--- /dev/null
+/*
+ * Driver/API for AMD Geode Multi-Function General Purpose Timers (MFGPT)
+ *
+ * Copyright (C) 2006, Advanced Micro Devices, Inc.
+ * Copyright (C) 2007, Andres Salomon <dilinger@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book.
+ */
+
+/*
+ * We are using the 32Khz input clock - its the only one that has the
+ * ranges we find desirable. The following table lists the suitable
+ * divisors and the associated hz, minimum interval
+ * and the maximum interval:
+ *
+ * Divisor Hz Min Delta (S) Max Delta (S)
+ * 1 32000 .0005 2.048
+ * 2 16000 .001 4.096
+ * 4 8000 .002 8.192
+ * 8 4000 .004 16.384
+ * 16 2000 .008 32.768
+ * 32 1000 .016 65.536
+ * 64 500 .032 131.072
+ * 128 250 .064 262.144
+ * 256 125 .128 524.288
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <asm/geode.h>
+
+#define F_AVAIL 0x01
+
+static struct mfgpt_timer_t {
+ int flags;
+ struct module *owner;
+} mfgpt_timers[MFGPT_MAX_TIMERS];
+
+/* Selected from the table above */
+
+#define MFGPT_DIVISOR 16
+#define MFGPT_SCALE 4 /* divisor = 2^(scale) */
+#define MFGPT_HZ (32000 / MFGPT_DIVISOR)
+#define MFGPT_PERIODIC (MFGPT_HZ / HZ)
+
+/* Allow for disabling of MFGPTs */
+static int disable;
+static int __init mfgpt_disable(char *s)
+{
+ disable = 1;
+ return 1;
+}
+__setup("nomfgpt", mfgpt_disable);
+
+/*
+ * Check whether any MFGPTs are available for the kernel to use. In most
+ * cases, firmware that uses AMD's VSA code will claim all timers during
+ * bootup; we certainly don't want to take them if they're already in use.
+ * In other cases (such as with VSAless OpenFirmware), the system firmware
+ * leaves timers available for us to use.
+ */
+int __init geode_mfgpt_detect(void)
+{
+ int count = 0, i;
+ u16 val;
+
+ if (disable) {
+ printk(KERN_INFO "geode-mfgpt: Skipping MFGPT setup\n");
+ return 0;
+ }
+
+ for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
+ val = geode_mfgpt_read(i, MFGPT_REG_SETUP);
+ if (!(val & MFGPT_SETUP_SETUP)) {
+ mfgpt_timers[i].flags = F_AVAIL;
+ count++;
+ }
+ }
+
+ return count;
+}
+
+int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable)
+{
+ u32 msr, mask, value, dummy;
+ int shift = (cmp == MFGPT_CMP1) ? 0 : 8;
+
+ if (timer < 0 || timer >= MFGPT_MAX_TIMERS)
+ return -EIO;
+
+ /*
+ * The register maps for these are described in sections 6.17.1.x of
+ * the AMD Geode CS5536 Companion Device Data Book.
