[PATCH ] cell: enable pause(0) in cpu_idle

Max Aguilar maguilar at us.ibm.com
Thu Dec 15 07:13:02 EST 2005





This looks good to me, thanks for looking over the code.

Max Aguilar
Linux Kernel/Bootloader/Bring-Up
STI Design Center
(512) 838-5704  T/L 678-5704
maguilar at us.ibm.com

Arnd Bergmann <arnd at arndb.de> on 12/14/2005 12:10:18 PM

To:    linuxppc64-dev at ozlabs.org
cc:    Milton Miller <miltonm at bga.com>, Paul Mackerras <paulus at samba.org>,
       Max Aguilar/Austin/IBM at IBMUS
Subject:    [PATCH ] cell: enable pause(0) in cpu_idle


This patch enables support for pause(0) power management state
for the Cell Broadband Processor, which is import for power efficient
operation. The pervasive infrastructure will in the future enable
us to introduce more functionality specific to the Cell's
pervasive unit.

This version contains more changes according to comments from Milton.
More importantly, it now also works on DD2 hardware, after I have
fixed a bug in the initialization sequence.

From: Maximino Aguilar <maguilar at us.ibm.com>
Signed-off-by: Arnd Bergmann <arndb at de.ibm.com>

---

Paul, please merge this once Milton and Max have both acknowledged
the contents.

Max, I haven't gotten any reply from you on this patch so far.
Please tell us if the changes I have done to your code look
right!

Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/Makefile
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/Makefile
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/Makefile
@@ -1,4 +1,6 @@
 obj-y                                     += interrupt.o iommu.o setup.o
spider-pic.o
+obj-y                                     += pervasive.o
+
 obj-$(CONFIG_SMP)             += smp.o
 obj-$(CONFIG_SPU_FS)          += spufs/ spu_base.o
 builtin-spufs-$(CONFIG_SPU_FS)            += spu_syscalls.o
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/pervasive.c
===================================================================
--- /dev/null
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/pervasive.c
@@ -0,0 +1,192 @@
+/*
+ * CBE Pervasive Monitor and Debug
+ *
+ * (C) Copyright IBM Corporation 2005
+ *
+ * Authors: Maximino Aguilar (maguilar at us.ibm.com)
+ *          Michael N. Day (mnday at us.ibm.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#undef DEBUG
+
+#include <linux/config.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/percpu.h>
+#include <linux/types.h>
+#include <linux/kallsyms.h>
+
+#include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/prom.h>
+#include <asm/pgtable.h>
+#include <asm/reg.h>
+
+#include "pervasive.h"
+
+struct cbe_pervasive {
+            struct pmd_regs __iomem *regs;
+            unsigned int thread;
+};
+
+/* can't use per_cpu from setup_arch */
+static struct cbe_pervasive cbe_pervasive[NR_CPUS];
+
+static void __init cbe_enable_pause_zero(void)
+{
+            unsigned long thread_switch_control;
+            unsigned long temp_register;
+            struct cbe_pervasive *p;
+            int thread;
+
+            p = &cbe_pervasive[get_cpu()];
+
+            if (!cbe_pervasive->regs)
+                        return;
+
+            pr_debug("Power Management: CPU %d\n", smp_processor_id());
+
+             /* Enable Pause(0) control bit */
+            temp_register = in_be64(&p->regs->pm_control);
+
+            out_be64(&p->regs->pm_control,
+                         temp_register|PMD_PAUSE_ZERO_CONTROL);
+
+            /* Enable DEC and EE interrupt request */
+            thread_switch_control  = mfspr(SPRN_TSC_CELL);
+            thread_switch_control |= TSC_CELL_EE_ENABLE |
TSC_CELL_EE_BOOST;
+
+            switch ((mfspr(SPRN_CTRLF) & CTRL_CT)) {
+            case CTRL_CT0:
+                        thread_switch_control |= TSC_CELL_DEC_ENABLE_0;
+                        thread = 0;
+                        break;
+            case CTRL_CT1:
+                        thread_switch_control |= TSC_CELL_DEC_ENABLE_1;
+                        thread = 1;
+                        break;
+            default:
+                        printk(KERN_WARNING "%s: unknown configuration\n",
+                                    __FUNCTION__);
+                        thread = -1;
+                        break;
+            }
+
+            if (p->thread != thread)
+                        printk(KERN_WARNING "%s: device tree inconsistant,
"
+                                                     "cpu %i: %d/%d\n",
__FUNCTION__,
+                                                     smp_processor_id(),
+                                                     p->thread, thread);
+
+            mtspr(SPRN_TSC_CELL, thread_switch_control);
+
+            put_cpu();
+}
+
+static void cbe_idle(void)
+{
+            unsigned long ctrl;
+
+            cbe_enable_pause_zero();
+
+            while (1) {
+                        if (!need_resched()) {
+                                    while (!need_resched()) {
+                                                /* go into low thread
priority */
+                                                HMT_low();
+
+                                                /* go into low power mode
*/
+                                                local_irq_disable();
+                                                ctrl = mfspr(SPRN_CTRLF);
+                                                ctrl &= ~(CTRL_RUNLATCH |
CTRL_TE);
+                                                mtspr(SPRN_CTRLT, ctrl);
+                                                local_irq_enable();
+                                    }
+                                    /* restore thread prio */
+                                    HMT_medium();
+                        }
+
+                        ppc64_runlatch_on();
+                        preempt_enable_no_resched();
+                        schedule();
+                        preempt_disable();
+            }
+}
+
+static int __init cbe_find_pmd_mmio(int cpu, struct cbe_pervasive *p)
+{
+            struct device_node *node;
+            unsigned int *int_servers;
+            char *addr;
+            unsigned long real_address;
+            unsigned int size;
+
+            struct pmd_regs __iomem *pmd_mmio_area;
+            int hardid, thread;
+            int proplen;
+
+            pmd_mmio_area = NULL;
+            hardid = get_hard_smp_processor_id(cpu);
+            for (node = NULL; (node = of_find_node_by_type(node, "cpu"));)
{
+                        int_servers = (void *) get_property(node,
+
"ibm,ppc-interrupt-server#s", &proplen);
+                        if (!int_servers) {
+                                    printk(KERN_WARNING "CPU device misses
"
+
"ibm,ppc-interrupt-server#s property");
+                                    continue;
+                        }
+                        for (thread = 0; thread < proplen / sizeof (int);
thread++) {
+                                    if (hardid == int_servers[thread]) {
+                                                addr = get_property(node,
"pervasive", NULL);
+                                                goto found;
+                                    }
+                        }
+            }
+
+            printk(KERN_WARNING "%s: CPU %d not found\n", __FUNCTION__,
cpu);
+            return -EINVAL;
+
+found:
+            real_address = *(unsigned long*) addr;
+            addr += sizeof (unsigned long);
+            size = *(unsigned int*) addr;
+
+            pr_debug("pervasive area for CPU %d at %lx, size %x\n",
+                                    cpu, real_address, size);
+            p->regs = __ioremap(real_address, size, _PAGE_NO_CACHE);
+            p->thread = thread;
+            return 0;
+}
+
+void __init cell_pervasive_init(void)
+{
+            struct cbe_pervasive *p;
+            int cpu;
+            int ret;
+
+            if (!cpu_has_feature(CPU_FTR_PAUSE_ZERO))
+                        return;
+
+            for_each_cpu(cpu) {
+                        p = &cbe_pervasive[cpu];
+                        ret = cbe_find_pmd_mmio(cpu, p);
+                        if (ret)
+                                    return;
+            }
+
+            ppc_md.idle_loop = cbe_idle;
+}
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/pervasive.h
===================================================================
--- /dev/null
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/pervasive.h
@@ -0,0 +1,62 @@
+/*
+ * Cell Pervasive Monitor and Debug interface and HW structures
+ *
+ * (C) Copyright IBM Corporation 2005
+ *
+ * Authors: Maximino Aguilar (maguilar at us.ibm.com)
+ *          David J. Erb (djerb at us.ibm.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#ifndef PERVASIVE_H
+#define PERVASIVE_H
+
+struct pmd_regs {
+            u8 pad_0x0000_0x0800[0x0800 - 0x0000];
       /* 0x0000 */
+
+            /* Thermal Sensor Registers */
+            u64  ts_ctsr1;
                   /* 0x0800 */
+            u64  ts_ctsr2;
                   /* 0x0808 */
+            u64  ts_mtsr1;
                   /* 0x0810 */
+            u64  ts_mtsr2;
                   /* 0x0818 */
+            u64  ts_itr1;
                   /* 0x0820 */
+            u64  ts_itr2;
                   /* 0x0828 */
+            u64  ts_gitr;
                   /* 0x0830 */
+            u64  ts_isr;
                   /* 0x0838 */
+            u64  ts_imr;
                   /* 0x0840 */
+            u64  tm_cr1;
                   /* 0x0848 */
+            u64  tm_cr2;
                   /* 0x0850 */
+            u64  tm_simr;
                   /* 0x0858 */
+            u64  tm_tpr;
                   /* 0x0860 */
+            u64  tm_str1;
                   /* 0x0868 */
+            u64  tm_str2;
                   /* 0x0870 */
+            u64  tm_tsr;
                   /* 0x0878 */
+
+            /* Power Management */
+            u64  pm_control;
       /* 0x0880 */
+#define PMD_PAUSE_ZERO_CONTROL                        0x10000
+            u64  pm_status;
                   /* 0x0888 */
+
+            /* Time Base Register */
+            u64  tbr;
             /* 0x0890 */
+
+            u8   pad_0x0898_0x1000 [0x1000 - 0x0898];
 /* 0x0898 */
+};
+
+void __init cell_pervasive_init(void);
+
+#endif
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/setup.c
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/setup.c
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/setup.c
@@ -49,6 +49,7 @@

