drivers/cpufreq/ppc_cbe_cpufreq_pervasive.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * pervasive backend for the cbe_cpufreq driver
   4  *
   5  * This driver makes use of the pervasive unit to
   6  * engage the desired frequency.
   7  *
   8  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
   9  *
  10  * Author: Christian Krafft <krafft@de.ibm.com>
  11  */
  12
  13 #include <linux/io.h>
  14 #include <linux/kernel.h>
  15 #include <linux/time.h>
  16 #include <asm/machdep.h>
  17 #include <asm/hw_irq.h>
  18 #include <asm/cell-regs.h>
  19
  20 #include "ppc_cbe_cpufreq.h"
  21
  22 /* to write to MIC register */
  23 static u64 MIC_Slow_Fast_Timer_table[] = {
  24         [0 ... 7] = 0x007fc00000000000ull,
  25 };
  26
  27 /* more values for the MIC */
  28 static u64 MIC_Slow_Next_Timer_table[] = {
  29         0x0000240000000000ull,
  30         0x0000268000000000ull,
  31         0x000029C000000000ull,
  32         0x00002D0000000000ull,
  33         0x0000300000000000ull,
  34         0x0000334000000000ull,
  35         0x000039C000000000ull,
  36         0x00003FC000000000ull,
  37 };
  38
  39
  40 int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
  41 {
  42         struct cbe_pmd_regs __iomem *pmd_regs;
  43         struct cbe_mic_tm_regs __iomem *mic_tm_regs;
  44         unsigned long flags;
  45         u64 value;
  46 #ifdef DEBUG
  47         long time;
  48 #endif
  49
  50         local_irq_save(flags);
  51
  52         mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
  53         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
  54
  55 #ifdef DEBUG
  56         time = jiffies;
  57 #endif
  58
  59         out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
  60         out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
  61
  62         out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
  63         out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
  64
  65         value = in_be64(&pmd_regs->pmcr);
  66         /* set bits to zero */
  67         value &= 0xFFFFFFFFFFFFFFF8ull;
  68         /* set bits to next pmode */
  69         value |= pmode;
  70
  71         out_be64(&pmd_regs->pmcr, value);
  72
  73 #ifdef DEBUG
  74         /* wait until new pmode appears in status register */
  75         value = in_be64(&pmd_regs->pmsr) & 0x07;
  76         while (value != pmode) {
  77                 cpu_relax();
  78                 value = in_be64(&pmd_regs->pmsr) & 0x07;
  79         }
  80
  81         time = jiffies  - time;
  82         time = jiffies_to_msecs(time);
  83         pr_debug("had to wait %lu ms for a transition using " \
  84                  "pervasive unit\n", time);
  85 #endif
  86         local_irq_restore(flags);
  87
  88         return 0;
  89 }
  90
  91
  92 int cbe_cpufreq_get_pmode(int cpu)
  93 {
  94         int ret;
  95         struct cbe_pmd_regs __iomem *pmd_regs;
  96
  97         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
  98         ret = in_be64(&pmd_regs->pmsr) & 0x07;
  99
 100         return ret;
 101 }
 102