[PATCH] staging: omapdrm: Remove unnecessary memcpy

[Rob Clark]

On Thu, Aug 9, 2012 at 12:13 AM, Andy Gross <andy.gross at ti.com> wrote:
> Removed the unnecessary copy of the memory page addresses when
> programming the DMM/PAT and all support code for the lut copy.
> The original intent was to have this code in place for
> suspend/resume functionality w.r.t. DEVICE_OFF.
>
> Performance analysis showed that the extra copy from uncached memory
> led to a fairly hefty penalty when programming large 1D or 2D
> buffers.  This can be implemented in a more efficient manner when we
> actually have to support DEVICE_OFF suspend/resume operations.

This patch itself is ok, but I'd like to wait a bit and merge this
together w/ a 2nd patch that handles saving the PAT state in the
suspend path.

BR,
-R

> Signed-off-by: Andy Gross <andy.gross at ti.com>
> ---
>  drivers/staging/omapdrm/omap_dmm_priv.h  |    6 ------
>  drivers/staging/omapdrm/omap_dmm_tiler.c |   25 +------------------------
>  2 files changed, 1 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/staging/omapdrm/omap_dmm_priv.h b/drivers/staging/omapdrm/omap_dmm_priv.h
> index 08b22e9..09ebc50 100644
> --- a/drivers/staging/omapdrm/omap_dmm_priv.h
> +++ b/drivers/staging/omapdrm/omap_dmm_priv.h
> @@ -141,9 +141,6 @@ struct refill_engine {
>         /* only one trans per engine for now */
>         struct dmm_txn txn;
>
> -       /* offset to lut associated with container */
> -       u32 *lut_offset;
> -
>         wait_queue_head_t wait_for_refill;
>
>         struct list_head idle_node;
> @@ -176,9 +173,6 @@ struct dmm {
>         /* array of LUT - TCM containers */
>         struct tcm **tcm;
>
> -       /* LUT table storage */
> -       u32 *lut;
> -
>         /* allocation list and lock */
>         struct list_head alloc_head;
>  };
> diff --git a/drivers/staging/omapdrm/omap_dmm_tiler.c b/drivers/staging/omapdrm/omap_dmm_tiler.c
> index ec7a5c8..80d3f8a 100644
> --- a/drivers/staging/omapdrm/omap_dmm_tiler.c
> +++ b/drivers/staging/omapdrm/omap_dmm_tiler.c
> @@ -24,7 +24,6 @@
>  #include <linux/interrupt.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/slab.h>
> -#include <linux/vmalloc.h>
>  #include <linux/delay.h>
>  #include <linux/mm.h>
>  #include <linux/time.h>
> @@ -184,9 +183,6 @@ static int dmm_txn_append(struct dmm_txn *txn, struct pat_area *area,
>         int columns = (1 + area->x1 - area->x0);
>         int rows = (1 + area->y1 - area->y0);
>         int i = columns*rows;
> -       u32 *lut = omap_dmm->lut + (engine->tcm->lut_id * omap_dmm->lut_width *
> -                       omap_dmm->lut_height) +
> -                       (area->y0 * omap_dmm->lut_width) + area->x0;
>
>         pat = alloc_dma(txn, sizeof(struct pat), &pat_pa);
>
> @@ -209,10 +205,6 @@ static int dmm_txn_append(struct dmm_txn *txn, struct pat_area *area,
>                         page_to_phys(pages[n]) : engine->dmm->dummy_pa;
>         }
>
> -       /* fill in lut with new addresses */
> -       for (i = 0; i < rows; i++, lut += omap_dmm->lut_width)
> -               memcpy(lut, &data[i*columns], columns * sizeof(u32));
> -
>         txn->last_pat = pat;
>
>         return 0;
> @@ -504,8 +496,6 @@ static int omap_dmm_remove(struct platform_device *dev)
>                 if (omap_dmm->dummy_page)
>                         __free_page(omap_dmm->dummy_page);
>
> -               vfree(omap_dmm->lut);
> -
>                 if (omap_dmm->irq > 0)
>                         free_irq(omap_dmm->irq, omap_dmm);
>
> @@ -521,7 +511,7 @@ static int omap_dmm_probe(struct platform_device *dev)
>  {
>         int ret = -EFAULT, i;
>         struct tcm_area area = {0};
> -       u32 hwinfo, pat_geom, lut_table_size;
> +       u32 hwinfo, pat_geom;
>         struct resource *mem;
>
>         omap_dmm = kzalloc(sizeof(*omap_dmm), GFP_KERNEL);
> @@ -593,16 +583,6 @@ static int omap_dmm_probe(struct platform_device *dev)
>          */
>         writel(0x7e7e7e7e, omap_dmm->base + DMM_PAT_IRQENABLE_SET);
>
> -       lut_table_size = omap_dmm->lut_width * omap_dmm->lut_height *
> -                       omap_dmm->num_lut;
> -
> -       omap_dmm->lut = vmalloc(lut_table_size * sizeof(*omap_dmm->lut));
> -       if (!omap_dmm->lut) {
> -               dev_err(&dev->dev, "could not allocate lut table\n");
> -               ret = -ENOMEM;
> -               goto fail;
> -       }
> -
>         omap_dmm->dummy_page = alloc_page(GFP_KERNEL | __GFP_DMA32);
>         if (!omap_dmm->dummy_page) {
>                 dev_err(&dev->dev, "could not allocate dummy page\n");
> @@ -685,9 +665,6 @@ static int omap_dmm_probe(struct platform_device *dev)
>                 .p1.y = omap_dmm->container_height - 1,
>         };
>
> -       for (i = 0; i < lut_table_size; i++)
> -               omap_dmm->lut[i] = omap_dmm->dummy_pa;
> -
>         /* initialize all LUTs to dummy page entries */
>         for (i = 0; i < omap_dmm->num_lut; i++) {
>                 area.tcm = omap_dmm->tcm[i];
> --
> 1.7.5.4
>
> --
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