[PATCH] [V3] Xilinx : Framebuffer Driver: Add PLB support and cleanup DCR

Grant Likely grant.likely at secretlab.ca
Thu Apr 16 01:14:41 EST 2009


On Tue, Apr 14, 2009 at 2:08 PM, John Linn <john.linn at xilinx.com> wrote:
> Added support for the new xps tft controller. The new core
> has PLB interface support in addition to existing DCR interface.

Good looking patch.  A few more comments below.

g.

>  /*
>  * Xilinx calls it "PLB TFT LCD Controller" though it can also be used for
> - * the VGA port on the Xilinx ML40x board. This is a hardware display controller
> - * for a 640x480 resolution TFT or VGA screen.
> + * the VGA port on the Xilinx ML40x board. This is a hardware display
> + * controller for a 640x480 resolution TFT or VGA screen.

This isn't necessarily true.  This driver will handle controllers
using different resolutions (I know, I know, this is just cleaning up
an existing comment, but no need to leave inaccuracies in there)  :-)

> -#define xilinx_fb_out_be32(driverdata, offset, val) \
> -       out_be32(driverdata->regs + offset, val)
> +static void xilinx_fb_out_be32(struct xilinxfb_drvdata *drvdata, u32 offset,
> +                               u32 val)
> +{
> +       if (drvdata->flags & PLB_ACCESS_FLAG)
> +               out_be32(drvdata->regs + (offset << 2), val);
> +       else
> +               dcr_write(drvdata->dcr_host, offset, val);
> +

This could more simply be:

        if (drvdata->regs)
                out_be32(drvdata->regs + (offset << 2), val);
        else
                dcr_write(drvdata->dcr_host, offset, val);

regs will be NULL if DCR is active.

> -static int xilinxfb_assign(struct device *dev, unsigned long physaddr,
> +static int xilinxfb_assign(struct device *dev,
> +                          struct xilinxfb_drvdata *drvdata,
> +                          unsigned long physaddr,
>                           struct xilinxfb_platform_data *pdata)
>  {
> -       struct xilinxfb_drvdata *drvdata;
>        int rc;
>        int fbsize = pdata->xvirt * pdata->yvirt * BYTES_PER_PIXEL;
>
> -       /* Allocate the driver data region */
> -       drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
> -       if (!drvdata) {
> -               dev_err(dev, "Couldn't allocate device private record\n");
> -               return -ENOMEM;
> -       }
> -       dev_set_drvdata(dev, drvdata);
> -
> -       /* Map the control registers in */
> -       if (!request_mem_region(physaddr, 8, DRIVER_NAME)) {
> -               dev_err(dev, "Couldn't lock memory region at 0x%08lX\n",
> -                       physaddr);
> -               rc = -ENODEV;
> -               goto err_region;
> -       }
> -       drvdata->regs_phys = physaddr;
> -       drvdata->regs = ioremap(physaddr, 8);
> -       if (!drvdata->regs) {
> -               dev_err(dev, "Couldn't lock memory region at 0x%08lX\n",
> -                       physaddr);
> -               rc = -ENODEV;
> -               goto err_map;
> +       if (drvdata->flags & PLB_ACCESS_FLAG) {

Again, I think using "if (physaddr) {" would be simpler and make more
sense and would eliminate even needing a flags data member.

> +               /*
> +                * Map the control registers in if the controller
> +                * is on direct PLB interface.
> +                */
> +               if (!request_mem_region(physaddr, 8, DRIVER_NAME)) {
> +                       dev_err(dev, "Couldn't lock memory region at 0x%08lX\n",
> +                               physaddr);
> +                       rc = -ENODEV;
> +                       goto err_region;
> +               }
> +
> +               drvdata->regs_phys = physaddr;
> +               drvdata->regs = ioremap(physaddr, 8);
> +               if (!drvdata->regs) {
> +                       dev_err(dev, "Couldn't lock memory region at 0x%08lX\n",
> +                               physaddr);
> +                       rc = -ENODEV;
> +                       goto err_map;
> +               }
>        }
>
>        /* Allocate the framebuffer memory */
> @@ -247,7 +267,10 @@ static int xilinxfb_assign(struct device *dev, unsigned long physaddr,
>        if (!drvdata->fb_virt) {
>                dev_err(dev, "Could not allocate frame buffer memory\n");
>                rc = -ENOMEM;
> -               goto err_fbmem;
> +               if (drvdata->flags & PLB_ACCESS_FLAG)
> +                       goto err_fbmem;
> +               else
> +                       goto err_region;

This change doesn't make much sense because the same condition is
tested for again at the err_fbmem: label.  To avoid confusion later
on, keep the unwind path simple (don't jump to different labels).

