70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/*
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Copyright (C) 2012, Aaron Lindsay <aaron@aclindsay.com>
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This file is part of Aedrix.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <types.h>
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/* Mailbox Memory-Mapped Registers */
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#define VC_MMU_IO_OFFSET(addr) (addr - 0x7E000000 + 0x20000000)
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#define MBOX0_READ VC_MMU_IO_OFFSET(0x7E00B880)
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/* MBOX0_READ layout:
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31-4 data The 28 bits of data sent to the CPU
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3-0 channel The mailbox channel number from which the data originated */
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#define MBOX0_PEEK VC_MMU_IO_OFFSET(0x7E00B890) //Read from the mailbox without removing data from it.
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#define MBOX0_SENDER VC_MMU_IO_OFFSET(0x7E00B894) //Sender ID (bottom 2 bits only)
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#define MBOX0_STATUS VC_MMU_IO_OFFSET(0x7E00B898)
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/* MBOX0_STATUS layout:
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31 full Set if the mailbox is full, and thus no more data can be written to it.
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30 empty Set if the mailbox is empty, and thus no more data is available to be read from it.
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29-0 unused? */
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#define MBOX0_CONFIG VC_MMU_IO_OFFSET(0x7E00B89C)
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#define MBOX0_WRITE VC_MMU_IO_OFFSET(0x7E00B8A0) //also MBOX1_READ?
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/* MBOX0_WRITE layout:
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31-4 data The 28 bits of data to be sent
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3-0 channel The mailbox channel to send data to */
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#define MBOX0_STATUS_FULL 0x80000000
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#define MBOX0_STATUS_EMPTY 0x40000000
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uint32 mailbox_read(uint32 channel) {
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uint32 mbox_msg;
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while (1) {
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int i;
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for (i = 0; *(volatile uint32 *)MBOX0_STATUS & MBOX0_STATUS_EMPTY; i++) {
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if (i >= 1<<20)
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return 0xFFFFFFFF;
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}
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mbox_msg = *(volatile uint32 *)MBOX0_READ;
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if ((mbox_msg & 0xf) == channel)
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return mbox_msg & ~0xf;
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}
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}
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void mailbox_write(uint32 channel, uint32 data) {
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channel &= 0xf;
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data &= ~0xf;
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while (*(volatile uint32 *)MBOX0_STATUS & MBOX0_STATUS_FULL);
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*(volatile uint32 *)MBOX0_WRITE = channel | data;
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}
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