104 lines
2.1 KiB
C
104 lines
2.1 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
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*/
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/errno.h>
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#define PIC32_NULL 0x00
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#define PIC32_RD 0x01
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#define PIC32_SYSRD 0x02
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#define PIC32_WR 0x10
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#define PIC32_SYSWR 0x20
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#define PIC32_IRQ_CLR 0x40
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#define PIC32_STATUS 0x80
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#define DELAY() udelay(100) /* FIXME: needed? */
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/* spinlock to ensure atomic access to PIC32 */
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static DEFINE_SPINLOCK(pic32_bus_lock);
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/* FIXME: io_remap these */
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static void __iomem *bus_xfer = (void __iomem *)0xbf000600;
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static void __iomem *bus_status = (void __iomem *)0xbf000060;
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static inline unsigned int ioready(void)
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{
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return readl(bus_status) & 1;
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}
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static inline void wait_ioready(void)
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{
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do { } while (!ioready());
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}
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static inline void wait_ioclear(void)
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{
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do { } while (ioready());
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}
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static inline void check_ioclear(void)
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{
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if (ioready()) {
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pr_debug("ioclear: initially busy\n");
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do {
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(void) readl(bus_xfer);
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DELAY();
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} while (ioready());
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pr_debug("ioclear: cleared busy\n");
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}
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}
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u32 pic32_bus_readl(u32 reg)
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{
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unsigned long flags;
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u32 status, val;
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spin_lock_irqsave(&pic32_bus_lock, flags);
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check_ioclear();
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writel((PIC32_RD << 24) | (reg & 0x00ffffff), bus_xfer);
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DELAY();
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wait_ioready();
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status = readl(bus_xfer);
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DELAY();
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val = readl(bus_xfer);
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wait_ioclear();
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pr_debug("pic32_bus_readl: *%x -> %x (status=%x)\n", reg, val, status);
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spin_unlock_irqrestore(&pic32_bus_lock, flags);
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return val;
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}
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void pic32_bus_writel(u32 val, u32 reg)
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{
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unsigned long flags;
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u32 status;
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spin_lock_irqsave(&pic32_bus_lock, flags);
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check_ioclear();
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writel((PIC32_WR << 24) | (reg & 0x00ffffff), bus_xfer);
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DELAY();
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writel(val, bus_xfer);
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DELAY();
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wait_ioready();
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status = readl(bus_xfer);
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wait_ioclear();
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pr_debug("pic32_bus_writel: *%x <- %x (status=%x)\n", reg, val, status);
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spin_unlock_irqrestore(&pic32_bus_lock, flags);
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}
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