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/*
* (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/ioat/hw.h"
#include "../dma/ioat/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");
static int forceload;
module_param_named(forceload, forceload, uint, 0644);
MODULE_PARM_DESC(debug, "Enable driver testing on unvalidated i5000");
#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_var_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_STATUS;
if (sts != IOAT_CHANSTS_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_STATUS;
if (chan_sts != IOAT_CHANSTS_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 = {
.init_name = "fallback device",
.coherent_dma_mask = DMA_BIT_MASK(64),
.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
|