kernel: dev: Add HPET driver

Signed-off-by: sigsegv7 <ian@vegaa.systems>

4 files changed, 229 insertions, 2 deletions

diff --git a/sys/dev/timer/hpet.c b/sys/dev/timer/hpet.c
new file mode 100644
index 0000000..1089096
--- /dev/null
+++ b/sys/dev/timer/hpet.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of VegaOS nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <dev/timer/hpet.h>
+#include <firmware/acpi/acpi.h>
+#include <sys/panic.h>
+#include <sys/cdefs.h>
+#include <sys/syslog.h>
+#include <sys/mmio.h>
+
+__MODULE_NAME("hpet");
+__KERNEL_META("$Vega$: hpet.c, Ian Marco Moffett, "
+              "HPET driver");
+
+#define HPET_REG_CAPS               0x00
+#define HPET_GENERAL_CONFIG         0x10
+#define HPET_REG_MAIN_COUNTER       0xF0
+
+#define CAP_REV_ID(caps)            __SHIFTOUT(caps, 0xFF)
+#define CAP_NUM_TIM(caps)           __SHIFTOUT(caps, 0x1F << 8)
+#define CAP_COUNT_SIZE(caps)        __SHIFTOUT(caps, __BIT(13))
+#define CAP_VENDOR_ID(caps)         __SHIFTOUT(caps, 0xFFFF << 16)
+#define CAP_CLK_PERIOD(caps)        (caps >> 32)
+
+/*
+ * TODO: Use some sort of helper function that
+ *       uses PAUSE or some similar instruction
+ *       for the current architecture. It is
+ *       *not* a good idea to spin for a prolonged
+ *       amount of time without it. For now we'll
+ *       just use PAUSE on x86_64 like this.
+ */
+#if defined(__x86_64__)
+#define spinwait_hint()   __ASMV("pause")
+#else
+#define spinwait_hint()   __nothing
+#endif  /* defined(__x86_64__) */
+
+static struct hpet *acpi_hpet = NULL;
+static void *hpet_base = NULL;
+static bool is_faulty = false;
+
+/*
+ * Read from HPET register space.
+ *
+ * @reg: Register to read from.
+ */
+static inline uint64_t
+hpet_read(uint32_t reg)
+{
+    void *addr;
+
+    addr = (void *)((uintptr_t)hpet_base + reg);
+    return mmio_read64(addr);
+}
+
+/*
+ * Write to HPET register space.
+ *
+ * @reg: Register to write to.
+ * @val: Value to write.
+ */
+static inline void
+hpet_write(uint32_t reg, uint64_t val)
+{
+    void *addr;
+
+    addr = (void *)((uintptr_t)hpet_base + reg);
+    mmio_write64(addr, val);
+}
+
+void
+hpet_msleep(size_t ms)
+{
+    uint64_t caps;
+    uint32_t period;
+    uint64_t counter_val;
+    volatile size_t ticks;
+
+    caps = hpet_read(HPET_REG_CAPS);
+    period = CAP_CLK_PERIOD(caps);
+    counter_val = hpet_read(HPET_REG_MAIN_COUNTER);
+
+    ticks = counter_val + (ms * (1000000000000 / period));
+
+    while (hpet_read(HPET_REG_MAIN_COUNTER) < ticks) {
+        spinwait_hint();
+    }
+}
+
+int
+hpet_init(void)
+{
+    struct acpi_gas *gas;
+    uint64_t caps;
+
+    acpi_hpet = acpi_query("HPET");
+    if (acpi_hpet == NULL)
+        return 1;       /* Not found */
+
+    gas = &acpi_hpet->gas;
+    hpet_base = (void *)gas->address;
+    caps = hpet_read(HPET_REG_CAPS);
+
+    /* Ensure caps aren't bogus */
+    if (CAP_REV_ID(caps) == 0) {
+        KERR("Found bogus revision, assuming faulty\n");
+        is_faulty = true;
+        return 1;
+    }
+    if (CAP_CLK_PERIOD(caps) > 0x05F5E100) {
+        /*
+         * The spec states this counter clk period
+         * must be <= 0x05F5E100. So we'll consider it
+         * as bogus if it exceeds this value
+         */
+        KERR("Found bogus COUNTER_CLK_PERIOD, assuming faulty\n");
+        KINFO("HPET REV - 0x%x\n", CAP_REV_ID(caps));
+        KINFO("COUNTER_CLK_PERIOD - 0x%x\n", CAP_CLK_PERIOD(caps));
+        is_faulty = true;
+        return 1;
+    }
+
+    KINFO("HPET integrity verified\n");
+
+    hpet_write(HPET_REG_MAIN_COUNTER, 0);
+    hpet_write(HPET_GENERAL_CONFIG, 1);
+
+    /* Not faulty */
+    is_faulty = false;
+    return 0;
+}
diff --git a/sys/firmware/acpi/acpi_init.c b/sys/firmware/acpi/acpi_init.c
index 67c4d9c..89ce786 100644
--- a/sys/firmware/acpi/acpi_init.c
+++ b/sys/firmware/acpi/acpi_init.c
@@ -33,6 +33,7 @@
 #include <sys/cdefs.h>
 #include <sys/panic.h>
 #include <sys/syslog.h>
+#include <dev/timer/hpet.h>
 #include <vm/vm.h>
 
