diff options
Diffstat (limited to 'arch/kvx/cpu/start.S')
| -rw-r--r-- | arch/kvx/cpu/start.S | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/arch/kvx/cpu/start.S b/arch/kvx/cpu/start.S new file mode 100644 index 0000000000..342c7d38a5 --- /dev/null +++ b/arch/kvx/cpu/start.S @@ -0,0 +1,187 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2019 Kalray Inc. + */ + +#include <linux/linkage.h> +#include <asm/privilege.h> +#include <asm/sys_arch.h> + +#define PS_VAL_WFXL(__field, __val) \ + SFR_SET_VAL_WFXL(PS, __field, __val) + +#define PS_WFXL_START_VALUE PS_VAL_WFXL(HLE, 1) | \ + PS_VAL_WFXL(USE, 1) | \ + PS_VAL_WFXL(DCE, 1) | \ + PS_VAL_WFXL(ICE, 1) | \ + PS_VAL_WFXL(V64, 1) | \ + PS_VAL_WFXL(ET, 0) + +#define PCR_VAL_WFXM(__field, __val) \ + SFR_SET_VAL_WFXM(PCR, __field, __val) + +#define PCR_WFXM_START_VALUE PCR_VAL_WFXM(L1CE, 1) + +/* Enable STOP in WS */ +#define WS_ENABLE_WU2 (KVX_SFR_WS_WU2_MASK) + +#define WS_WFXL_VALUE (WS_ENABLE_WU2) + +/* + * This is our entry point. When entering from bootloader, + * the following registers are set: + * $r0 is a magic "KALARGV1" (FSBL_PARAM_MAGIC) indicating parameters are passed + * $r1 Device tree pointer + * + * WARNING WARNING WARNING + * ! DO NOT CLOBBER THEM ! + * WARNING WARNING WARNING + * + * Try to use register above $r20 to ease parameter adding in future + */ +.section .startup, "ax" +ENTRY(kvx_start) + /* (Re)initialize performance counter */ + make $r20 = 0x00000000 + ;; + set $pmc = $r20 + ;; + call asm_init_pl + ;; + /* Setup default processor status */ + make $r25 = PS_WFXL_START_VALUE + ;; + wfxl $ps, $r25 + ;; + make $r25 = PCR_WFXM_START_VALUE + ;; + wfxm $pcr, $r25 + ;; + /* Clear BSS */ + make $r22 = __bss_stop + make $r21 = __bss_start + ;; + sbfd $r22 = $r21, $r22 + make $r24 = 0 + ;; + /* Divide by 16 for hardware loop */ + srld $r22 = $r22, 4 + make $r25 = 0 + ;; + /* Clear bss with hardware loop */ + loopdo $r22, clear_bss_done + ;; + sq 0[$r21] = $r24r25 + addd $r21 = $r21, 16 + ;; + clear_bss_done: + /* Setup stack */ + make $sp = __stack_start + ;; + call kvx_lowlevel_setup + ;; + call kvx_start_barebox + ;; + goto kvx_proc_power_off + ;; +ENDPROC(kvx_start) + +#define request_ownership(__pl) ;\ + make $r21 = SYO_WFXL_VALUE_##__pl ;\ + ;; ;\ + wfxl $syow, $r21 ;\ + ;; ;\ + make $r21 = HTO_WFXL_VALUE_##__pl ;\ + ;; ;\ + wfxl $htow, $r21 ;\ + ;; ;\ + make $r21 = MO_WFXL_VALUE_##__pl ;\ + make $r22 = MO_WFXM_VALUE_##__pl ;\ + ;; ;\ + wfxl $mow, $r21 ;\ + ;; ;\ + wfxm $mow, $r22 ;\ + ;; ;\ + make $r21 = ITO_WFXL_VALUE_##__pl ;\ + make $r22 = ITO_WFXM_VALUE_##__pl ;\ + ;; ;\ + wfxl $itow, $r21 ;\ + ;; ;\ + wfxm $itow, $r22 ;\ + ;; ;\ + make $r21 = PSO_WFXL_VALUE_##__pl ;\ + make $r22 = PSO_WFXM_VALUE_##__pl ;\ + ;; ;\ + wfxl $psow, $r21 ;\ + ;; ;\ + wfxm $psow, $r22 ;\ + ;; ;\ + make $r21 = DO_WFXL_VALUE_##__pl ;\ + ;; ;\ + wfxl $dow, $r21 ;\ + ;; + +/** + * Initialize privilege level + */ +ENTRY(asm_init_pl) + get $r21 = $ps + ;; + /* Extract privilege level from $ps to check if we need to + * lower our privilege level (we might already be in PL1) + */ + extfz $r20 = $r21, KVX_SFR_END(PS_PL), KVX_SFR_START(PS_PL) + ;; + /* If our privilege level is 0, then we need to lower in execution level + * to ring 1 in order to let the debug routines be inserted at runtime + * by the JTAG. In both case, we will request the resources we need for + * barebox to run. + */ + cb.deqz $r20? delegate_pl + ;; + /* + * When someone is already above us, request the resources we need to + * run barebox . No need to request double exception or ECC traps for + * instance. When doing so, the more privileged level will trap for + * permission and delegate us the required resources. + */ + request_ownership(PL_CUR) + ;; + ret + ;; +delegate_pl: + request_ownership(PL_CUR_PLUS_1) + ;; + /* Copy our $ps into $sps for 1:1 restoration */ + get $r22 = $ps + ;; + /* We will return to $ra after rfe */ + get $r21 = $ra + /* Set privilege level to +1 in $sps (relative level from the + * current one) + */ + addd $r22 = $r22, PL_CUR_PLUS_1 + ;; + set $spc = $r21 + ;; + set $sps = $r22 + ;; + /* When using rfe, $spc and $sps will be restored in $ps and $pc, + * We will then return to the caller ($ra) in current PL + 1 + */ + rfe + ;; +ENDPROC(asm_init_pl) + +ENTRY(kvx_proc_power_off): + d1inval + make $r1 = WS_WFXL_VALUE + ;; + /* Enable STOP */ + wfxl $ws, $r1 + ;; +1: stop + ;; + goto 1b + ;; +ENDPROC(kvx_proc_power_off) |