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-rw-r--r--arch/powerpc/boot/mpc8xx.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/arch/powerpc/boot/mpc8xx.c b/arch/powerpc/boot/mpc8xx.c
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+++ b/arch/powerpc/boot/mpc8xx.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MPC8xx support functions
+ *
+ * Author: Scott Wood <scottwood@freescale.com>
+ *
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ */
+
+#include "ops.h"
+#include "types.h"
+#include "fsl-soc.h"
+#include "mpc8xx.h"
+#include "stdio.h"
+#include "io.h"
+
+#define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */
+
+/* Return system clock from crystal frequency */
+u32 mpc885_get_clock(u32 crystal)
+{
+ u32 *immr;
+ u32 plprcr;
+ int mfi, mfn, mfd, pdf;
+ u32 ret;
+
+ immr = fsl_get_immr();
+ if (!immr) {
+ printf("mpc885_get_clock: Couldn't get IMMR base.\r\n");
+ return 0;
+ }
+
+ plprcr = in_be32(&immr[MPC8XX_PLPRCR]);
+
+ mfi = (plprcr >> 16) & 15;
+ if (mfi < 5) {
+ printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r\n",
+ mfi);
+ mfi = 5;
+ }
+
+ pdf = (plprcr >> 1) & 0xf;
+ mfd = (plprcr >> 22) & 0x1f;
+ mfn = (plprcr >> 27) & 0x1f;
+
+ ret = crystal * mfi;
+
+ if (mfn != 0)
+ ret += crystal * mfn / (mfd + 1);
+
+ return ret / (pdf + 1);
+}
+
+/* Set common device tree fields based on the given clock frequencies. */
+void mpc8xx_set_clocks(u32 sysclk)
+{
+ void *node;
+
+ dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk);
+
+ node = finddevice("/soc/cpm");
+ if (node)
+ setprop(node, "clock-frequency", &sysclk, 4);
+
+ node = finddevice("/soc/cpm/brg");
+ if (node)
+ setprop(node, "clock-frequency", &sysclk, 4);
+}
+
+int mpc885_fixup_clocks(u32 crystal)
+{
+ u32 sysclk = mpc885_get_clock(crystal);
+ if (!sysclk)
+ return 0;
+
+ mpc8xx_set_clocks(sysclk);
+ return 1;
+}