensures that initialization will only be performed once on the main hart running U-Boot. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2018-12-18riscv: Save boot hart id to the global dataBin Meng
At present the hart id passed via a0 in the U-Boot entry is saved to s0 at the beginning but does not preserve later. Save it to the global data structure so that it can be used later. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup@brainfault.org>
2018-12-18riscv: Move trap handler codes to mtrap.SBin Meng
Currently the M-mode trap handler codes are in start.S. For future extension, move them to a separate file mtrap.S. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Anup Patel <anup@brainfault.org>
2018-12-05riscv: ax25-ae350: Pass dtb address to u-boot with a1 registerRick Chen
ax25-ae350 use CONFIG_OF_BOARD via a2 and CONFIG_SYS_SDRAM_BASE to boot from ram which allow the board to override the fdt address originally. But after this patch riscv: save hart ID and device tree passed by prior boot stage It provide prior_stage_fdt_address which offer a temporary memory address to keep the dtb address passing from loader(gdb) to u-boot with a1. So passing via a2 and CONFIG_SYS_SDRAM_BASE is redundant and can be removed. And it also somehow may corrupted BBL if it was be arranged in CONFIG_SYS_SDRAM_BASE. In board_fdt_blob_setup() When boting from ram: prior_stage_fdt_address will be use to reserved dtb temporarily. When booting from ROM: dtb will be pre-burned in CONFIG_SYS_FDT_BASE, if it is flash base. Or CONFIG_SYS_FDT_BASE maybe a memory map space (NOT RAM or ROM) which is provided by HW. Signed-off-by: Rick Chen <rick@andestech.com> Cc: Greentime Hu <greentime@andestech.com>
2018-12-05riscv: Add kconfig option to run U-Boot in S-modeAnup Patel
This patch adds kconfig option RISCV_SMODE to run U-Boot in S-mode. When this opition is enabled we use s<xyz> CSRs instead of m<xyz> CSRs. It is important to note that there is no equivalent S-mode CSR for misa and mhartid CSRs so we expect M-mode runtime firmware (BBL or equivalent) to emulate misa and mhartid CSR read. In-future, we will have more patches to avoid accessing misa and mhartid CSRs from S-mode. Signed-off-by: Anup Patel <anup@brainfault.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
2018-11-26riscv: cache: Implement i/dcache [status, enable, disable]Rick Chen
AndeStar RISC-V(V5) provide mcache_ctl register which can configure I/D cache as enabled or disabled. This CSR will be encapsulated by CONFIG_RISCV_NDS. If you want to configure cache on AndeStar V5 AE350 platform. YOu can enable [*] AndeStar V5 ISA support by make menuconfig. This approach also provide the expansion when the vender specific features are going to join in. Signed-off-by: Rick Chen <rick@andestech.com> Cc: Greentime Hu <greentime@andestech.com>
2018-11-26riscv: save hart ID and device tree passed by prior boot stageLukas Auer
Store the hart ID and device tree passed by the prior boot stage (in a0 and a1) in registers s0 and s1. Replace one use of s1 in start.S to avoid overwriting it. The device tree is also stored in memory to make it available to U-Boot with the configuration CONFIG_OF_PRIOR_STAGE. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Rick Chen <rick@andestech.com>
2018-11-26riscv: do not blindly modify the mstatus CSRLukas Auer
The mstatus CSR includes WPRI (writes preserve values, reads ignore values) fields and must therefore not be set to zero without preserving these fields. It is not apparent why mstatus is set to zero here since it is not required for U-Boot to run. Remove it. This instruction and others encode zero as an immediate. RISC-V has the zero register for this purpose. Replace the immediates with the zero register. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Rick Chen <rick@andestech.com>
2018-11-26riscv: remove unused labels in start.SLukas Auer
The labels nmi_vector, trap_vector and handle_reset in start.S are not used for RISC-V. Remove them. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2018-11-26Drop CONFIG_INIT_CRITICALBin Meng
This is now deprecated and no board is using it. Drop it. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
2018-11-26riscv: align mtvec on a 4-byte boundaryLukas Auer
The machine trap-vector base address (mtvec) must be aligned on a 4-byte boundary. Add the necessary align directive to trap_entry. This patch also removes the global directive for trap_entry, which is not required. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2018-11-26riscv: fix inconsistent use of spaces and tabs in start.SLukas Auer
start.S uses both tabs and spaces after instructions. Fix this by only using tabs after instructions. Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Rick Chen <rick@andestech.com>
2018-10-03riscv: Make start.S available for all targetsBin Meng
Currently start.S is inside arch/riscv/cpu/ax25/, but it can be common for all RISC-V targets. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>