/*
* RackMac vu-meter driver
*
* (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
* <benh@kernel.crashing.org>
*
* Released under the term of the GNU GPL v2.
*
* Support the CPU-meter LEDs of the Xserve G5
*
* TODO: Implement PWM to do variable intensity and provide userland
* interface for fun. Also, the CPU-meter could be made nicer by being
* a bit less "immediate" but giving instead a more average load over
* time. Patches welcome :-)
*
*/
#undef DEBUG
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/kernel_stat.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/dbdma.h>
#include <asm/macio.h>
#include <asm/keylargo.h>
/* Number of samples in a sample buffer */
#define SAMPLE_COUNT 256
/* CPU meter sampling rate in ms */
#define CPU_SAMPLING_RATE 250
struct rackmeter_dma {
struct dbdma_cmd cmd[4] ____cacheline_aligned;
u32 mark ____cacheline_aligned;
u32 buf1[SAMPLE_COUNT] ____cacheline_aligned;
u32 buf2[SAMPLE_COUNT] ____cacheline_aligned;
} ____cacheline_aligned;
struct rackmeter_cpu {
struct delayed_work sniffer;
struct rackmeter *rm;
u64 prev_wall;
u64 prev_idle;
int zero;
} ____cacheline_aligned;
struct rackmeter {
struct macio_dev *mdev;
unsigned int irq;
struct device_node *i2s;
u8 *ubuf;
struct dbdma_regs __iomem *dma_regs;
void __iomem *i2s_regs;
dma_addr_t dma_buf_p;
struct rackmeter_dma *dma_buf_v;
int stale_irq;
struct rackmeter_cpu cpu[2];
int paused;
struct mutex sem;
};
/* To be set as a tunable */
static int rackmeter_ignore_nice;
/* This GPIO is whacked by the OS X driver when initializing */
#define RACKMETER_MAGIC_GPIO 0x78
/* This is copied from cpufreq_ondemand, maybe we should put it in
* a common header somewhere
*/
static inline u64 get_cpu_idle_time(unsigned int cpu)
{
u64 retval;
retval = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE] +
kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
if (rackmeter_ignore_nice)
retval += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
return retval;
}
static void rackmeter_setup_i2s(struct rackmeter *rm)
{
struct macio_chip *macio = rm->mdev->bus->chip;
/* First whack magic GPIO */
pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);
/* Call feature code to enable the sound channel and the proper
* clock sources
*/
pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);
/* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now.
* This is a bit racy, thus we should add new platform functions to
* handle that. snd-aoa needs that too
*/
MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
(void)MACIO_IN32(KEYLARGO_FCR1);
udelay(10);
/* Then setup i2s. For now, we use the same magic value that
* the OS X driver seems to use. We might want to play around
* with the clock divisors later
*/
out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
(void)in_le32(rm->i2s_regs + 0x10);
udelay(10);
/* Fully restart i2s*/
MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE |
KL1_I2S0_CLK_ENABLE_BIT);
(void)MACIO_IN32(KEYLARGO_FCR1);
udelay(10);
}
static void rackmeter_set_default_pattern(struct rackmeter *rm)
{
int i;
for (i = 0; i < 16; i++) {
if (i < 8)
rm->ubuf[i] = (i & 1) * 255;
else
rm->ubuf[i] = ((~i) & 1) * 255;
}
}
static void rackmeter_do_pause(struct rackmeter *rm, int pause)
{
struct rackmeter_dma *rdma = rm->dma_buf_v;
pr_debug("rackmeter: %s\n", pause ? "paused" : "started");
rm->paused = pause;
if (pause) {
DBDMA_DO_STOP(rm->dma_regs);
return;
}
memset(rdma->buf1, 0, sizeof(rdma->buf1));
memset(rdma->buf2, 0, sizeof(rdma->buf2));
rm->dma_buf_v->mark = 0;
mb();
out_le32(&rm->dma_regs->cmdptr_hi, 0);
