drivers/cpufreq/ppc_cbe_cpufreq_pervasive.c

   1 /*
   2  * pervasive backend for the cbe_cpufreq driver
   3  *
   4  * This driver makes use of the pervasive unit to
   5  * engage the desired frequency.
   6  *
   7  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
   8  *
   9  * Author: Christian Krafft <krafft@de.ibm.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26 #include <linux/io.h>
  27 #include <linux/kernel.h>
  28 #include <linux/time.h>
  29 #include <asm/machdep.h>
  30 #include <asm/hw_irq.h>
  31 #include <asm/cell-regs.h>
  32
  33 #include "ppc_cbe_cpufreq.h"
  34
  35 /* to write to MIC register */
  36 static u64 MIC_Slow_Fast_Timer_table[] = {
  37         [0 ... 7] = 0x007fc00000000000ull,
  38 };
  39
  40 /* more values for the MIC */
  41 static u64 MIC_Slow_Next_Timer_table[] = {
  42         0x0000240000000000ull,
  43         0x0000268000000000ull,
  44         0x000029C000000000ull,
  45         0x00002D0000000000ull,
  46         0x0000300000000000ull,
  47         0x0000334000000000ull,
  48         0x000039C000000000ull,
  49         0x00003FC000000000ull,
  50 };
  51
  52
  53 int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
  54 {
  55         struct cbe_pmd_regs __iomem *pmd_regs;
  56         struct cbe_mic_tm_regs __iomem *mic_tm_regs;
  57         unsigned long flags;
  58         u64 value;
  59 #ifdef DEBUG
  60         long time;
  61 #endif
  62
  63         local_irq_save(flags);
  64
  65         mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
  66         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
  67
  68 #ifdef DEBUG
  69         time = jiffies;
  70 #endif
  71
  72         out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
  73         out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
  74
  75         out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
  76         out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
  77
  78         value = in_be64(&pmd_regs->pmcr);
  79         /* set bits to zero */
  80         value &= 0xFFFFFFFFFFFFFFF8ull;
  81         /* set bits to next pmode */
  82         value |= pmode;
  83
  84         out_be64(&pmd_regs->pmcr, value);
  85
  86 #ifdef DEBUG
  87         /* wait until new pmode appears in status register */
  88         value = in_be64(&pmd_regs->pmsr) & 0x07;
  89         while (value != pmode) {
  90                 cpu_relax();
  91                 value = in_be64(&pmd_regs->pmsr) & 0x07;
  92         }
  93
  94         time = jiffies  - time;
  95         time = jiffies_to_msecs(time);
  96         pr_debug("had to wait %lu ms for a transition using " \
  97                  "pervasive unit\n", time);
  98 #endif
  99         local_irq_restore(flags);
 100
 101         return 0;
 102 }
 103
 104
 105 int cbe_cpufreq_get_pmode(int cpu)
 106 {
 107         int ret;
 108         struct cbe_pmd_regs __iomem *pmd_regs;
 109
 110         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
 111         ret = in_be64(&pmd_regs->pmsr) & 0x07;
 112
 113         return ret;
 114 }
 115