arch/powerpc/boot/cuboot-acadia.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Old U-boot compatibility for Acadia
   4  *
   5  * Author: Josh Boyer <jwboyer@linux.vnet.ibm.com>
   6  *
   7  * Copyright 2008 IBM Corporation
   8  */
   9
  10 #include "ops.h"
  11 #include "io.h"
  12 #include "dcr.h"
  13 #include "stdio.h"
  14 #include "4xx.h"
  15 #include "44x.h"
  16 #include "cuboot.h"
  17
  18 #define TARGET_4xx
  19 #include "ppcboot.h"
  20
  21 static bd_t bd;
  22
  23 #define CPR_PERD0_SPIDV_MASK   0x000F0000     /* SPI Clock Divider */
  24
  25 #define PLLC_SRC_MASK          0x20000000     /* PLL feedback source */
  26
  27 #define PLLD_FBDV_MASK         0x1F000000     /* PLL feedback divider value */
  28 #define PLLD_FWDVA_MASK        0x000F0000     /* PLL forward divider A value */
  29 #define PLLD_FWDVB_MASK        0x00000700     /* PLL forward divider B value */
  30
  31 #define PRIMAD_CPUDV_MASK      0x0F000000     /* CPU Clock Divisor Mask */
  32 #define PRIMAD_PLBDV_MASK      0x000F0000     /* PLB Clock Divisor Mask */
  33 #define PRIMAD_OPBDV_MASK      0x00000F00     /* OPB Clock Divisor Mask */
  34 #define PRIMAD_EBCDV_MASK      0x0000000F     /* EBC Clock Divisor Mask */
  35
  36 #define PERD0_PWMDV_MASK       0xFF000000     /* PWM Divider Mask */
  37 #define PERD0_SPIDV_MASK       0x000F0000     /* SPI Divider Mask */
  38 #define PERD0_U0DV_MASK        0x0000FF00     /* UART 0 Divider Mask */
  39 #define PERD0_U1DV_MASK        0x000000FF     /* UART 1 Divider Mask */
  40
  41 static void get_clocks(void)
  42 {
  43         unsigned long sysclk, cpr_plld, cpr_pllc, cpr_primad, plloutb, i;
  44         unsigned long pllFwdDiv, pllFwdDivB, pllFbkDiv, pllPlbDiv, pllExtBusDiv;
  45         unsigned long pllOpbDiv, freqEBC, freqUART, freqOPB;
  46         unsigned long div;              /* total divisor udiv * bdiv */
  47         unsigned long umin;             /* minimum udiv */
  48         unsigned short diff;            /* smallest diff */
  49         unsigned long udiv;             /* best udiv */
  50         unsigned short idiff;           /* current diff */
  51         unsigned short ibdiv;           /* current bdiv */
  52         unsigned long est;              /* current estimate */
  53         unsigned long baud;
  54         void *np;
  55
  56         /* read the sysclk value from the CPLD */
  57         sysclk = (in_8((unsigned char *)0x80000000) == 0xc) ? 66666666 : 33333000;
  58
  59         /*
  60          * Read PLL Mode registers
  61          */
  62         cpr_plld = CPR0_READ(DCRN_CPR0_PLLD);
  63         cpr_pllc = CPR0_READ(DCRN_CPR0_PLLC);
  64
  65         /*
  66          * Determine forward divider A
  67          */
  68         pllFwdDiv = ((cpr_plld & PLLD_FWDVA_MASK) >> 16);
  69
  70         /*
  71          * Determine forward divider B
  72          */
  73         pllFwdDivB = ((cpr_plld & PLLD_FWDVB_MASK) >> 8);
  74         if (pllFwdDivB == 0)
  75                 pllFwdDivB = 8;
  76
  77         /*
  78          * Determine FBK_DIV.
