On 04/06/15 19:44, Luis R. Rodriguez wrote: > From: "Luis R. Rodriguez" <[email protected]> > > This driver uses the same area for MTRR as for the ioremap_wc(), if > anything it just uses a smaller size in case MTRR reservation fails. > ioremap_wc() API is already used to take advantage of architecture > write-combining when available. > > 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. > > 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 > de33c442e 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: Toshi Kani <[email protected]> > Cc: Suresh Siddha <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: Juergen Gross <[email protected]> > Cc: Daniel Vetter <[email protected]> > Cc: Andy Lutomirski <[email protected]> > Cc: Dave Airlie <[email protected]> > Cc: Antonino Daplas <[email protected]> > Cc: Jean-Christophe Plagniol-Villard <[email protected]> > Cc: Rob Clark <[email protected]> > Cc: Jingoo Han <[email protected]> > Cc: Wolfram Sang <[email protected]> > Cc: Tomi Valkeinen <[email protected]> > Cc: [email protected] > Cc: [email protected] > Signed-off-by: Luis R. Rodriguez <[email protected]> > --- > drivers/video/fbdev/vesafb.c | 29 ++++++++--------------------- > 1 file changed, 8 insertions(+), 21 deletions(-) > > diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c > index 3db3908..528fe91 100644 > --- a/drivers/video/fbdev/vesafb.c > +++ b/drivers/video/fbdev/vesafb.c > @@ -19,10 +19,9 @@ > #include <linux/init.h> > #include <linux/platform_device.h> > #include <linux/screen_info.h> > +#include <linux/io.h> > > #include <video/vga.h> > -#include <asm/io.h> > -#include <asm/mtrr.h> > > #define dac_reg (0x3c8) > #define dac_val (0x3c9) > @@ -180,16 +179,10 @@ static int vesafb_setcolreg(unsigned regno, unsigned > red, unsigned green, > > static void vesafb_destroy(struct fb_info *info) > { > -#ifdef CONFIG_MTRR > struct vesafb_par *par = info->par; > -#endif > > fb_dealloc_cmap(&info->cmap); > - > -#ifdef CONFIG_MTRR > - if (par->wc_cookie >= 0) > - mtrr_del(par->wc_cookie, 0, 0); > -#endif > + arch_phys_wc_del(par->wc_cookie); > if (info->screen_base) > iounmap(info->screen_base); > release_mem_region(info->apertures->ranges[0].base, > info->apertures->ranges[0].size); > @@ -420,7 +413,6 @@ static int vesafb_probe(struct platform_device *dev) > request_region(0x3c0, 32, "vesafb"); > > if (mtrr == 3) { > -#ifdef CONFIG_MTRR > unsigned int temp_size = size_total; > > /* Find the largest power-of-two */ > @@ -428,18 +420,16 @@ static int vesafb_probe(struct platform_device *dev) > > /* Try and find a power of two to add */ > do { > - par->wc_cookie = mtrr_add(vesafb_fix.smem_start, > - temp_size, > - MTRR_TYPE_WRCOMB, 1); > + par->wc_cookie = > + arch_phys_wc_add(vesafb_fix.smem_start, > + temp_size); > temp_size >>= 1; > - } while (temp_size >= PAGE_SIZE && par->wc_cookie == -EINVAL); > -#endif > + } while (temp_size >= PAGE_SIZE && par->wc_cookie < 0); > +
Looks like arch_phys_wc_add prints a warning if it fails, and the above loop may retry it many (?) times. Probably not a big issue, but may be somewhat confusing. Tomi
signature.asc
Description: OpenPGP digital signature
