/* * (C) Copyright 2001 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. * * 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 */ /* * This provides a bit-banged interface to the ethernet MII management * channel. */ #include <common.h> #include <ioports.h> #include <ppc_asm.tmpl> #ifdef CONFIG_BITBANGMII /***************************************************************************** * * Utility to send the preamble, address, and register (common to read * and write). */ static void miiphy_pre(char read, unsigned char addr, unsigned char reg) { int j; /* counter */ volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, MDIO_PORT); /* * Send a 32 bit preamble ('1's) with an extra '1' bit for good measure. * The IEEE spec says this is a PHY optional requirement. The AMD * 79C874 requires one after power up and one after a MII communications * error. This means that we are doing more preambles than we need, * but it is safer and will be much more robust. */ MDIO_ACTIVE; MDIO(1); for(j = 0; j < 32; j++) { MDC(0); MIIDELAY; MDC(1); MIIDELAY; } /* send the start bit (01) and the read opcode (10) or write (10) */ MDC(0); MDIO(0); MIIDELAY; MDC(1); MIIDELAY; MDC(0); MDIO(1); MIIDELAY; MDC(1); MIIDELAY; MDC(0); MDIO(read); MIIDELAY; MDC(1); MIIDELAY; MDC(0); MDIO(!read); MIIDELAY; MDC(1); MIIDELAY; /* send the PHY address */ for(j = 0; j < 5; j++) { MDC(0); if((addr & 0x10) == 0) { MDIO(0); } else { MDIO(1); } MIIDELAY; MDC(1); MIIDELAY; addr <<= 1; } /* send the register address */ for(j = 0; j < 5; j++) { MDC(0); if((reg & 0x10) == 0) { MDIO(0); } else { MDIO(1); } MIIDELAY; MDC(1); MIIDELAY; reg <<= 1; } } /***************************************************************************** * * Read a MII PHY register. * * Returns: * 0 on success */ int miiphy_read(unsigned char addr, unsigned char reg, unsigned short *value) { short rdreg; /* register working value */ int j; /* counter */ volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, MDIO_PORT); miiphy_pre(1, addr, reg); /* tri-state our MDIO I/O pin so we can read */ MDC(0); MDIO_TRISTATE; MIIDELAY; MDC(1); MIIDELAY; /* check the turnaround bit: the PHY should be driving it to zero */ if(MDIO_READ != 0) { /* printf("PHY didn't drive TA low\n"); */ for(j = 0; j < 32; j++) { MDC(0); MIIDELAY; MDC(1); MIIDELAY; } return(-1); } MDC(0); MIIDELAY; /* read 16 bits of register data, MSB first */ rdreg = 0; for(j = 0; j < 16; j++) { MDC(1); MIIDELAY; rdreg <<= 1; rdreg |= MDIO_READ; MDC(0); MIIDELAY; } MDC(1); MIIDELAY; MDC(0); MIIDELAY; MDC(1); MIIDELAY; *value = rdreg; #ifdef DEBUG printf ("miiphy_read(0x%x) @ 0x%x = 0x%04x\n", reg, addr, *value); #endif return 0; } /***************************************************************************** * * Write a MII PHY register. * * Returns: * 0 on success */ int miiphy_write(unsigned char addr, unsigned char reg, unsigned short value) { int j; /* counter */ volatile ioport_t *iop = ioport_addr((immap_t *)CFG_IMMR, MDIO_PORT); miiphy_pre(0, addr, reg); /* send the turnaround (10) */ MDC(0); MDIO(1); MIIDELAY; MDC(1); MIIDELAY; MDC(0); MDIO(0); MIIDELAY; MDC(1); MIIDELAY; /* write 16 bits of register data, MSB first */ for(j = 0; j < 16; j++) { MDC(0); if((value & 0x00008000) == 0) { MDIO(0); } else { MDIO(1); } MIIDELAY; MDC(1); MIIDELAY; value <<= 1; } /* * Tri-state the MDIO line. */ MDIO_TRISTATE; MDC(0); MIIDELAY; MDC(1); MIIDELAY; return 0; } #endif /* CONFIG_BITBANGMII */