hw/misc: Add NPCM7xx Clock Controller device model

Enough functionality to boot the Linux kernel has been implemented. This
includes:

  - Correct power-on reset values so the various clock rates can be
    accurately calculated.
  - Clock enables stick around when written.

In addition, a best effort attempt to implement SECCNT and CNTR25M was
made even though I don't think the kernel needs them.

Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Message-id: 20200911052101.2602693-3-hskinnemoen@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/include/hw/misc/npcm7xx_clk.h b/include/hw/misc/npcm7xx_clk.h
new file mode 100644
index 0000000000..cdcc9e8534
--- /dev/null
+++ b/include/hw/misc/npcm7xx_clk.h
@@ -0,0 +1,48 @@
+/*
+ * Nuvoton NPCM7xx Clock Control Registers.
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#ifndef NPCM7XX_CLK_H
+#define NPCM7XX_CLK_H
+
+#include "exec/memory.h"
+#include "hw/sysbus.h"
+
+/*
+ * The reference clock frequency for the timer modules, and the SECCNT and
+ * CNTR25M registers in this module, is always 25 MHz.
+ */
+#define NPCM7XX_TIMER_REF_HZ            (25000000)
+
+/*
+ * Number of registers in our device state structure. Don't change this without
+ * incrementing the version_id in the vmstate.
+ */
+#define NPCM7XX_CLK_NR_REGS             (0x70 / sizeof(uint32_t))
+
+typedef struct NPCM7xxCLKState {
+    SysBusDevice parent;
+
+    MemoryRegion iomem;
+
+    uint32_t regs[NPCM7XX_CLK_NR_REGS];
+
+    /* Time reference for SECCNT and CNTR25M, initialized by power on reset */
+    int64_t ref_ns;
+} NPCM7xxCLKState;
+
+#define TYPE_NPCM7XX_CLK "npcm7xx-clk"
+#define NPCM7XX_CLK(obj) OBJECT_CHECK(NPCM7xxCLKState, (obj), TYPE_NPCM7XX_CLK)
+
+#endif /* NPCM7XX_CLK_H */