Initial revision

cpu/mpc824x/speed.c

+/*
+ * (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);
+}