+ */
+ switch (event) {
+ case MFGPT_EVENT_RESET:
+ /*
+ * XXX: According to the docs, we cannot reset timers above
+ * 6; that is, resets for 7 and 8 will be ignored. Is this
+ * a problem? -dilinger
+ */
+ msr = MFGPT_NR_MSR;
+ mask = 1 << (timer + 24);
+ break;
+
+ case MFGPT_EVENT_NMI:
+ msr = MFGPT_NR_MSR;
+ mask = 1 << (timer + shift);
+ break;
+
+ case MFGPT_EVENT_IRQ:
+ msr = MFGPT_IRQ_MSR;
+ mask = 1 << (timer + shift);
+ break;
+
+ default:
+ return -EIO;
+ }
+
+ rdmsr(msr, value, dummy);
+
+ if (enable)
+ value |= mask;
+ else
+ value &= ~mask;
+
+ wrmsr(msr, value, dummy);
+ return 0;
+}
+
+int geode_mfgpt_set_irq(int timer, int cmp, int irq, int enable)
+{
+ u32 val, dummy;
+ int offset;
+
+ if (timer < 0 || timer >= MFGPT_MAX_TIMERS)
+ return -EIO;
+
+ if (geode_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable))
+ return -EIO;
+
+ rdmsr(MSR_PIC_ZSEL_LOW, val, dummy);
+
+ offset = (timer % 4) * 4;
+
+ val &= ~((0xF << offset) | (0xF << (offset + 16)));
+
+ if (enable) {
+ val |= (irq & 0x0F) << (offset);
+ val |= (irq & 0x0F) << (offset + 16);
+ }
+
+ wrmsr(MSR_PIC_ZSEL_LOW, val, dummy);
+ return 0;
+}
+
+static int mfgpt_get(int timer, struct module *owner)
+{
+ mfgpt_timers[timer].flags &= ~F_AVAIL;
+ mfgpt_timers[timer].owner = owner;
+ printk(KERN_INFO "geode-mfgpt: Registered timer %d\n", timer);
+ return timer;
+}
+
+int geode_mfgpt_alloc_timer(int timer, int domain, struct module *owner)
+{
+ int i;
+
+ if (!geode_get_dev_base(GEODE_DEV_MFGPT))
+ return -ENODEV;
+ if (timer >= MFGPT_MAX_TIMERS)
+ return -EIO;
+
+ if (timer < 0) {
+ /* Try to find an available timer */
+ for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
+ if (mfgpt_timers[i].flags & F_AVAIL)
+ return mfgpt_get(i, owner);
+
+ if (i == 5 && domain == MFGPT_DOMAIN_WORKING)
+ break;
+ }
+ } else {
+ /* If they requested a specific timer, try to honor that */
+ if (mfgpt_timers[timer].flags & F_AVAIL)
+ return mfgpt_get(timer, owner);
+ }
+
+ /* No timers available - too bad */
+ return -1;
+}
+
return (is_geode_gx() || is_geode_lx());
}
+/* MFGPTs */
+
+#define MFGPT_MAX_TIMERS 8
+#define MFGPT_TIMER_ANY -1
+
+#define MFGPT_DOMAIN_WORKING 1
+#define MFGPT_DOMAIN_STANDBY 2
+#define MFGPT_DOMAIN_ANY (MFGPT_DOMAIN_WORKING | MFGPT_DOMAIN_STANDBY)
+
+#define MFGPT_CMP1 0
+#define MFGPT_CMP2 1
+
+#define MFGPT_EVENT_IRQ 0
+#define MFGPT_EVENT_NMI 1
+#define MFGPT_EVENT_RESET 3
+
+#define MFGPT_REG_CMP1 0
+#define MFGPT_REG_CMP2 2
+#define MFGPT_REG_COUNTER 4
+#define MFGPT_REG_SETUP 6
+
+#define MFGPT_SETUP_CNTEN (1 << 15)
+#define MFGPT_SETUP_CMP2 (1 << 14)
+#define MFGPT_SETUP_CMP1 (1 << 13)
+#define MFGPT_SETUP_SETUP (1 << 12)
+#define MFGPT_SETUP_STOPEN (1 << 11)
+#define MFGPT_SETUP_EXTEN (1 << 10)
+#define MFGPT_SETUP_REVEN (1 << 5)
+#define MFGPT_SETUP_CLKSEL (1 << 4)
+
+static inline void geode_mfgpt_write(int timer, u16 reg, u16 value)
+{
+ u32 base = geode_get_dev_base(GEODE_DEV_MFGPT);
+ outw(value, base + reg + (timer * 8));
+}
+
+static inline u16 geode_mfgpt_read(int timer, u16 reg)
+{
+ u32 base = geode_get_dev_base(GEODE_DEV_MFGPT);
+ return inw(base + reg + (timer * 8));
+}
+
+extern int __init geode_mfgpt_detect(void);
+extern int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable);
+extern int geode_mfgpt_set_irq(int timer, int cmp, int irq, int enable);
+extern int geode_mfgpt_alloc_timer(int timer, int domain, struct module *owner);
+
+#define geode_mfgpt_setup_irq(t, c, i) geode_mfgpt_set_irq((t), (c), (i), 1)
+#define geode_mfgpt_release_irq(t, c, i) geode_mfgpt_set_irq((t), (c), (i), 0)
+
#endif
projects / users / hch / dma-mapping.git / commitdiff