vss.c

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/*
 * Au1300 media block power gating (VSS)
 *
 * This is a stop-gap solution until I have the clock framework integration
 * ready. This stuff here really must be handled transparently when clocks
 * for various media blocks are enabled/disabled.
 */

#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/mach-au1x00/au1000.h>

#define VSS_GATE    0x00    /* gate wait timers */
#define VSS_CLKRST  0x04    /* clock/block control */
#define VSS_FTR     0x08    /* footers */

#define VSS_ADDR(blk)   (KSEG1ADDR(AU1300_VSS_PHYS_ADDR) + (blk * 0x0c))

static DEFINE_SPINLOCK(au1300_vss_lock);

/* enable a block as outlined in the databook */
static inline void __enable_block(int block)
{
    void __iomem *base = (void __iomem *)VSS_ADDR(block);

    __raw_writel(3, base + VSS_CLKRST); /* enable clock, assert reset */
    wmb();

    __raw_writel(0x01fffffe, base + VSS_GATE); /* maximum setup time */
    wmb();

    /* enable footers in sequence */
    __raw_writel(0x01, base + VSS_FTR);
    wmb();
    __raw_writel(0x03, base + VSS_FTR);
    wmb();
    __raw_writel(0x07, base + VSS_FTR);
    wmb();
    __raw_writel(0x0f, base + VSS_FTR);
    wmb();

    __raw_writel(0x01ffffff, base + VSS_GATE); /* start FSM too */
    wmb();

    __raw_writel(2, base + VSS_CLKRST); /* deassert reset */
    wmb();

    __raw_writel(0x1f, base + VSS_FTR); /* enable isolation cells */
    wmb();
}

/* disable a block as outlined in the databook */
static inline void __disable_block(int block)
{
    void __iomem *base = (void __iomem *)VSS_ADDR(block);

    __raw_writel(0x0f, base + VSS_FTR); /* disable isolation cells */
    wmb();
    __raw_writel(0, base + VSS_GATE);   /* disable FSM */
    wmb();
    __raw_writel(3, base + VSS_CLKRST); /* assert reset */
    wmb();
    __raw_writel(1, base + VSS_CLKRST); /* disable clock */
    wmb();
    __raw_writel(0, base + VSS_FTR);    /* disable all footers */
    wmb();
}

void au1300_vss_block_control(int block, int enable)
{
    unsigned long flags;

    if (alchemy_get_cputype() != ALCHEMY_CPU_AU1300)
        return;

    /* only one block at a time */
    spin_lock_irqsave(&au1300_vss_lock, flags);
    if (enable)
        __enable_block(block);
    else
        __disable_block(block);
    spin_unlock_irqrestore(&au1300_vss_lock, flags);
}
EXPORT_SYMBOL_GPL(au1300_vss_block_control);