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Diffstat (limited to 'arch/powerpc/boot/mpc8xx.c')
-rw-r--r-- | arch/powerpc/boot/mpc8xx.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/powerpc/boot/mpc8xx.c b/arch/powerpc/boot/mpc8xx.c new file mode 100644 index 000000000..c9bd9285c --- /dev/null +++ b/arch/powerpc/boot/mpc8xx.c @@ -0,0 +1,81 @@ +/* + * MPC8xx support functions + * + * Author: Scott Wood <scottwood@freescale.com> + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + */ + +#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; +} |