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-rw-r--r--arch/sh/boards/mach-dreamcast/Makefile6
-rw-r--r--arch/sh/boards/mach-dreamcast/irq.c166
-rw-r--r--arch/sh/boards/mach-dreamcast/rtc.c81
-rw-r--r--arch/sh/boards/mach-dreamcast/setup.c41
4 files changed, 294 insertions, 0 deletions
diff --git a/arch/sh/boards/mach-dreamcast/Makefile b/arch/sh/boards/mach-dreamcast/Makefile
new file mode 100644
index 00000000000..7b97546c7e5
--- /dev/null
+++ b/arch/sh/boards/mach-dreamcast/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for the Sega Dreamcast specific parts of the kernel
+#
+
+obj-y := setup.o irq.o rtc.o
+
diff --git a/arch/sh/boards/mach-dreamcast/irq.c b/arch/sh/boards/mach-dreamcast/irq.c
new file mode 100644
index 00000000000..f63d323f411
--- /dev/null
+++ b/arch/sh/boards/mach-dreamcast/irq.c
@@ -0,0 +1,166 @@
+/*
+ * arch/sh/boards/dreamcast/irq.c
+ *
+ * Holly IRQ support for the Sega Dreamcast.
+ *
+ * Copyright (c) 2001, 2002 M. R. Brown <mrbrown@0xd6.org>
+ *
+ * This file is part of the LinuxDC project (www.linuxdc.org)
+ * Released under the terms of the GNU GPL v2.0
+ */
+
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <asm/irq.h>
+#include <mach/sysasic.h>
+
+/*
+ * Dreamcast System ASIC Hardware Events -
+ *
+ * The Dreamcast's System ASIC (a.k.a. Holly) is responsible for receiving
+ * hardware events from system peripherals and triggering an SH7750 IRQ.
+ * Hardware events can trigger IRQs 13, 11, or 9 depending on which bits are
+ * set in the Event Mask Registers (EMRs). When a hardware event is
+ * triggered, its corresponding bit in the Event Status Registers (ESRs)
+ * is set, and that bit should be rewritten to the ESR to acknowledge that
+ * event.
+ *
+ * There are three 32-bit ESRs located at 0xa05f6900 - 0xa05f6908. Event
+ * types can be found in arch/sh/include/mach-dreamcast/mach/sysasic.h.
+ * There are three groups of EMRs that parallel the ESRs. Each EMR group
+ * corresponds to an IRQ, so 0xa05f6910 - 0xa05f6918 triggers IRQ 13,
+ * 0xa05f6920 - 0xa05f6928 triggers IRQ 11, and 0xa05f6930 - 0xa05f6938
+ * triggers IRQ 9.
+ *
+ * In the kernel, these events are mapped to virtual IRQs so that drivers can
+ * respond to them as they would a normal interrupt. In order to keep this
+ * mapping simple, the events are mapped as:
+ *
+ * 6900/6910 - Events 0-31, IRQ 13
+ * 6904/6924 - Events 32-63, IRQ 11
+ * 6908/6938 - Events 64-95, IRQ 9
+ *
+ */
+
+#define ESR_BASE 0x005f6900 /* Base event status register */
+#define EMR_BASE 0x005f6910 /* Base event mask register */
+
+/*
+ * Helps us determine the EMR group that this event belongs to: 0 = 0x6910,
+ * 1 = 0x6920, 2 = 0x6930; also determine the event offset.
+ */
+#define LEVEL(event) (((event) - HW_EVENT_IRQ_BASE) / 32)
+
+/* Return the hardware event's bit position within the EMR/ESR */
+#define EVENT_BIT(event) (((event) - HW_EVENT_IRQ_BASE) & 31)
+
+/*
+ * For each of these *_irq routines, the IRQ passed in is the virtual IRQ
+ * (logically mapped to the corresponding bit for the hardware event).
