• Luis R. Rodriguez's avatar
    video: fbdev: neofb: use arch_phys_wc_add() and ioremap_wc() · f2081b81
    Luis R. Rodriguez authored
    Convert the driver from using the x86 specific MTRR code to
    the architecture agnostic arch_phys_wc_add(). arch_phys_wc_add()
    will avoid MTRR if write-combining is available, in order to
    take advantage of that also ensure the ioremap'd area is requested
    as write-combining.
    
    There are a few motivations for this:
    
    a) Take advantage of PAT when available
    
    b) Help bury MTRR code away, MTRR is architecture specific and on
       x86 its replaced by PAT
    
    c) Help with the goal of eventually using _PAGE_CACHE_UC over
       _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
       de33c442 titled "x86 PAT: fix performance drop for glx,
       use UC minus for ioremap(), ioremap_nocache() and
       pci_mmap_page_range()")
    
    The conversion done is expressed by the following Coccinelle
    SmPL patch, it additionally required manual intervention to
    address all the #ifdery and removal of redundant things which
    arch_phys_wc_add() already addresses such as verbose message
    about when MTRR fails and doing nothing when we didn't get
    an MTRR.
    
    @ mtrr_found @
    expression index, base, size;
    @@
    
    -index = mtrr_add(base, size, MTRR_TYPE_WRCOMB, 1);
    +index = arch_phys_wc_add(base, size);
    
    @ mtrr_rm depends on mtrr_found @
    expression mtrr_found.index, mtrr_found.base, mtrr_found.size;
    @@
    
    -mtrr_del(index, base, size);
    +arch_phys_wc_del(index);
    
    @ mtrr_rm_zero_arg depends on mtrr_found @
    expression mtrr_found.index;
    @@
    
    -mtrr_del(index, 0, 0);
    +arch_phys_wc_del(index);
    
    @ mtrr_rm_fb_info depends on mtrr_found @
    struct fb_info *info;
    expression mtrr_found.index;
    @@
    
    -mtrr_del(index, info->fix.smem_start, info->fix.smem_len);
    +arch_phys_wc_del(index);
    
    @ ioremap_replace_nocache depends on mtrr_found @
    struct fb_info *info;
    expression base, size;
    @@
    
    -info->screen_base = ioremap_nocache(base, size);
    +info->screen_base = ioremap_wc(base, size);
    
    @ ioremap_replace_default depends on mtrr_found @
    struct fb_info *info;
    expression base, size;
    @@
    
    -info->screen_base = ioremap(base, size);
    +info->screen_base = ioremap_wc(base, size);
    
    Generated-by: Coccinelle SmPL
    Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
    Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
    Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
    Cc: Jingoo Han <jg1.han@samsung.com>
    Cc: Suresh Siddha <sbsiddha@gmail.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Dave Airlie <airlied@redhat.com>
    Cc: Antonino Daplas <adaplas@gmail.com>
    Cc: linux-fbdev@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: 's avatarLuis R. Rodriguez <mcgrof@suse.com>
    Reviewed-by: 's avatarDave Airlie <airlied@redhat.com>
    Signed-off-by: 's avatarTomi Valkeinen <tomi.valkeinen@ti.com>
    f2081b81
neomagic.h 4.9 KB