>        }
>
>        /* Clear (turn to black) the framebuffer */
> @@ -260,7 +283,8 @@ static int xilinxfb_assign(struct device *dev, unsigned long physaddr,
>        drvdata->reg_ctrl_default = REG_CTRL_ENABLE;
>        if (pdata->rotate_screen)
>                drvdata->reg_ctrl_default |= REG_CTRL_ROTATE;
> -       xilinx_fb_out_be32(drvdata, REG_CTRL, drvdata->reg_ctrl_default);
> +       xilinx_fb_out_be32(drvdata, REG_CTRL,
> +                                       drvdata->reg_ctrl_default);
>
>        /* Fill struct fb_info */
>        drvdata->info.device = dev;
> @@ -296,11 +320,14 @@ static int xilinxfb_assign(struct device *dev, unsigned long physaddr,
>                goto err_regfb;
>        }
>
> +       if (drvdata->flags & PLB_ACCESS_FLAG) {

if (drvdata->regs) {

> +               /* Put a banner in the log (for DEBUG) */
> +               dev_dbg(dev, "regs: phys=%lx, virt=%p\n", physaddr,
> +                                       drvdata->regs);
> +       }
>        /* Put a banner in the log (for DEBUG) */
> -       dev_dbg(dev, "regs: phys=%lx, virt=%p\n", physaddr, drvdata->regs);
> -       dev_dbg(dev, "fb: phys=%llx, virt=%p, size=%x\n",
> -               (unsigned long long) drvdata->fb_phys, drvdata->fb_virt,
> -               fbsize);
> +       dev_dbg(dev, "fb: phys=%p, virt=%p, size=%x\n",
> +               (void *)drvdata->fb_phys, drvdata->fb_virt, fbsize);
>
>        return 0;       /* success */
>
> @@ -311,14 +338,19 @@ err_cmap:
>        if (drvdata->fb_alloced)
>                dma_free_coherent(dev, PAGE_ALIGN(fbsize), drvdata->fb_virt,
>                        drvdata->fb_phys);
> +       else
> +               iounmap(drvdata->fb_virt);
> +
>        /* Turn off the display */
>        xilinx_fb_out_be32(drvdata, REG_CTRL, 0);
>
>  err_fbmem:
> -       iounmap(drvdata->regs);
> +       if (drvdata->flags & PLB_ACCESS_FLAG)
> +               iounmap(drvdata->regs);

if (drvdata->regs)

>
>  err_map:
> -       release_mem_region(physaddr, 8);
> +       if (drvdata->flags & PLB_ACCESS_FLAG)
> +               release_mem_region(physaddr, 8);

if (physaddr)

>
>  err_region:
>        kfree(drvdata);
> @@ -342,12 +374,18 @@ static int xilinxfb_release(struct device *dev)
>        if (drvdata->fb_alloced)
>                dma_free_coherent(dev, PAGE_ALIGN(drvdata->info.fix.smem_len),
>                                  drvdata->fb_virt, drvdata->fb_phys);
> +       else
> +               iounmap(drvdata->fb_virt);
>
>        /* Turn off the display */
>        xilinx_fb_out_be32(drvdata, REG_CTRL, 0);
> -       iounmap(drvdata->regs);
>
> -       release_mem_region(drvdata->regs_phys, 8);
> +       /* Release the resources, as allocated based on interface */
> +       if (drvdata->flags & PLB_ACCESS_FLAG) {
> +               iounmap(drvdata->regs);
> +               release_mem_region(drvdata->regs_phys, 8);
> +       } else
> +               dcr_unmap(drvdata->dcr_host, drvdata->dcr_len);

et cetera

> -#if defined(CONFIG_OF)
>  static int __devinit
>  xilinxfb_of_probe(struct of_device *op, const struct of_device_id *match)
>  {
> -       struct resource res;
>        const u32 *prop;
> +       u32 *p;
> +       u32 tft_access;
>        struct xilinxfb_platform_data pdata;
> +       struct resource res;
>        int size, rc;
> +       int start = 0, len = 0;
> +       dcr_host_t dcr_host;
> +       struct xilinxfb_drvdata *drvdata;
>
>        /* Copy with the default pdata (not a ptr reference!) */
>        pdata = xilinx_fb_default_pdata;
>
>        dev_dbg(&op->dev, "xilinxfb_of_probe(%p, %p)\n", op, match);
>
> -       rc = of_address_to_resource(op->node, 0, &res);
> -       if (rc) {
> -               dev_err(&op->dev, "invalid address\n");
> -               return rc;
> +       /*
> +        * To check whether the core is connected directly to DCR or PLB
> +        * interface and initialize the tft_access accordingly.
> +        */
> +       p = (u32 *)of_get_property(op->node, "xlnx,dcr-splb-slave-if", NULL);

Hmmm.  This binding is undocumented.  It would be better to make the
decision on the presence/absence of the dcr-reg and/or reg properties.