+ */
+
+/* Disable the hardware event by masking its bit in its EMR */
+static inline void disable_systemasic_irq(struct irq_data *data)
+{
+ unsigned int irq = data->irq;
+ __u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2);
+ __u32 mask;
+
+ mask = inl(emr);
+ mask &= ~(1 << EVENT_BIT(irq));
+ outl(mask, emr);
+}
+
+/* Enable the hardware event by setting its bit in its EMR */
+static inline void enable_systemasic_irq(struct irq_data *data)
+{
+ unsigned int irq = data->irq;
+ __u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2);
+ __u32 mask;
+
+ mask = inl(emr);
+ mask |= (1 << EVENT_BIT(irq));
+ outl(mask, emr);
+}
+
+/* Acknowledge a hardware event by writing its bit back to its ESR */
+static void mask_ack_systemasic_irq(struct irq_data *data)
+{
+ unsigned int irq = data->irq;
+ __u32 esr = ESR_BASE + (LEVEL(irq) << 2);
+ disable_systemasic_irq(data);
+ outl((1 << EVENT_BIT(irq)), esr);
+}
+
+struct irq_chip systemasic_int = {
+ .name = "System ASIC",
+ .irq_mask = disable_systemasic_irq,
+ .irq_mask_ack = mask_ack_systemasic_irq,
+ .irq_unmask = enable_systemasic_irq,
+};
+
+/*
+ * Map the hardware event indicated by the processor IRQ to a virtual IRQ.
+ */
+int systemasic_irq_demux(int irq)
+{
+ __u32 emr, esr, status, level;
+ __u32 j, bit;
+
+ switch (irq) {
+ case 13:
+ level = 0;
+ break;
+ case 11:
+ level = 1;
+ break;
+ case 9:
+ level = 2;
+ break;
+ default:
+ return irq;
+ }
+ emr = EMR_BASE + (level << 4) + (level << 2);
+ esr = ESR_BASE + (level << 2);
+
+ /* Mask the ESR to filter any spurious, unwanted interrupts */
+ status = inl(esr);
+ status &= inl(emr);
+
+ /* Now scan and find the first set bit as the event to map */
+ for (bit = 1, j = 0; j < 32; bit <<= 1, j++) {
+ if (status & bit) {
+ irq = HW_EVENT_IRQ_BASE + j + (level << 5);
+ return irq;
+ }
+ }
+
+ /* Not reached */
+ return irq;
+}
+
+void systemasic_irq_init(void)
+{
+ int i, nid = cpu_to_node(boot_cpu_data);
+
+ /* Assign all virtual IRQs to the System ASIC int. handler */
+ for (i = HW_EVENT_IRQ_BASE; i < HW_EVENT_IRQ_MAX; i++) {
+ unsigned int irq;
+
+ irq = create_irq_nr(i, nid);
+ if (unlikely(irq == 0)) {
+ pr_err("%s: failed hooking irq %d for systemasic\n",
+ __func__, i);
+ return;
+ }
+
+ if (unlikely(irq != i)) {
+ pr_err("%s: got irq %d but wanted %d, bailing.\n",
+ __func__, irq, i);
+ destroy_irq(irq);
+ return;
+ }
+
+ irq_set_chip_and_handler(i, &systemasic_int, handle_level_irq);
+ }
+}
diff --git a/arch/sh/boards/mach-dreamcast/rtc.c b/arch/sh/boards/mach-dreamcast/rtc.c
new file mode 100644
index 00000000000..061d65714fc
--- /dev/null
+++ b/arch/sh/boards/mach-dreamcast/rtc.c
@@ -0,0 +1,81 @@
+/*
+ * arch/sh/boards/dreamcast/rtc.c
+ *
+ * Dreamcast AICA RTC routines.
+ *
+ * Copyright (c) 2001, 2002 M. R. Brown <mrbrown@0xd6.org>
+ * Copyright (c) 2002 Paul Mundt <lethal@chaoticdreams.org>
+ *
+ * Released under the terms of the GNU GPL v2.0.
