diff options
Diffstat (limited to 'drivers/idle/i7300_idle.c')
| -rw-r--r-- | drivers/idle/i7300_idle.c | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/drivers/idle/i7300_idle.c b/drivers/idle/i7300_idle.c new file mode 100644 index 00000000000..fb176f6ef9f --- /dev/null +++ b/drivers/idle/i7300_idle.c @@ -0,0 +1,609 @@ +/* + * (C) Copyright 2008 Intel Corporation + * Authors: + * Andy Henroid <andrew.d.henroid@intel.com> + * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> + */ + +/* + * Save DIMM power on Intel 7300-based platforms when all CPUs/cores + * are idle, using the DIMM thermal throttling capability. + * + * This driver depends on the Intel integrated DMA controller (I/O AT). + * If the driver for I/O AT (drivers/dma/ioatdma*) is also enabled, + * this driver should work cooperatively. + */ + +/* #define DEBUG */ + +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/sched.h> +#include <linux/notifier.h> +#include <linux/cpumask.h> +#include <linux/ktime.h> +#include <linux/delay.h> +#include <linux/debugfs.h> +#include <linux/stop_machine.h> +#include <linux/i7300_idle.h> + +#include <asm/idle.h> + +#include "../dma/ioatdma_hw.h" +#include "../dma/ioatdma_registers.h" + +#define I7300_IDLE_DRIVER_VERSION "1.55" +#define I7300_PRINT "i7300_idle:" + +#define MAX_STOP_RETRIES 10 + +static int debug; +module_param_named(debug, debug, uint, 0644); +MODULE_PARM_DESC(debug, "Enable debug printks in this driver"); + +#define dprintk(fmt, arg...) \ + do { if (debug) printk(KERN_INFO I7300_PRINT fmt, ##arg); } while (0) + +/* + * Value to set THRTLOW to when initiating throttling + * 0 = No throttling + * 1 = Throttle when > 4 activations per eval window (Maximum throttling) + * 2 = Throttle when > 8 activations + * 168 = Throttle when > 672 activations (Minimum throttling) + */ +#define MAX_THROTTLE_LOW_LIMIT 168 +static uint throttle_low_limit = 1; +module_param_named(throttle_low_limit, throttle_low_limit, uint, 0644); +MODULE_PARM_DESC(throttle_low_limit, + "Value for THRTLOWLM activation field " + "(0 = disable throttle, 1 = Max throttle, 168 = Min throttle)"); + +/* + * simple invocation and duration statistics + */ +static unsigned long total_starts; +static unsigned long total_us; + +#ifdef DEBUG +static unsigned long past_skip; +#endif + +static struct pci_dev *fbd_dev; + +static spinlock_t i7300_idle_lock; +static int i7300_idle_active; + +static u8 i7300_idle_thrtctl_saved; +static u8 i7300_idle_thrtlow_saved; +static u32 i7300_idle_mc_saved; + +static cpumask_t idle_cpumask; +static ktime_t start_ktime; +static unsigned long avg_idle_us; + +static struct dentry *debugfs_dir; + +/* Begin: I/O AT Helper routines */ + +#define IOAT_CHANBASE(ioat_ctl, chan) (ioat_ctl + 0x80 + 0x80 * chan) +/* Snoop control (disable snoops when coherency is not important) */ +#define IOAT_DESC_SADDR_SNP_CTL (1UL << 1) +#define IOAT_DESC_DADDR_SNP_CTL (1UL << 2) + +static struct pci_dev *ioat_dev; +static struct ioat_dma_descriptor *ioat_desc; /* I/O AT desc & data (1 page) */ +static unsigned long ioat_desc_phys; +static u8 *ioat_iomap; /* I/O AT memory-mapped control regs (aka CB_BAR) */ +static u8 *ioat_chanbase; + +/* Start I/O AT memory copy */ +static int i7300_idle_ioat_start(void) +{ + u32 err; + /* Clear error (due to circular descriptor pointer) */ + err = readl(ioat_chanbase + IOAT_CHANERR_OFFSET); + if (err) + writel(err, ioat_chanbase + IOAT_CHANERR_OFFSET); + + writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET); + return 0; +} + +/* Stop I/O AT memory copy */ +static void i7300_idle_ioat_stop(void) +{ + int i; + u64 sts; + + for (i = 0; i < MAX_STOP_RETRIES; i++) { + writeb(IOAT_CHANCMD_RESET, + ioat_chanbase + IOAT1_CHANCMD_OFFSET); + + udelay(10); + + sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & + IOAT_CHANSTS_DMA_TRANSFER_STATUS; + + if (sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) + break; + + } + + if (i == MAX_STOP_RETRIES) { + dprintk("failed to stop I/O AT after %d retries\n", + MAX_STOP_RETRIES); + } +} + +/* Test I/O AT by copying 1024 byte from 2k to 1k */ +static int __init i7300_idle_ioat_selftest(u8 *ctl, + struct ioat_dma_descriptor *desc, unsigned long desc_phys) +{ + u64 chan_sts; + + memset(desc, 0, 2048); + memset((u8 *) desc + 2048, 0xab, 1024); + + desc[0].size = 1024; + desc[0].ctl = 0; + desc[0].src_addr = desc_phys + 2048; + desc[0].dst_addr = desc_phys + 1024; + desc[0].next = 0; + + writeb(IOAT_CHANCMD_RESET, ioat_chanbase + IOAT1_CHANCMD_OFFSET); + writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET); + + udelay(1000); + + chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & + IOAT_CHANSTS_DMA_TRANSFER_STATUS; + + if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE) { + /* Not complete, reset the channel */ + writeb(IOAT_CHANCMD_RESET, + ioat_chanbase + IOAT1_CHANCMD_OFFSET); + return -1; + } + + if (*(u32 *) ((u8 *) desc + 3068) != 0xabababab || + *(u32 *) ((u8 *) desc + 2044) != 0xabababab) { + dprintk("Data values src 0x%x, dest 0x%x, memset 0x%x\n", + *(u32 *) ((u8 *) desc + 2048), + *(u32 *) ((u8 *) desc + 1024), + *(u32 *) ((u8 *) desc + 3072)); + return -1; + } + return 0; +} + +static struct device dummy_dma_dev = { + .bus_id = "fallback device", + .coherent_dma_mask = DMA_64BIT_MASK, + .dma_mask = &dummy_dma_dev.coherent_dma_mask, +}; + +/* Setup and initialize I/O AT */ +/* This driver needs I/O AT as the throttling takes effect only when there is + * some memory activity. We use I/O AT to set up a dummy copy, while all CPUs + * go idle and memory is throttled. + */ +static int __init i7300_idle_ioat_init(void) +{ + u8 ver, chan_count, ioat_chan; + u16 chan_ctl; + + ioat_iomap = (u8 *) ioremap_nocache(pci_resource_start(ioat_dev, 0), + pci_resource_len(ioat_dev, 0)); + + if (!ioat_iomap) { + printk(KERN_ERR I7300_PRINT "failed to map I/O AT registers\n"); + goto err_ret; + } + + ver = readb(ioat_iomap + IOAT_VER_OFFSET); + if (ver != IOAT_VER_1_2) { + printk(KERN_ERR I7300_PRINT "unknown I/O AT version (%u.%u)\n", + ver >> 4, ver & 0xf); + goto err_unmap; + } + + chan_count = readb(ioat_iomap + IOAT_CHANCNT_OFFSET); + if (!chan_count) { + printk(KERN_ERR I7300_PRINT "unexpected # of I/O AT channels " + "(%u)\n", + chan_count); + goto err_unmap; + } + + ioat_chan = chan_count - 1; + ioat_chanbase = IOAT_CHANBASE(ioat_iomap, ioat_chan); + + chan_ctl = readw(ioat_chanbase + IOAT_CHANCTRL_OFFSET); + if (chan_ctl & IOAT_CHANCTRL_CHANNEL_IN_USE) { + printk(KERN_ERR I7300_PRINT "channel %d in use\n", ioat_chan); + goto err_unmap; + } + + writew(IOAT_CHANCTRL_CHANNEL_IN_USE, + ioat_chanbase + IOAT_CHANCTRL_OFFSET); + + ioat_desc = (struct ioat_dma_descriptor *)dma_alloc_coherent( + &dummy_dma_dev, 4096, + (dma_addr_t *)&ioat_desc_phys, GFP_KERNEL); + if (!ioat_desc) { + printk(KERN_ERR I7300_PRINT "failed to allocate I/O AT desc\n"); + goto err_mark_unused; + } + + writel(ioat_desc_phys & 0xffffffffUL, + ioat_chanbase + IOAT1_CHAINADDR_OFFSET_LOW); + writel(ioat_desc_phys >> 32, + ioat_chanbase + IOAT1_CHAINADDR_OFFSET_HIGH); + + if (i7300_idle_ioat_selftest(ioat_iomap, ioat_desc, ioat_desc_phys)) { + printk(KERN_ERR I7300_PRINT "I/O AT self-test failed\n"); + goto err_free; + } + + /* Setup circular I/O AT descriptor chain */ + ioat_desc[0].ctl = IOAT_DESC_SADDR_SNP_CTL | IOAT_DESC_DADDR_SNP_CTL; + ioat_desc[0].src_addr = ioat_desc_phys + 2048; + ioat_desc[0].dst_addr = ioat_desc_phys + 3072; + ioat_desc[0].size = 128; + ioat_desc[0].next = ioat_desc_phys + sizeof(struct ioat_dma_descriptor); + + ioat_desc[1].ctl = ioat_desc[0].ctl; + ioat_desc[1].src_addr = ioat_desc[0].src_addr; + ioat_desc[1].dst_addr = ioat_desc[0].dst_addr; + ioat_desc[1].size = ioat_desc[0].size; + ioat_desc[1].next = ioat_desc_phys; + + return 0; + +err_free: + dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0); +err_mark_unused: + writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET); +err_unmap: + iounmap(ioat_iomap); +err_ret: + return -ENODEV; +} + +/* Cleanup I/O AT */ +static void __exit i7300_idle_ioat_exit(void) +{ + int i; + u64 chan_sts; + + i7300_idle_ioat_stop(); + + /* Wait for a while for the channel to halt before releasing */ + for (i = 0; i < MAX_STOP_RETRIES; i++) { + writeb(IOAT_CHANCMD_RESET, + ioat_chanbase + IOAT1_CHANCMD_OFFSET); + + chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & + IOAT_CHANSTS_DMA_TRANSFER_STATUS; + + if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) { + writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET); + break; + } + udelay(1000); + } + + chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & + IOAT_CHANSTS_DMA_TRANSFER_STATUS; + + /* + * We tried to reset multiple times. If IO A/T channel is still active + * flag an error and return without cleanup. Memory leak is better + * than random corruption in that extreme error situation. + */ + if (chan_sts == IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) { + printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels." + " Not freeing resources\n"); + return; + } + + dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0); + iounmap(ioat_iomap); +} + +/* End: I/O AT Helper routines */ + +#define DIMM_THRTLOW 0x64 +#define DIMM_THRTCTL 0x67 +#define DIMM_THRTCTL_THRMHUNT (1UL << 0) +#define DIMM_MC 0x40 +#define DIMM_GTW_MODE (1UL << 17) +#define DIMM_GBLACT 0x60 + +/* + * Keep track of an exponential-decaying average of recent idle durations. + * The latest duration gets DURATION_WEIGHT_PCT percentage weight + * in this average, with the old average getting the remaining weight. + * + * High weights emphasize recent history, low weights include long history. + */ +#define DURATION_WEIGHT_PCT 55 + +/* + * When the decaying average of recent durations or the predicted duration + * of the next timer interrupt is shorter than duration_threshold, the + * driver will decline to throttle. + */ +#define DURATION_THRESHOLD_US 100 + + +/* Store DIMM thermal throttle configuration */ +static int i7300_idle_thrt_save(void) +{ + u32 new_mc_val; + u8 gblactlm; + + pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &i7300_idle_thrtctl_saved); + pci_read_config_byte(fbd_dev, DIMM_THRTLOW, &i7300_idle_thrtlow_saved); + pci_read_config_dword(fbd_dev, DIMM_MC, &i7300_idle_mc_saved); + /* + * Make sure we have Global Throttling Window Mode set to have a + * "short" window. This (mostly) works around an issue where + * throttling persists until the end of the global throttling window + * size. On the tested system, this was resulting in a maximum of + * 64 ms to exit throttling (average 32 ms). The actual numbers + * depends on system frequencies. Setting the short window reduces + * this by a factor of 4096. + * + * We will only do this only if the system is set for + * unlimited-activations while in open-loop throttling (i.e., when + * Global Activation Throttle Limit is zero). + */ + pci_read_config_byte(fbd_dev, DIMM_GBLACT, &gblactlm); + dprintk("thrtctl_saved = 0x%02x, thrtlow_saved = 0x%02x\n", + i7300_idle_thrtctl_saved, + i7300_idle_thrtlow_saved); + dprintk("mc_saved = 0x%08x, gblactlm = 0x%02x\n", + i7300_idle_mc_saved, + gblactlm); + if (gblactlm == 0) { + new_mc_val = i7300_idle_mc_saved | DIMM_GTW_MODE; + pci_write_config_dword(fbd_dev, DIMM_MC, new_mc_val); + return 0; + } else { + dprintk("could not set GTW_MODE = 1 (OLTT enabled)\n"); + return -ENODEV; + } +} + +/* Restore DIMM thermal throttle configuration */ +static void i7300_idle_thrt_restore(void) +{ + pci_write_config_dword(fbd_dev, DIMM_MC, i7300_idle_mc_saved); + pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved); + pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved); +} + +/* Enable DIMM thermal throttling */ +static void i7300_idle_start(void) +{ + u8 new_ctl; + u8 limit; + + new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT; + pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl); + + limit = throttle_low_limit; + if (unlikely(limit > MAX_THROTTLE_LOW_LIMIT)) + limit = MAX_THROTTLE_LOW_LIMIT; + + pci_write_config_byte(fbd_dev, DIMM_THRTLOW, limit); + + new_ctl = i7300_idle_thrtctl_saved | DIMM_THRTCTL_THRMHUNT; + pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl); +} + +/* Disable DIMM thermal throttling */ +static void i7300_idle_stop(void) +{ + u8 new_ctl; + u8 got_ctl; + + new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT; + pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl); + + pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved); + pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved); + pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &got_ctl); + WARN_ON_ONCE(got_ctl != i7300_idle_thrtctl_saved); +} + + +/* + * i7300_avg_duration_check() + * return 0 if the decaying average of recent idle durations is + * more than DURATION_THRESHOLD_US + */ +static int i7300_avg_duration_check(void) +{ + if (avg_idle_us >= DURATION_THRESHOLD_US) + return 0; + +#ifdef DEBUG + past_skip++; +#endif + return 1; +} + +/* Idle notifier to look at idle CPUs */ +static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + unsigned long flags; + ktime_t now_ktime; + static ktime_t idle_begin_time; + static int time_init = 1; + + if (!throttle_low_limit) + return 0; + + if (unlikely(time_init)) { + time_init = 0; + idle_begin_time = ktime_get(); + } + + spin_lock_irqsave(&i7300_idle_lock, flags); + if (val == IDLE_START) { + + cpu_set(smp_processor_id(), idle_cpumask); + + if (cpus_weight(idle_cpumask) != num_online_cpus()) + goto end; + + now_ktime = ktime_get(); + idle_begin_time = now_ktime; + + if (i7300_avg_duration_check()) + goto end; + + i7300_idle_active = 1; + total_starts++; + start_ktime = now_ktime; + + i7300_idle_start(); + i7300_idle_ioat_start(); + + } else if (val == IDLE_END) { + cpu_clear(smp_processor_id(), idle_cpumask); + if (cpus_weight(idle_cpumask) == (num_online_cpus() - 1)) { + /* First CPU coming out of idle */ + u64 idle_duration_us; + + now_ktime = ktime_get(); + + idle_duration_us = ktime_to_us(ktime_sub + (now_ktime, idle_begin_time)); + + avg_idle_us = + ((100 - DURATION_WEIGHT_PCT) * avg_idle_us + + DURATION_WEIGHT_PCT * idle_duration_us) / 100; + + if (i7300_idle_active) { + ktime_t idle_ktime; + + idle_ktime = ktime_sub(now_ktime, start_ktime); + total_us += ktime_to_us(idle_ktime); + + i7300_idle_ioat_stop(); + i7300_idle_stop(); + i7300_idle_active = 0; + } + } + } +end: + spin_unlock_irqrestore(&i7300_idle_lock, flags); + return 0; +} + +static struct notifier_block i7300_idle_nb = { + .notifier_call = i7300_idle_notifier, +}; + +MODULE_DEVICE_TABLE(pci, pci_tbl); + +int stats_open_generic(struct inode *inode, struct file *fp) +{ + fp->private_data = inode->i_private; + return 0; +} + +static ssize_t stats_read_ul(struct file *fp, char __user *ubuf, size_t count, + loff_t *off) +{ + unsigned long *p = fp->private_data; + char buf[32]; + int len; + + len = snprintf(buf, 32, "%lu\n", *p); + return simple_read_from_buffer(ubuf, count, off, buf, len); +} + +static const struct file_operations idle_fops = { + .open = stats_open_generic, + .read = stats_read_ul, +}; + +struct debugfs_file_info { + void *ptr; + char name[32]; + struct dentry *file; +} debugfs_file_list[] = { + {&total_starts, "total_starts", NULL}, + {&total_us, "total_us", NULL}, +#ifdef DEBUG + {&past_skip, "past_skip", NULL}, +#endif + {NULL, "", NULL} + }; + +static int __init i7300_idle_init(void) +{ + spin_lock_init(&i7300_idle_lock); + cpus_clear(idle_cpumask); + total_us = 0; + + if (i7300_idle_platform_probe(&fbd_dev, &ioat_dev)) + return -ENODEV; + + if (i7300_idle_thrt_save()) + return -ENODEV; + + if (i7300_idle_ioat_init()) + return -ENODEV; + + debugfs_dir = debugfs_create_dir("i7300_idle", NULL); + if (debugfs_dir) { + int i = 0; + + while (debugfs_file_list[i].ptr != NULL) { + debugfs_file_list[i].file = debugfs_create_file( + debugfs_file_list[i].name, + S_IRUSR, + debugfs_dir, + debugfs_file_list[i].ptr, + &idle_fops); + i++; + } + } + + idle_notifier_register(&i7300_idle_nb); + + printk(KERN_INFO "i7300_idle: loaded v%s\n", I7300_IDLE_DRIVER_VERSION); + return 0; +} + +static void __exit i7300_idle_exit(void) +{ + idle_notifier_unregister(&i7300_idle_nb); + + if (debugfs_dir) { + int i = 0; + + while (debugfs_file_list[i].file != NULL) { + debugfs_remove(debugfs_file_list[i].file); + i++; + } + + debugfs_remove(debugfs_dir); + } + i7300_idle_thrt_restore(); + i7300_idle_ioat_exit(); +} + +module_init(i7300_idle_init); +module_exit(i7300_idle_exit); + +MODULE_AUTHOR("Andy Henroid <andrew.d.henroid@intel.com>"); +MODULE_DESCRIPTION("Intel Chipset DIMM Idle Power Saving Driver v" + I7300_IDLE_DRIVER_VERSION); +MODULE_LICENSE("GPL"); |