out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p);
out_le32(&rm->dma_regs->control, (RUN << 16) | RUN);
}
static void rackmeter_setup_dbdma(struct rackmeter *rm)
{
struct rackmeter_dma *db = rm->dma_buf_v;
struct dbdma_cmd *cmd = db->cmd;
/* Make sure dbdma is reset */
DBDMA_DO_RESET(rm->dma_regs);
pr_debug("rackmeter: mark offset=0x%zx\n",
offsetof(struct rackmeter_dma, mark));
pr_debug("rackmeter: buf1 offset=0x%zx\n",
offsetof(struct rackmeter_dma, buf1));
pr_debug("rackmeter: buf2 offset=0x%zx\n",
offsetof(struct rackmeter_dma, buf2));
/* Prepare 4 dbdma commands for the 2 buffers */
memset(cmd, 0, 4 * sizeof(struct dbdma_cmd));
cmd->req_count = cpu_to_le16(4);
cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
offsetof(struct rackmeter_dma, mark));
cmd->cmd_dep = cpu_to_le32(0x02000000);
cmd++;
cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
cmd->command = cpu_to_le16(OUTPUT_MORE);
cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
offsetof(struct rackmeter_dma, buf1));
cmd++;
cmd->req_count = cpu_to_le16(4);
cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
offsetof(struct rackmeter_dma, mark));
cmd->cmd_dep = cpu_to_le32(0x01000000);
cmd++;
cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS);
cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
offsetof(struct rackmeter_dma, buf2));
cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p);
rackmeter_do_pause(rm, 0);
}
static void rackmeter_do_timer(struct work_struct *work)
{
struct rackmeter_cpu *rcpu =
container_of(work, struct rackmeter_cpu, sniffer.work);
struct rackmeter *rm = rcpu->rm;
unsigned int cpu = smp_processor_id();
u64 cur_nsecs, total_idle_nsecs;
u64 total_nsecs, idle_nsecs;
int i, offset, load, cumm, pause;
cur_nsecs = jiffies64_to_nsecs(get_jiffies_64());
total_nsecs = cur_nsecs - rcpu->prev_wall;
rcpu->prev_wall = cur_nsecs;
total_idle_nsecs = get_cpu_idle_time(cpu);
idle_nsecs = total_idle_nsecs - rcpu->prev_idle;
idle_nsecs = min(idle_nsecs, total_nsecs);
rcpu->prev_idle = total_idle_nsecs;
/* We do a very dumb calculation to update the LEDs for now,
* we'll do better once we have actual PWM implemented
*/
load = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs);
offset = cpu << 3;
cumm = 0;
for (i = 0; i < 8; i++) {
u8 ub = (load > i) ? 0xff : 0;
rm->ubuf[i + offset] = ub;
cumm |= ub;
}
rcpu->zero = (cumm == 0);
/* Now check if LEDs are all 0, we can stop DMA */
pause = (rm->cpu[0].zero && rm->cpu[1].zero);
if (pause != rm->paused) {
mutex_lock(&rm->sem);
pause = (rm->cpu[0].zero && rm->cpu[1].zero);
rackmeter_do_pause(rm, pause);
mutex_unlock(&rm->sem);
}
schedule_delayed_work_on(cpu, &rcpu->sniffer,
msecs_to_jiffies(CPU_SAMPLING_RATE));
}
static void rackmeter_init_cpu_sniffer(struct rackmeter *rm)
{
unsigned int cpu;
/* This driver works only with 1 or 2 CPUs numbered 0 and 1,
* but that's really all we have on Apple Xserve. It doesn't
* play very nice with CPU hotplug neither but we don't do that
* on those machines yet
*/
rm->cpu[0].rm = rm;
INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer);
rm->cpu[1].rm = rm;
INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer);
for_each_online_cpu(cpu) {
struct rackmeter_cpu *rcpu;
if (cpu > 1)
continue;
rcpu = &rm->cpu[cpu];
rcpu->prev_idle = get_cpu_idle_time(cpu);
rcpu->prev_wall = jiffies64_to_nsecs(get_jiffies_64());
schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
msecs_to_jiffies(CPU_SAMPLING_RATE));
}
}
static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
{
cancel_delayed_work_sync(&rm->cpu[0].sniffer);
cancel_delayed_work_sync(&rm->cpu[1].sniffer);
