[CPUFREQ] Longhaul - Hook into ACPI C states.

Minimal change necessary for hardware support.

Changes in longhaul.c:
- most important - now C3 state is causing transition,
- code responsible for clearing "bus master" bit removed,
- protect bcr2 transition in the same way as longhaul.

Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>

2 files changed, 109 insertions, 87 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/Kconfig b/arch/i386/kernel/cpu/cpufreq/Kconfig
index e44a4c6a4fe5..c593d73908f7 100644
--- a/arch/i386/kernel/cpu/cpufreq/Kconfig
+++ b/arch/i386/kernel/cpu/cpufreq/Kconfig
@@ -202,7 +202,7 @@ config X86_LONGRUN
 config X86_LONGHAUL
         tristate "VIA Cyrix III Longhaul"
         select CPU_FREQ_TABLE
-        depends on BROKEN
+        depends on ACPI_PROCESSOR
         help
           This adds the CPUFreq driver for VIA Samuel/CyrixIII,
           VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
diff --git a/arch/i386/kernel/cpu/cpufreq/longhaul.c b/arch/i386/kernel/cpu/cpufreq/longhaul.c
index 146f607e9c44..d735cb460612 100644
--- a/arch/i386/kernel/cpu/cpufreq/longhaul.c
+++ b/arch/i386/kernel/cpu/cpufreq/longhaul.c
@@ -29,11 +29,13 @@
 #include <linux/cpufreq.h>
 #include <linux/slab.h>
 #include <linux/string.h>
-#include <linux/pci.h>
 
 #include <asm/msr.h>
 #include <asm/timex.h>
 #include <asm/io.h>
+#include <asm/acpi.h>
+#include <linux/acpi.h>
+#include <acpi/processor.h>
 
 #include "longhaul.h"
 
@@ -56,6 +58,8 @@ static int minvid, maxvid;
 static unsigned int minmult, maxmult;
 static int can_scale_voltage;
 static int vrmrev;
+static struct acpi_processor *pr = NULL;
+static struct acpi_processor_cx *cx = NULL;
 
 /* Module parameters */
 static int dont_scale_voltage;
@@ -118,84 +122,64 @@ static int longhaul_get_cpu_mult(void)
         return eblcr_table[invalue];
 }
 
+/* For processor with BCR2 MSR */
 
-static void do_powersaver(union msr_longhaul *longhaul,
-                        unsigned int clock_ratio_index)
+static void do_longhaul1(int cx_address, unsigned int clock_ratio_index)
 {
-        struct pci_dev *dev;
-        unsigned long flags;
-        unsigned int tmp_mask;
-        int version;
-        int i;
-        u16 pci_cmd;
-        u16 cmd_state[64];
+        union msr_bcr2 bcr2;
+        u32 t;
 
-        switch (cpu_model) {
-        case CPU_EZRA_T:
-                version = 3;
-                break;
-        case CPU_NEHEMIAH:
-                version = 0xf;
-                break;
-        default:
-                return;
-        }
+        rdmsrl(MSR_VIA_BCR2, bcr2.val);
+        /* Enable software clock multiplier */
+        bcr2.bits.ESOFTBF = 1;
+        bcr2.bits.CLOCKMUL = clock_ratio_index;
 
-        rdmsrl(MSR_VIA_LONGHAUL, longhaul->val);
-        longhaul->bits.SoftBusRatio = clock_ratio_index & 0xf;
-        longhaul->bits.SoftBusRatio4 = (clock_ratio_index & 0x10) >> 4;
-        longhaul->bits.EnableSoftBusRatio = 1;
-        longhaul->bits.RevisionKey = 0;
+        /* Sync to timer tick */
+        safe_halt();
+        ACPI_FLUSH_CPU_CACHE();
+        /* Change frequency on next halt or sleep */
+        wrmsrl(MSR_VIA_BCR2, bcr2.val);
+        /* Invoke C3 */
+        inb(cx_address);
+        /* Dummy op - must do something useless after P_LVL3 read */
+        t = inl(acpi_fadt.xpm_tmr_blk.address);
+
+        /* Disable software clock multiplier */
+        local_irq_disable();
+        rdmsrl(MSR_VIA_BCR2, bcr2.val);
+        bcr2.bits.ESOFTBF = 0;
+        wrmsrl(MSR_VIA_BCR2, bcr2.val);
+}
 
-        preempt_disable();
-        local_irq_save(flags);
+/* For processor with Longhaul MSR */
 
-        /*
-         * get current pci bus master state for all devices
-         * and clear bus master bit
-         */
-        dev = NULL;
-        i = 0;
-        do {
-                dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
-                if (dev != NULL) {
-                        pci_read_config_word(dev, PCI_COMMAND, &pci_cmd);
-                        cmd_state[i++] = pci_cmd;
-                        pci_cmd &= ~PCI_COMMAND_MASTER;
-                        pci_write_config_word(dev, PCI_COMMAND, pci_cmd);
-                }
-        } while (dev != NULL);
+static void do_powersaver(int cx_address, unsigned int clock_ratio_index)
+{
+        union msr_longhaul longhaul;
+        u32 t;
 
-        tmp_mask=inb(0x21);     /* works on C3. save mask. */
-        outb(0xFE,0x21);        /* TMR0 only */
-        outb(0xFF,0x80);        /* delay */
+        rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
+        longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
+        longhaul.bits.SoftBusRatio = clock_ratio_index & 0xf;
+        longhaul.bits.SoftBusRatio4 = (clock_ratio_index & 0x10) >> 4;
 
