diff options
Diffstat (limited to 'cpu')
| -rw-r--r-- | cpu/mpc824x/speed.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/cpu/mpc824x/speed.c b/cpu/mpc824x/speed.c new file mode 100644 index 0000000..bd3156d --- /dev/null +++ b/cpu/mpc824x/speed.c @@ -0,0 +1,118 @@ +/* + * (C) Copyright 2001 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * (C) Copyright 2002 + * Gregory E. Allen, gallen@arlut.utexas.edu + * Applied Research Laboratories, The University of Texas at Austin + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <mpc824x.h> +#include <asm/processor.h> + +/* ------------------------------------------------------------------------- */ +/* NOTE: This describes the proper use of this file. + * + * CONFIG_SYS_CLK_FREQ should be defined as the input frequency on + * PCI_SYNC_IN . + * + * CONFIG_PLL_PCI_TO_MEM_MULTIPLIER is only required on MPC8240 + * boards. It should be defined as the PCI to Memory Multiplier as + * documented in the MPC8240 Hardware Specs. + * + * Other mpc824x boards don't need CONFIG_PLL_PCI_TO_MEM_MULTIPLIER + * because they can determine it from the PCR. + * + * Gary Milliorn <gary.milliorn@motorola.com> (who should know since + * he designed the Sandpoint) told us that the PCR is not in all revs + * of the MPC8240 CPU, so it's not guaranteeable and we cannot do + * away with CONFIG_PLL_PCI_TO_MEM_MULTIPLIER altogether. + */ +/* ------------------------------------------------------------------------- */ + +/* This gives the PCI to Memory multiplier times 10 */ +/* The index is the value of PLL_CFG[0:4] */ +/* This is documented in the MPC8240/5 Hardware Specs */ + +short pll_pci_to_mem_multiplier[] = { +#if defined(CONFIG_MPC8240) + 30, 30, 10, 10, 20, 10, 0, 10, + 10, 0, 20, 0, 20, 0, 20, 0, + 30, 0, 15, 0, 20, 0, 20, 0, + 25, 0, 10, 0, 15, 15, 0, 0, +#elif defined(CONFIG_MPC8245) + 30, 30, 10, 10, 20, 10, 10, 10, + 10, 20, 20, 15, 20, 15, 20, 0, + 30, 0, 15, 40, 20, 25, 20, 40, + 25, 20, 10, 20, 15, 15, 15, 0, +#else +#error Specific type of MPC824x must be defined (i.e. CONFIG_MPC8240) +#endif +}; + +#define CU824_PLL_STATE_REG 0xFE80002F +#define PCR 0x800000E2 + +/* ------------------------------------------------------------------------- */ + +/* compute the memory bus clock frequency */ +ulong get_bus_freq (ulong dummy) +{ + unsigned char pll_cfg; +#if defined(CONFIG_MPC8240) && !defined(CONFIG_CU824) + return (CONFIG_SYS_CLK_FREQ) * (CONFIG_PLL_PCI_TO_MEM_MULTIPLIER); +#elif defined(CONFIG_CU824) + pll_cfg = *(volatile unsigned char *) (CU824_PLL_STATE_REG); + pll_cfg &= 0x1f; +#else + CONFIG_READ_BYTE(PCR, pll_cfg); + pll_cfg = (pll_cfg >> 3) & 0x1f; +#endif + return ((CONFIG_SYS_CLK_FREQ) * pll_pci_to_mem_multiplier[pll_cfg] + 5) / 10; +} + + +/* ------------------------------------------------------------------------- */ + +/* This gives the Memory to CPU Core multiplier times 10 */ +/* The index is the value of PLLRATIO in HID1 */ +/* This is documented in the MPC8240 Hardware Specs */ +/* This is not documented for MPC8245 ? FIXME */ +short pllratio_to_factor[] = { + 0, 0, 0, 10, 20, 20, 25, 45, + 30, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 10, 0, 0, 0, 45, + 30, 0, 40, 0, 0, 0, 35, 0, +}; + +/* compute the CPU and memory bus clock frequencies */ +int get_clocks (void) +{ + DECLARE_GLOBAL_DATA_PTR; + + uint hid1 = mfspr(HID1); + hid1 = (hid1 >> (32-5)) & 0x1f; + gd->cpu_clk = (pllratio_to_factor[hid1] * get_bus_freq(0) + 5) + / 10; + gd->bus_clk = get_bus_freq(0); + return (0); +} |