+ *
+ */
+
+#include <linux/time.h>
+#include <asm/rtc.h>
+#include <asm/io.h>
+
+/* The AICA RTC has an Epoch of 1/1/1950, so we must subtract 20 years (in
+ seconds) to get the standard Unix Epoch when getting the time, and add
+ 20 years when setting the time. */
+#define TWENTY_YEARS ((20 * 365LU + 5) * 86400)
+
+/* The AICA RTC is represented by a 32-bit seconds counter stored in 2 16-bit
+ registers.*/
+#define AICA_RTC_SECS_H 0xa0710000
+#define AICA_RTC_SECS_L 0xa0710004
+
+/**
+ * aica_rtc_gettimeofday - Get the time from the AICA RTC
+ * @ts: pointer to resulting timespec
+ *
+ * Grabs the current RTC seconds counter and adjusts it to the Unix Epoch.
+ */
+static void aica_rtc_gettimeofday(struct timespec *ts)
+{
+ unsigned long val1, val2;
+
+ do {
+ val1 = ((__raw_readl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+ (__raw_readl(AICA_RTC_SECS_L) & 0xffff);
+
+ val2 = ((__raw_readl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+ (__raw_readl(AICA_RTC_SECS_L) & 0xffff);
+ } while (val1 != val2);
+
+ ts->tv_sec = val1 - TWENTY_YEARS;
+
+ /* Can't get nanoseconds with just a seconds counter. */
+ ts->tv_nsec = 0;
+}
+
+/**
+ * aica_rtc_settimeofday - Set the AICA RTC to the current time
+ * @secs: contains the time_t to set
+ *
+ * Adjusts the given @tv to the AICA Epoch and sets the RTC seconds counter.
+ */
+static int aica_rtc_settimeofday(const time_t secs)
+{
+ unsigned long val1, val2;
+ unsigned long adj = secs + TWENTY_YEARS;
+
+ do {
+ __raw_writel((adj & 0xffff0000) >> 16, AICA_RTC_SECS_H);
+ __raw_writel((adj & 0xffff), AICA_RTC_SECS_L);
+
+ val1 = ((__raw_readl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+ (__raw_readl(AICA_RTC_SECS_L) & 0xffff);
+
+ val2 = ((__raw_readl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+ (__raw_readl(AICA_RTC_SECS_L) & 0xffff);
+ } while (val1 != val2);
+
+ return 0;
+}
+
+void aica_time_init(void)
+{
+ rtc_sh_get_time = aica_rtc_gettimeofday;
+ rtc_sh_set_time = aica_rtc_settimeofday;
+}
+
diff --git a/arch/sh/boards/mach-dreamcast/setup.c b/arch/sh/boards/mach-dreamcast/setup.c
new file mode 100644
index 00000000000..ad1a4db72e0
--- /dev/null
+++ b/arch/sh/boards/mach-dreamcast/setup.c
@@ -0,0 +1,41 @@
+/*
+ * arch/sh/boards/dreamcast/setup.c
+ *
+ * Hardware support for the Sega Dreamcast.
+ *
+ * Copyright (c) 2001, 2002 M. R. Brown <mrbrown@linuxdc.org>
+ * Copyright (c) 2002, 2003, 2004 Paul Mundt <lethal@linux-sh.org>
+ *
+ * This file is part of the LinuxDC project (www.linuxdc.org)
+ *
+ * Released under the terms of the GNU GPL v2.0.
+ *
+ * This file originally bore the message (with enclosed-$):
+ * Id: setup_dc.c,v 1.5 2001/05/24 05:09:16 mrbrown Exp
+ * SEGA Dreamcast support
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/device.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/rtc.h>
+#include <asm/machvec.h>
+#include <mach/sysasic.h>
+
+static void __init dreamcast_setup(char **cmdline_p)
+{
+ board_time_init = aica_time_init;
+}
+
+static struct sh_machine_vector mv_dreamcast __initmv = {
+ .mv_name = "Sega Dreamcast",
+ .mv_setup = dreamcast_setup,
+ .mv_irq_demux = systemasic_irq_demux,
+ .mv_init_irq = systemasic_irq_init,
+};