[U-Boot] [PATCH v3 13/18] lcd: Add support for flushing LCD fb from dcache after update

[Mike Frysinger]

On Thursday 12 July 2012 11:25:13 Simon Glass wrote:
> +void lcd_sync(void)
> +{
> +	/*
> +	 * flush_dcache_range() is declared in common.h but it seems that some
> +	 * architectures do not actually implement it. Is there a way to find
> +	 * out whether it exists? For now, ARM is safe.
> +	 */
> +#ifdef CONFIG_ARM
> +	int line_length;
> +
> +	if (lcd_flush_dcache)
> +		flush_dcache_range((u32)lcd_base,
> +			(u32)(lcd_base + lcd_get_size(&line_length)));
> +#endif
> +}

hmm, i think this should be more fine grained

>  	/* Clear the last one */
>  	memset (CONSOLE_ROW_LAST, COLOR_MASK(lcd_color_bg), CONSOLE_ROW_SIZE);
> +	lcd_sync();
>  }

this requires only updating one row and not the entire display right ?  so we 
should only flush that one line.  seems like other parts suffer similar over-
flushing behavior.

> +/**
> + * Set whether we need to flush the dcache when changing the LCD image.
> + * This defaults to off.

i wonder if this default is correct.  perhaps it should default to 1 since 
setting up custom memory maps to disable cache is fairly specially.
-mike
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