}
static int rackmeter_setup(struct rackmeter *rm)
{
pr_debug("rackmeter: setting up i2s..\n");
rackmeter_setup_i2s(rm);
pr_debug("rackmeter: setting up default pattern..\n");
rackmeter_set_default_pattern(rm);
pr_debug("rackmeter: setting up dbdma..\n");
rackmeter_setup_dbdma(rm);
pr_debug("rackmeter: start CPU measurements..\n");
rackmeter_init_cpu_sniffer(rm);
printk(KERN_INFO "RackMeter initialized\n");
return 0;
}
/* XXX FIXME: No PWM yet, this is 0/1 */
static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index)
{
int led;
u32 sample = 0;
for (led = 0; led < 16; led++) {
sample >>= 1;
sample |= ((rm->ubuf[led] >= 0x80) << 15);
}
return (sample << 17) | (sample >> 15);
}
static irqreturn_t rackmeter_irq(int irq, void *arg)
{
struct rackmeter *rm = arg;
struct rackmeter_dma *db = rm->dma_buf_v;
unsigned int mark, i;
u32 *buf;
/* Flush PCI buffers with an MMIO read. Maybe we could actually
* check the status one day ... in case things go wrong, though
* this never happened to me
*/
(void)in_le32(&rm->dma_regs->status);
/* Make sure the CPU gets us in order */
rmb();
/* Read mark */
mark = db->mark;
if (mark != 1 && mark != 2) {
printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n",
mark);
/* We allow for 3 errors like that (stale DBDMA irqs) */
if (++rm->stale_irq > 3) {
printk(KERN_ERR "rackmeter: Too many errors,"
" stopping DMA\n");
DBDMA_DO_RESET(rm->dma_regs);
}
return IRQ_HANDLED;
}
/* Next buffer we need to fill is mark value */
buf = mark == 1 ? db->buf1 : db->buf2;
/* Fill it now. This routine converts the 8 bits depth sample array
* into the PWM bitmap for each LED.
*/
for (i = 0; i < SAMPLE_COUNT; i++)
buf[i] = rackmeter_calc_sample(rm, i);
return IRQ_HANDLED;
}
static int rackmeter_probe(struct macio_dev* mdev,
const struct of_device_id *match)
{
struct device_node *i2s = NULL, *np = NULL;
struct rackmeter *rm = NULL;
struct resource ri2s, rdma;
int rc = -ENODEV;
pr_debug("rackmeter_probe()\n");
/* Get i2s-a node */
while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL)
if (strcmp(i2s->name, "i2s-a") == 0)
break;
if (i2s == NULL) {
pr_debug(" i2s-a child not found\n");
goto bail;
}
/* Get lightshow or virtual sound */
while ((np = of_get_next_child(i2s, np)) != NULL) {
if (strcmp(np->name, "lightshow") == 0)
break;
if ((strcmp(np->name, "sound") == 0) &&
of_get_property(np, "virtual", NULL) != NULL)
break;
}
if (np == NULL) {
pr_debug(" lightshow or sound+virtual child not found\n");
goto bail;
}
/* Create and initialize our instance data */
rm = kzalloc(sizeof(*rm), GFP_KERNEL);
if (rm == NULL) {
printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
rc = -ENOMEM;
goto bail_release;
}
rm->mdev = mdev;
rm->i2s = i2s;
mutex_init(&rm->sem);
dev_set_drvdata(&mdev->ofdev.dev, rm);
/* Check resources availability. We need at least resource 0 and 1 */
#if 0 /* Use that when i2s-a is finally an mdev per-se */
if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) {
printk(KERN_ERR
"rackmeter: found match but lacks resources: %pOF"
" (%d resources, %d interrupts)\n",
mdev->ofdev.dev.of_node);
rc = -ENXIO;
goto bail_free;
}
if (macio_request_resources(mdev, "rackmeter")) {
printk(KERN_ERR
"rackmeter: failed to request resources: %pOF\n",
mdev->ofdev.dev.of_node);
rc = -EBUSY;
goto bail_free;
}
rm->irq = macio_irq(mdev, 1);
#else
rm->irq = irq_of_parse_and_map(i2s, 1);
if (!rm->irq ||
of_address_to_resource(i2s, 0, &ri2s) ||
of_address_to_resource(i2s, 1, &rdma)) {
printk(KERN_ERR
"rackmeter: found match but lacks resources: %pOF",
mdev->ofdev.dev.of_node);
rc = -ENXIO;
goto bail_free;
}
