fff070f2cb
This is a work in progress port to the mntreform2 laptop. Working so far: - mmu (same as raspberry pi 3b+) - arm generic timer - gicv3 - uart1 - enet With access to the uart, one can netboot this kernel in u-boot using the following commands: > dhcp > bootm
115 lines
1.4 KiB
C
115 lines
1.4 KiB
C
#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "io.h"
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#include "ureg.h"
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#include "sysreg.h"
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static uvlong freq;
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enum {
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Enable = 1<<0,
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Imask = 1<<1,
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Istatus = 1<<2,
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};
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void
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clockshutdown(void)
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{
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}
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static void
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localclockintr(Ureg *ureg, void *)
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{
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timerintr(ureg, 0);
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}
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void
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clockinit(void)
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{
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syswr(PMCR_EL0, 1<<6 | 7);
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syswr(PMCNTENSET, 1<<31);
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syswr(PMUSERENR_EL0, 1<<2);
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syswr(CNTKCTL_EL1, 1<<1);
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syswr(CNTP_TVAL_EL0, ~0UL);
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syswr(CNTP_CTL_EL0, Enable);
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if(m->machno == 0){
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freq = sysrd(CNTFRQ_EL0);
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print("timer frequency %lld Hz\n", freq);
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}
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intrenable(IRQcntpns, localclockintr, nil, BUSUNKNOWN, "clock");
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}
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void
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timerset(uvlong next)
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{
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uvlong now;
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long period;
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now = fastticks(nil);
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period = next - now;
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syswr(CNTP_TVAL_EL0, period);
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}
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uvlong
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fastticks(uvlong *hz)
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{
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if(hz)
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*hz = freq;
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return sysrd(CNTPCT_EL0);
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}
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ulong
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perfticks(void)
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{
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return fastticks(nil);
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}
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ulong
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µs(void)
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{
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uvlong hz;
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uvlong t = fastticks(&hz);
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return (t * 1000000ULL) / hz;
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}
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void
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microdelay(int n)
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{
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ulong now;
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now = µs();
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while(µs() - now < n);
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}
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void
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delay(int n)
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{
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while(--n >= 0)
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microdelay(1000);
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}
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void
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synccycles(void)
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{
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static Ref r1, r2;
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int s;
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s = splhi();
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r2.ref = 0;
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incref(&r1);
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while(r1.ref != conf.nmach)
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;
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// syswr(PMCR_EL0, 1<<6 | 7);
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incref(&r2);
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while(r2.ref != conf.nmach)
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;
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r1.ref = 0;
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splx(s);
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}
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