 #include "interrupt.h"
 #include "iommu.h"
+#include "pervasive.h"

 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -165,6 +166,7 @@ static void __init cell_setup_arch(void)
             init_pci_config_tokens();
             find_and_init_phbs();
             spider_init_IRQ();
+            cell_pervasive_init();
 #ifdef CONFIG_DUMMY_CONSOLE
             conswitchp = &dummy_con;
 #endif
Index: linux-2.6.15-rc/arch/powerpc/kernel/head_64.S
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/kernel/head_64.S
+++ linux-2.6.15-rc/arch/powerpc/kernel/head_64.S
@@ -401,7 +401,7 @@ label##_common:
                         \
             .globl __start_interrupts
 __start_interrupts:

-            STD_EXCEPTION_PSERIES(0x100, system_reset)
+            STD_EXCEPTION_PSERIES(0x100, system_reset_check)

             . = 0x200
 _machine_check_pSeries:
@@ -880,6 +880,28 @@ unrecov_fer:
             bl          .unrecoverable_exception
             b           1b

+/* This is a new system reset handler for the BE processor.
+ * SRR1 stores wake information that must be decoded to determine why
+ * the processor was at the system reset handler.
+ */
+
+            .align 7
+            .globl system_reset_check_common
+system_reset_check_common:
+BEGIN_FTR_SECTION
+            mr          r22,r12    /* r12 has SRR1 saved */
+            srwi        r22,r22,16
+            andi.             r22,r22,MSR_WAKEMASK
+            cmpwi             r22,MSR_WAKEEE
+            beq         hardware_interrupt_common
+            cmpwi             r22,MSR_WAKEDEC
+            beq         decrementer_common
+            cmpwi             r22,MSR_WAKEMT
+            bne         system_reset_common
+END_FTR_SECTION_IFSET(CPU_FTR_PAUSE_ZERO)
+            EXCEPTION_PROLOG_COMMON(0x100, PACA_EXGEN);
+            b           fast_exception_return
+
 /*
  * Here r13 points to the paca, r9 contains the saved CR,
  * SRR0 and SRR1 are saved in r11 and r12,
Index: linux-2.6.15-rc/include/asm-powerpc/cputable.h
===================================================================
--- linux-2.6.15-rc.orig/include/asm-powerpc/cputable.h
+++ linux-2.6.15-rc/include/asm-powerpc/cputable.h
@@ -106,6 +106,7 @@ extern void do_cpu_ftr_fixups(unsigned l
 #define CPU_FTR_LOCKLESS_TLBIE
ASM_CONST(0x0000040000000000)
 #define CPU_FTR_MMCRA_SIHV
ASM_CONST(0x0000080000000000)
 #define CPU_FTR_CI_LARGE_PAGE
ASM_CONST(0x0000100000000000)
+#define CPU_FTR_PAUSE_ZERO
ASM_CONST(0x0000200000000000)
 #else
 /* ensure on 32b processors the flags are available for compiling but
  * don't do anything */
@@ -305,7 +306,8 @@ enum {
                 CPU_FTR_MMCRA_SIHV,
             CPU_FTRS_CELL = CPU_FTR_SPLIT_ID_CACHE | CPU_FTR_USE_TB |
                 CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2 |
-                CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT,
+                CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT |
+                CPU_FTR_CTRL | CPU_FTR_PAUSE_ZERO,
             CPU_FTRS_COMPATIBLE = CPU_FTR_SPLIT_ID_CACHE | CPU_FTR_USE_TB
|
                 CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2,
 #endif
Index: linux-2.6.15-rc/include/asm-powerpc/reg.h
===================================================================
--- linux-2.6.15-rc.orig/include/asm-powerpc/reg.h
+++ linux-2.6.15-rc/include/asm-powerpc/reg.h
@@ -92,6 +92,15 @@
 #define MSR_RI                      __MASK(MSR_RI_LG)             /*
Recoverable Exception */
 #define MSR_LE                      __MASK(MSR_LE_LG)             /*
Little Endian */