#endif
pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start);
pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start);
pr_debug(" irq %d\n", rm->irq);
rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
if (rm->ubuf == NULL) {
printk(KERN_ERR
"rackmeter: failed to allocate samples page !\n");
rc = -ENOMEM;
goto bail_release;
}
rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
sizeof(struct rackmeter_dma),
&rm->dma_buf_p, GFP_KERNEL);
if (rm->dma_buf_v == NULL) {
printk(KERN_ERR
"rackmeter: failed to allocate dma buffer !\n");
rc = -ENOMEM;
goto bail_free_samples;
}
#if 0
rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
#else
rm->i2s_regs = ioremap(ri2s.start, 0x1000);
#endif
if (rm->i2s_regs == NULL) {
printk(KERN_ERR
"rackmeter: failed to map i2s registers !\n");
rc = -ENXIO;
goto bail_free_dma;
}
#if 0
rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
#else
rm->dma_regs = ioremap(rdma.start, 0x100);
#endif
if (rm->dma_regs == NULL) {
printk(KERN_ERR
"rackmeter: failed to map dma registers !\n");
rc = -ENXIO;
goto bail_unmap_i2s;
}
rc = rackmeter_setup(rm);
if (rc) {
printk(KERN_ERR
"rackmeter: failed to initialize !\n");
rc = -ENXIO;
goto bail_unmap_dma;
}
rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
if (rc != 0) {
printk(KERN_ERR
"rackmeter: failed to request interrupt !\n");
goto bail_stop_dma;
}
of_node_put(np);
return 0;
bail_stop_dma:
DBDMA_DO_RESET(rm->dma_regs);
bail_unmap_dma:
iounmap(rm->dma_regs);
bail_unmap_i2s:
iounmap(rm->i2s_regs);
bail_free_dma:
dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
sizeof(struct rackmeter_dma),
rm->dma_buf_v, rm->dma_buf_p);
bail_free_samples:
free_page((unsigned long)rm->ubuf);
bail_release:
#if 0
macio_release_resources(mdev);
#endif
bail_free:
kfree(rm);
bail:
of_node_put(i2s);
of_node_put(np);
dev_set_drvdata(&mdev->ofdev.dev, NULL);
return rc;
}
static int rackmeter_remove(struct macio_dev* mdev)
{
struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
/* Stop CPU sniffer timer & work queues */
rackmeter_stop_cpu_sniffer(rm);
/* Clear reference to private data */
dev_set_drvdata(&mdev->ofdev.dev, NULL);
/* Stop/reset dbdma */
DBDMA_DO_RESET(rm->dma_regs);
/* Release the IRQ */
free_irq(rm->irq, rm);
/* Unmap registers */
iounmap(rm->dma_regs);
iounmap(rm->i2s_regs);
/* Free DMA */
dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
sizeof(struct rackmeter_dma),
rm->dma_buf_v, rm->dma_buf_p);
/* Free samples */
free_page((unsigned long)rm->ubuf);
#if 0
/* Release resources */
macio_release_resources(mdev);
#endif
/* Get rid of me */
kfree(rm);
return 0;
}
static int rackmeter_shutdown(struct macio_dev* mdev)
{
struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
if (rm == NULL)
return -ENODEV;
/* Stop CPU sniffer timer & work queues */
rackmeter_stop_cpu_sniffer(rm);
/* Stop/reset dbdma */
DBDMA_DO_RESET(rm->dma_regs);
return 0;
}
static const struct of_device_id rackmeter_match[] = {
{ .name = "i2s" },
{ }
};
MODULE_DEVICE_TABLE(of, rackmeter_match);
static struct macio_driver rackmeter_driver = {
.driver = {
.name = "rackmeter",
.owner = THIS_MODULE,
.of_match_table = rackmeter_match,
},
.probe = rackmeter_probe,
.remove = rackmeter_remove,
.shutdown = rackmeter_shutdown,
};
static int __init rackmeter_init(void)
{
pr_debug("rackmeter_init()\n");
return macio_register_driver(&rackmeter_driver);
}
static void __exit rackmeter_exit(void)
{
pr_debug("rackmeter_exit()\n");
macio_unregister_driver(&rackmeter_driver);
}
module_init(rackmeter_init);
module_exit(rackmeter_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
