From cf7c06297d04bade9cd04c056f9ed510e64dd7bd Mon Sep 17 00:00:00 2001
From: Uros Majstorovic <majstor@majstor.org>
Date: Wed, 5 Aug 2020 03:39:22 +0200
Subject: code -> fw

---
 fw/fe310/bsp/drivers/prci_driver.h | 80 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 fw/fe310/bsp/drivers/prci_driver.h

(limited to 'fw/fe310/bsp/drivers/prci_driver.h')

diff --git a/fw/fe310/bsp/drivers/prci_driver.h b/fw/fe310/bsp/drivers/prci_driver.h
new file mode 100644
index 0000000..14e1370
--- /dev/null
+++ b/fw/fe310/bsp/drivers/prci_driver.h
@@ -0,0 +1,80 @@
+// See LICENSE file for license details
+
+#ifndef _PRCI_DRIVER_H_
+#define _PRCI_DRIVER_H_
+
+__BEGIN_DECLS
+
+#include <unistd.h>
+
+typedef enum prci_freq_target {
+
+  PRCI_FREQ_OVERSHOOT,
+  PRCI_FREQ_CLOSEST,
+  PRCI_FREQ_UNDERSHOOT
+
+} PRCI_freq_target;
+
+/* Measure and return the approximate frequency of the
+ * CPU, as given by measuring the mcycle counter against
+ * the mtime ticks.
+ */
+uint32_t PRCI_measure_mcycle_freq(uint32_t mtime_ticks, uint32_t mtime_freq);
+unsigned long PRCI_get_cpu_freq();
+
+/* Safely switch over to the HFROSC using the given div
+ * and trim settings.
+ */
+void PRCI_use_hfrosc(int div, int trim);
+
+/* Safely switch over to the 16MHz HFXOSC,
+ * applying the finaldiv clock divider (1 is the lowest
+ * legal value).
+ */
+void PRCI_use_hfxosc(uint32_t finaldiv);
+
+/* Safely switch over to the PLL using the given
+ * settings.
+ *
+ * Note that not all combinations of the inputs are actually
+ * legal, and this function does not check for their
+ * legality ("safely" means that this function won't turn off
+ * or glitch the clock the CPU is actually running off, but
+ * doesn't protect against you making it too fast or slow.)
+ */
+
+void PRCI_use_pll(int refsel, int bypass,
+			 int r, int f, int q, int finaldiv,
+			 int hfroscdiv, int hfrosctrim);
+
+/* Use the default clocks configured at reset.
+ * This is ~16Mhz HFROSC and turns off the LFROSC
+ * (on the current FE310 Dev Platforms, an external LFROSC is
+ * used as it is more power efficient).
+ */
+void PRCI_use_default_clocks();
+
+/* This routine will adjust the HFROSC trim
+ * while using HFROSC as the clock source,
+ * measure the resulting frequency, then
+ * use it as the PLL clock source,
+ * in an attempt to get over, under, or close to the
+ * requested frequency. It returns the actual measured
+ * frequency.
+ *
+ * Note that the requested frequency must be within the
+ * range supported by the PLL so not all values are
+ * achievable with this function, and not all
+ * are guaranteed to actually work. The PLL
+ * is rated higher than the hardware.
+ *
+ * There is no check on the desired f_cpu frequency, it
+ * is up to the user to specify something reasonable.
+ */
+
+uint32_t PRCI_set_hfrosctrim_for_f_cpu(uint32_t f_cpu, PRCI_freq_target target);
+
+__END_DECLS
+
+#endif
+
-- 
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