2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
8 #include <linux/init.h>
11 #include <asm/setup.h>
14 #include <asm/mips-boards/generic.h>
16 unsigned long cpu_khz
;
18 static int mips_cpu_timer_irq
;
19 static int mips_cpu_perf_irq
;
21 static void mips_timer_dispatch(void)
23 do_IRQ(mips_cpu_timer_irq
);
26 static void mips_perf_dispatch(void)
28 do_IRQ(mips_cpu_perf_irq
);
31 static void __iomem
*status_reg
= (void __iomem
*)0xbf000410;
34 * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect.
36 static unsigned int __init
estimate_cpu_frequency(void)
38 unsigned int prid
= read_c0_prid() & (PRID_COMP_MASK
| PRID_IMP_MASK
);
39 unsigned int tick
= 0;
44 local_irq_save(flags
);
46 orig
= readl(status_reg
) & 0x2; /* get original sample */
47 /* wait for transition */
48 while ((readl(status_reg
) & 0x2) == orig
)
50 orig
= orig
^ 0x2; /* flip the bit */
54 /* wait 1 second (the sampling clock transitions every 10ms) */
56 /* wait for transition */
57 while ((readl(status_reg
) & 0x2) == orig
)
59 orig
= orig
^ 0x2; /* flip the bit */
63 freq
= read_c0_count();
65 local_irq_restore(flags
);
67 mips_hpt_frequency
= freq
;
69 /* Adjust for processor */
70 if ((prid
!= (PRID_COMP_MIPS
| PRID_IMP_20KC
)) &&
71 (prid
!= (PRID_COMP_MIPS
| PRID_IMP_25KF
)))
74 freq
+= 5000; /* rounding */
80 void read_persistent_clock(struct timespec
*ts
)
86 static void __init
plat_perf_setup(void)
88 if (cp0_perfcount_irq
>= 0) {
90 set_vi_handler(cp0_perfcount_irq
, mips_perf_dispatch
);
91 mips_cpu_perf_irq
= MIPS_CPU_IRQ_BASE
+ cp0_perfcount_irq
;
95 unsigned int get_c0_compare_int(void)
98 set_vi_handler(cp0_compare_irq
, mips_timer_dispatch
);
99 mips_cpu_timer_irq
= MIPS_CPU_IRQ_BASE
+ cp0_compare_irq
;
100 return mips_cpu_timer_irq
;
103 void __init
plat_time_init(void)
105 unsigned int est_freq
;
107 est_freq
= estimate_cpu_frequency();
109 pr_debug("CPU frequency %d.%02d MHz\n", (est_freq
/ 1000000),
110 (est_freq
% 1000000) * 100 / 1000000);
112 cpu_khz
= est_freq
/ 1000;
114 mips_scroll_message();