 __MODULE_NAME("acpi");
@@ -107,4 +108,12 @@ acpi_init(void)
     }
     root_sdt_entries = (root_sdt->hdr.length - sizeof(root_sdt->hdr)) / 4;
     acpi_parse_madt();
+
+#if defined(__x86_64__)
+    /* Vega requires HPET on x86_64 */
+    if (hpet_init() != 0)
+        panic("Machine does not support HPET!\n");
+#else
+    hpet_init();
+#endif  /* defined(__x86_64__) */
 }
diff --git a/sys/include/dev/timer/hpet.h b/sys/include/dev/timer/hpet.h
new file mode 100644
index 0000000..513444e
--- /dev/null
+++ b/sys/include/dev/timer/hpet.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of VegaOS nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _TIMER_HPET_H_
+#define _TIMER_HPET_H_
+
+#include <sys/types.h>
+
+int hpet_init(void);
+void hpet_msleep(size_t ms);
+
+#endif  /* !_TIMER_HPET_H_ */
diff --git a/sys/include/firmware/acpi/tables.h b/sys/include/firmware/acpi/tables.h
index c145e90..2d65f46 100644
--- a/sys/include/firmware/acpi/tables.h
+++ b/sys/include/firmware/acpi/tables.h
@@ -51,7 +51,7 @@ struct __packed acpi_rsdp {
     uint64_t signature;         /* RSD PTR */
     uint8_t checksum;           /* Structure checksum */
     char oemid[OEMID_SIZE];     /* OEM-supplied string that IDs the OEM */
-    uint8_t revision;           /* Revision of the structure */ 
+    uint8_t revision;           /* Revision of the structure */
     uint32_t rsdt_addr;         /* RSDT physical address */
 
     /* Reserved if revision < 2 */
@@ -61,7 +61,7 @@ struct __packed acpi_rsdp {
     uint8_t reserved[3];
 };
 
-/* 
+/*
  * XSDT or RSDT depending
  * on what revision the header
  * says.
@@ -105,4 +105,26 @@ struct __packed interrupt_override {
     uint16_t flags;
 };
 
+struct __packed acpi_gas {
+    uint8_t address_space_id;
+    uint8_t register_bit_width;
+    uint8_t register_bit_offset;
+    uint8_t reserved;
+    uint64_t address;
+};
+
+struct __packed hpet {
+    struct acpi_header hdr;
+    uint8_t hardware_rev_id;
+    uint8_t comparator_count : 5;
+    uint8_t counter_size : 1;
+    uint8_t reserved : 1;
+    uint8_t legacy_replacement : 1;
+    uint16_t pci_vendor_id;
+    struct acpi_gas gas;
+    uint8_t hpet_number;
+    uint16_t minimum_tick;
+    uint8_t page_protection;
+};
+
 #endif      /* !_ACPI_TABLES_H_ */