+        /* Sync to timer tick */
         safe_halt();
-        wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
-        halt();
-
+        ACPI_FLUSH_CPU_CACHE();
+        /* Change frequency on next halt or sleep */
+        wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
+        /* Invoke C3 */
+        inb(cx_address);
+        /* Dummy op - must do something useless after P_LVL3 read */
+        t = inl(acpi_fadt.xpm_tmr_blk.address);
+
+        /* Disable bus ratio bit */
         local_irq_disable();
-
-        outb(tmp_mask,0x21);    /* restore mask */
-
-        /* restore pci bus master state for all devices */
-        dev = NULL;
-        i = 0;
-        do {
-                dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
-                if (dev != NULL) {
-                        pci_cmd = cmd_state[i++];
-                        pci_write_config_byte(dev, PCI_COMMAND, pci_cmd);
-                }
-        } while (dev != NULL);
-        local_irq_restore(flags);
-        preempt_enable();
-
-        /* disable bus ratio bit */
-        rdmsrl(MSR_VIA_LONGHAUL, longhaul->val);
-        longhaul->bits.EnableSoftBusRatio = 0;
-        longhaul->bits.RevisionKey = version;
-        wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
+        longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
+        longhaul.bits.EnableSoftBusRatio = 0;
+        longhaul.bits.EnableSoftBSEL = 0;
+        longhaul.bits.EnableSoftVID = 0;
+        wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 }
 
 /**
@@ -209,9 +193,9 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
 {
         int speed, mult;
         struct cpufreq_freqs freqs;
-        union msr_longhaul longhaul;
-        union msr_bcr2 bcr2;
         static unsigned int old_ratio=-1;
+        unsigned long flags;
+        unsigned int pic1_mask, pic2_mask;
 
         if (old_ratio == clock_ratio_index)
                 return;
@@ -234,6 +218,20 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
         dprintk ("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n",
                         fsb, mult/10, mult%10, print_speed(speed/1000));
 
+        preempt_disable();
+        local_irq_save(flags);
+
+        pic2_mask = inb(0xA1);
+        pic1_mask = inb(0x21);  /* works on C3. save mask. */
+        outb(0xFF,0xA1);        /* Overkill */
+        outb(0xFE,0x21);        /* TMR0 only */
+
+        /* Disable bus master arbitration */
+        if (pr->flags.bm_check) {
+                acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
+                                  ACPI_MTX_DO_NOT_LOCK);
+        }
+
         switch (longhaul_version) {
 
         /*
@@ -245,20 +243,7 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
          */
         case TYPE_LONGHAUL_V1:
         case TYPE_LONGHAUL_V2:
-                rdmsrl (MSR_VIA_BCR2, bcr2.val);
-                /* Enable software clock multiplier */
-                bcr2.bits.ESOFTBF = 1;
-                bcr2.bits.CLOCKMUL = clock_ratio_index;
-                local_irq_disable();
-                wrmsrl (MSR_VIA_BCR2, bcr2.val);
-                safe_halt();
-
-                /* Disable software clock multiplier */
-                rdmsrl (MSR_VIA_BCR2, bcr2.val);
-                bcr2.bits.ESOFTBF = 0;
-                local_irq_disable();
-                wrmsrl (MSR_VIA_BCR2, bcr2.val);
-                local_irq_enable();
+                do_longhaul1(cx->address, clock_ratio_index);
                 break;
 
         /*
@@ -273,10 +258,22 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
          * to work in practice.
          */
         case TYPE_POWERSAVER:
-                do_powersaver(&longhaul, clock_ratio_index);
+                do_powersaver(cx->address, clock_ratio_index);
                 break;
         }
 
+        /* Enable bus master arbitration */
+        if (pr->flags.bm_check) {
+                acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
+                                  ACPI_MTX_DO_NOT_LOCK);
+        }
+
+        outb(pic2_mask,0xA1);   /* restore mask */
+        outb(pic1_mask,0x21);
+
+        local_irq_restore(flags);
+        preempt_enable();
+
         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 }
 
@@ -527,6 +524,18 @@ static unsigned int longhaul_get(unsigned int cpu)
         return calc_speed(longhaul_get_cpu_mult());
 }
 
+acpi_status longhaul_walk_callback(acpi_handle obj_handle,
+                                  u32 nesting_level,
+                                  void *context, void **return_value)
+{
+        struct acpi_device *d;
+
+        if ( acpi_bus_get_device(obj_handle, &d) ) {
+                return 0;
+        }
+        *return_value = (void *)acpi_driver_data(d);
+        return 1;
+}
 
 static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
 {
@@ -534,6 +543,15 @@ static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
         char *cpuname=NULL;
         int ret;
 
+        /* Check ACPI support for C3 state */
+        acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
+                         &longhaul_walk_callback, NULL, (void *)&pr);
+        if (pr == NULL) goto err_acpi;
+
+        cx = &pr->power.states[ACPI_STATE_C3];
+        if (cx == NULL || cx->latency > 1000) goto err_acpi;
+
+        /* Now check what we have on this motherboard */
         switch (c->x86_model) {
         case 6:
                 cpu_model = CPU_SAMUEL;
@@ -634,6 +652,10 @@ static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
         cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);
 
         return 0;
+
+err_acpi:
+        printk(KERN_ERR PFX "No ACPI support for CPU frequency changes.\n");
+        return -ENODEV;
 }
 
 static int __devexit longhaul_cpu_exit(struct cpufreq_policy *policy)