+/* Wake Events */
+#define MSR_WAKEMASK          0x0038
+#define MSR_WAKERESET         0x0038
+#define MSR_WAKESYSERR        0x0030
+#define MSR_WAKEEE            0x0020
+#define MSR_WAKEMT            0x0028
+#define MSR_WAKEDEC           0x0018
+#define MSR_WAKETHERM         0x0010
+
 #ifdef CONFIG_PPC64
 #define MSR_                        MSR_ME | MSR_RI | MSR_IR | MSR_DR |
MSR_ISF
 #define MSR_KERNEL      MSR_ | MSR_SF | MSR_HV
@@ -145,6 +154,10 @@
 #define SPRN_CTR        0x009             /* Count Register */
 #define SPRN_CTRLF            0x088
 #define SPRN_CTRLT            0x098
+#define   CTRL_CT             0xc0000000        /* current thread */
+#define   CTRL_CT0            0x80000000        /* thread 0 */
+#define   CTRL_CT1            0x40000000        /* thread 1 */
+#define   CTRL_TE             0x00c00000        /* thread enable */
 #define   CTRL_RUNLATCH             0x1
 #define SPRN_DABR             0x3F5             /* Data Address Breakpoint
Register */
 #define   DABR_TRANSLATION          (1UL << 2)
@@ -257,11 +270,11 @@
 #define           SPRN_HID6         0x3F9             /* BE HID 6 */
 #define             HID6_LB         (0x0F<<12) /* Concurrent Large Page
Modes */
 #define             HID6_DLP        (1<<20)           /* Disable all large
page modes (4K only) */
-#define           SPRN_TSCR         0x399   /* Thread switch control on BE
*/
-#define           SPRN_TTR          0x39A   /* Thread switch timeout on BE
*/
-#define             TSCR_DEC_ENABLE             0x200000 /* Decrementer
Interrupt */
-#define             TSCR_EE_ENABLE        0x100000 /* External Interrupt
*/
-#define             TSCR_EE_BOOST                     0x080000 /* External
Interrupt Boost */
+#define           SPRN_TSC_CELL           0x399             /* Thread
switch control on Cell */
+#define             TSC_CELL_DEC_ENABLE_0             0x400000 /*
Decrementer Interrupt */
+#define             TSC_CELL_DEC_ENABLE_1             0x200000 /*
Decrementer Interrupt */
+#define             TSC_CELL_EE_ENABLE          0x100000 /* External
Interrupt */
+#define             TSC_CELL_EE_BOOST           0x080000 /* External
Interrupt Boost */
 #define           SPRN_TSC          0x3FD             /* Thread switch
control on others */
 #define           SPRN_TST          0x3FC             /* Thread switch
timeout on others */
 #if !defined(SPRN_IAC1) && !defined(SPRN_IAC2)
Index: linux-2.6.15-rc/arch/powerpc/kernel/cputable.c
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/kernel/cputable.c
+++ linux-2.6.15-rc/arch/powerpc/kernel/cputable.c
@@ -273,7 +273,7 @@ struct cpu_spec        cpu_specs[] = {
                         .oprofile_model                     =
&op_model_power4,
 #endif
             },
-            {           /* BE DD1.x */
+            {           /* Cell Broadband Engine */
                         .pvr_mask                     = 0xffff0000,
                         .pvr_value                    = 0x00700000,
                         .cpu_name                     = "Cell Broadband
Engine",
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