  79          */
  80         pllFbkDiv = ((cpr_plld & PLLD_FBDV_MASK) >> 24);
  81         if (pllFbkDiv == 0)
  82                 pllFbkDiv = 256;
  83
  84         /*
  85          * Read CPR_PRIMAD register
  86          */
  87         cpr_primad = CPR0_READ(DCRN_CPR0_PRIMAD);
  88
  89         /*
  90          * Determine PLB_DIV.
  91          */
  92         pllPlbDiv = ((cpr_primad & PRIMAD_PLBDV_MASK) >> 16);
  93         if (pllPlbDiv == 0)
  94                 pllPlbDiv = 16;
  95
  96         /*
  97          * Determine EXTBUS_DIV.
  98          */
  99         pllExtBusDiv = (cpr_primad & PRIMAD_EBCDV_MASK);
 100         if (pllExtBusDiv == 0)
 101                 pllExtBusDiv = 16;
 102
 103         /*
 104          * Determine OPB_DIV.
 105          */
 106         pllOpbDiv = ((cpr_primad & PRIMAD_OPBDV_MASK) >> 8);
 107         if (pllOpbDiv == 0)
 108                 pllOpbDiv = 16;
 109
 110         /* There is a bug in U-Boot that prevents us from using
 111          * bd.bi_opbfreq because U-Boot doesn't populate it for
 112          * 405EZ.  We get to calculate it, yay!
 113          */
 114         freqOPB = (sysclk *pllFbkDiv) /pllOpbDiv;
 115
 116         freqEBC = (sysclk * pllFbkDiv) / pllExtBusDiv;
 117
 118         plloutb = ((sysclk * ((cpr_pllc & PLLC_SRC_MASK) ?
 119                                            pllFwdDivB : pllFwdDiv) *
 120                     pllFbkDiv) / pllFwdDivB);
 121
 122         np = find_node_by_alias("serial0");
 123         if (getprop(np, "current-speed", &baud, sizeof(baud)) != sizeof(baud))
 124                 fatal("no current-speed property\n\r");
 125
 126         udiv = 256;                     /* Assume lowest possible serial clk */
 127         div = plloutb / (16 * baud); /* total divisor */
 128         umin = (plloutb / freqOPB) << 1;        /* 2 x OPB divisor */
 129         diff = 256;                     /* highest possible */
 130
 131         /* i is the test udiv value -- start with the largest
 132          * possible (256) to minimize serial clock and constrain
 133          * search to umin.
 134          */
 135         for (i = 256; i > umin; i--) {
 136                 ibdiv = div / i;
 137                 est = i * ibdiv;
 138                 idiff = (est > div) ? (est-div) : (div-est);
 139                 if (idiff == 0) {
 140                         udiv = i;
 141                         break;      /* can't do better */
 142                 } else if (idiff < diff) {
 143                         udiv = i;       /* best so far */
 144                         diff = idiff;   /* update lowest diff*/
 145                 }
 146         }
 147         freqUART = plloutb / udiv;
 148
 149         dt_fixup_cpu_clocks(bd.bi_procfreq, bd.bi_intfreq, bd.bi_plb_busfreq);
 150         dt_fixup_clock("/plb/ebc", freqEBC);
 151         dt_fixup_clock("/plb/opb", freqOPB);
 152         dt_fixup_clock("/plb/opb/serial@ef600300", freqUART);
 153         dt_fixup_clock("/plb/opb/serial@ef600400", freqUART);
 154 }
 155
 156 static void acadia_fixups(void)
 157 {
 158         dt_fixup_memory(bd.bi_memstart, bd.bi_memsize);
 159         get_clocks();
 160         dt_fixup_mac_address_by_alias("ethernet0", bd.bi_enetaddr);
 161 }
 162
 163 void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
 164                 unsigned long r6, unsigned long r7)
 165 {
 166         CUBOOT_INIT();
 167         platform_ops.fixups = acadia_fixups;
 168         platform_ops.exit = ibm40x_dbcr_reset;
 169         fdt_init(_dtb_start);
 170         serial_console_init();
 171 }