qemu/hw/ppc.c
bellard 9fddaa0c0c PowerPC merge: real time TB and decrementer - faster and simpler exception handling (Jocelyn Mayer)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@841 c046a42c-6fe2-441c-8c8c-71466251a162
2004-05-21 12:59:32 +00:00

216 lines
6.2 KiB
C

/*
* QEMU generic PPC hardware System Emulator
*
* Copyright (c) 2003-2004 Jocelyn Mayer
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "vl.h"
void ppc_prep_init (int ram_size, int vga_ram_size, int boot_device,
DisplayState *ds, const char **fd_filename, int snapshot,
const char *kernel_filename, const char *kernel_cmdline,
const char *initrd_filename);
/*****************************************************************************/
/* PPC time base and decrementer emulation */
//#define DEBUG_TB
struct ppc_tb_t {
/* Time base management */
int64_t tb_offset; /* Compensation */
uint32_t tb_freq; /* TB frequency */
/* Decrementer management */
uint64_t decr_next; /* Tick for next decr interrupt */
struct QEMUTimer *decr_timer;
};
static inline uint64_t cpu_ppc_get_tb (ppc_tb_t *tb_env)
{
/* TB time in tb periods */
return muldiv64(qemu_get_clock(vm_clock) + tb_env->tb_offset,
tb_env->tb_freq, ticks_per_sec);
}
uint32_t cpu_ppc_load_tbl (CPUState *env)
{
ppc_tb_t *tb_env = env->tb_env;
uint64_t tb;
tb = cpu_ppc_get_tb(tb_env);
#ifdef DEBUG_TB
{
static int last_time;
int now;
now = time(NULL);
if (last_time != now) {
last_time = now;
printf("%s: tb=0x%016lx %d %08lx\n",
__func__, tb, now, tb_env->tb_offset);
}
}
#endif
return tb & 0xFFFFFFFF;
}
uint32_t cpu_ppc_load_tbu (CPUState *env)
{
ppc_tb_t *tb_env = env->tb_env;
uint64_t tb;
tb = cpu_ppc_get_tb(tb_env);
#ifdef DEBUG_TB
printf("%s: tb=0x%016lx\n", __func__, tb);
#endif
return tb >> 32;
}
static void cpu_ppc_store_tb (ppc_tb_t *tb_env, uint64_t value)
{
tb_env->tb_offset = muldiv64(value, ticks_per_sec, tb_env->tb_freq)
- qemu_get_clock(vm_clock);
#ifdef DEBUG_TB
printf("%s: tb=0x%016lx offset=%08x\n", __func__, value);
#endif
}
void cpu_ppc_store_tbu (CPUState *env, uint32_t value)
{
ppc_tb_t *tb_env = env->tb_env;
cpu_ppc_store_tb(tb_env,
((uint64_t)value << 32) | cpu_ppc_load_tbl(env));
}
void cpu_ppc_store_tbl (CPUState *env, uint32_t value)
{
ppc_tb_t *tb_env = env->tb_env;
cpu_ppc_store_tb(tb_env,
((uint64_t)cpu_ppc_load_tbu(env) << 32) | value);
}
uint32_t cpu_ppc_load_decr (CPUState *env)
{
ppc_tb_t *tb_env = env->tb_env;
uint32_t decr;
decr = muldiv64(tb_env->decr_next - qemu_get_clock(vm_clock),
tb_env->tb_freq, ticks_per_sec);
#ifdef DEBUG_TB
printf("%s: 0x%08x\n", __func__, decr);
#endif
return decr;
}
/* When decrementer expires,
* all we need to do is generate or queue a CPU exception
*/
static inline void cpu_ppc_decr_excp (CPUState *env)
{
/* Raise it */
#ifdef DEBUG_TB
printf("raise decrementer exception\n");
#endif
cpu_interrupt(env, CPU_INTERRUPT_TIMER);
}
static void _cpu_ppc_store_decr (CPUState *env, uint32_t decr,
uint32_t value, int is_excp)
{
ppc_tb_t *tb_env = env->tb_env;
uint64_t now, next;
#ifdef DEBUG_TB
printf("%s: 0x%08x => 0x%08x\n", __func__, decr, value);
#endif
now = qemu_get_clock(vm_clock);
next = now + muldiv64(value, ticks_per_sec, tb_env->tb_freq);
if (is_excp)
next += tb_env->decr_next - now;
if (next == now)
next++;
tb_env->decr_next = next;
/* Adjust timer */
qemu_mod_timer(tb_env->decr_timer, next);
/* If we set a negative value and the decrementer was positive,
* raise an exception.
*/
if ((value & 0x80000000) && !(decr & 0x80000000))
cpu_ppc_decr_excp(env);
}
void cpu_ppc_store_decr (CPUState *env, uint32_t value)
{
_cpu_ppc_store_decr(env, cpu_ppc_load_decr(env), value, 0);
}
static void cpu_ppc_decr_cb (void *opaque)
{
_cpu_ppc_store_decr(opaque, 0x00000000, 0xFFFFFFFF, 1);
}
/* Set up (once) timebase frequency (in Hz) */
ppc_tb_t *cpu_ppc_tb_init (CPUState *env, uint32_t freq)
{
ppc_tb_t *tb_env;
tb_env = qemu_mallocz(sizeof(ppc_tb_t));
if (tb_env == NULL)
return NULL;
env->tb_env = tb_env;
if (tb_env->tb_freq == 0 || 1) {
tb_env->tb_freq = freq;
/* Create new timer */
tb_env->decr_timer =
qemu_new_timer(vm_clock, &cpu_ppc_decr_cb, env);
/* There is a bug in 2.4 kernels:
* if a decrementer exception is pending when it enables msr_ee,
* it's not ready to handle it...
*/
_cpu_ppc_store_decr(env, 0xFFFFFFFF, 0xFFFFFFFF, 0);
}
return tb_env;
}
#if 0
/*****************************************************************************/
/* Handle system reset (for now, just stop emulation) */
void cpu_ppc_reset (CPUState *env)
{
printf("Reset asked... Stop emulation\n");
abort();
}
#endif
/*****************************************************************************/
void ppc_init (int ram_size, int vga_ram_size, int boot_device,
DisplayState *ds, const char **fd_filename, int snapshot,
const char *kernel_filename, const char *kernel_cmdline,
const char *initrd_filename)
{
/* For now, only PREP is supported */
return ppc_prep_init(ram_size, vga_ram_size, boot_device, ds, fd_filename,
snapshot, kernel_filename, kernel_cmdline,
initrd_filename);
}