> +
> +       if (p)
> +               tft_access = *p;
> +       else
> +               tft_access = 0;         /* For backward compatibility */

Common pattern: tft_access = p ? *p : 0;

> +
> +       /*
> +        * Fill the resource structure if its direct PLB interface
> +        * otherwise fill the dcr_host structure.
> +        */
> +       if (tft_access) {
> +               rc = of_address_to_resource(op->node, 0, &res);
> +               if (rc) {
> +                       dev_err(&op->dev, "invalid address\n");
> +                       return -ENODEV;
> +               }
> +
> +       } else {
> +               start = dcr_resource_start(op->node, 0);
> +               len = dcr_resource_len(op->node, 0);
> +               dcr_host = dcr_map(op->node, start, len);
> +               if (!DCR_MAP_OK(dcr_host)) {
> +                       dev_err(&op->dev, "invalid address\n");
> +                       return -ENODEV;
> +               }
>        }
>
>        prop = of_get_property(op->node, "phys-size", &size);
> @@ -450,7 +468,26 @@ xilinxfb_of_probe(struct of_device *op, const struct of_device_id *match)
>        if (of_find_property(op->node, "rotate-display", NULL))
>                pdata.rotate_screen = 1;
>
> -       return xilinxfb_assign(&op->dev, res.start, &pdata);
> +       /* Allocate the driver data region */
> +       drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
> +       if (!drvdata) {
> +               dev_err(&op->dev, "Couldn't allocate device private record\n");
> +               return -ENOMEM;
> +       }
> +       dev_set_drvdata(&op->dev, drvdata);
> +
> +       if (tft_access)
> +               drvdata->flags |= PLB_ACCESS_FLAG;
> +
> +       /* Arguments are passed based on the interface */
> +       if (drvdata->flags & PLB_ACCESS_FLAG) {
> +               return xilinxfb_assign(&op->dev, drvdata, res.start, &pdata);
> +       } else {
> +               drvdata->dcr_start = start;
> +               drvdata->dcr_len = len;
> +               drvdata->dcr_host = dcr_host;
> +               return xilinxfb_assign(&op->dev, drvdata, 0, &pdata);
> +       }
>  }
>
>  static int __devexit xilinxfb_of_remove(struct of_device *op)
> @@ -460,7 +497,9 @@ static int __devexit xilinxfb_of_remove(struct of_device *op)
>
>  /* Match table for of_platform binding */
>  static struct of_device_id xilinxfb_of_match[] __devinitdata = {
> +       { .compatible = "xlnx,xps-tft-1.00.a", },
>        { .compatible = "xlnx,plb-tft-cntlr-ref-1.00.a", },
> +       { .compatible = "xlnx,plb-dvi-cntlr-ref-1.00.c", },
>        {},
>  };
>  MODULE_DEVICE_TABLE(of, xilinxfb_of_match);
> @@ -476,22 +515,6 @@ static struct of_platform_driver xilinxfb_of_driver = {
>        },
>  };
>
> -/* Registration helpers to keep the number of #ifdefs to a minimum */
> -static inline int __init xilinxfb_of_register(void)
> -{
> -       pr_debug("xilinxfb: calling of_register_platform_driver()\n");
> -       return of_register_platform_driver(&xilinxfb_of_driver);
> -}
> -
> -static inline void __exit xilinxfb_of_unregister(void)
> -{
> -       of_unregister_platform_driver(&xilinxfb_of_driver);
> -}
> -#else /* CONFIG_OF */
> -/* CONFIG_OF not enabled; do nothing helpers */
> -static inline int __init xilinxfb_of_register(void) { return 0; }
> -static inline void __exit xilinxfb_of_unregister(void) { }
> -#endif /* CONFIG_OF */
>
>  /* ---------------------------------------------------------------------
>  * Module setup and teardown
> @@ -500,28 +523,18 @@ static inline void __exit xilinxfb_of_unregister(void) { }
>  static int __init
>  xilinxfb_init(void)
>  {
> -       int rc;
> -       rc = xilinxfb_of_register();
> -       if (rc)
> -               return rc;
> -
> -       rc = platform_driver_register(&xilinxfb_platform_driver);
> -       if (rc)
> -               xilinxfb_of_unregister();
> -
> -       return rc;
> +       return of_register_platform_driver(&xilinxfb_of_driver);
>  }
>
>  static void __exit
>  xilinxfb_cleanup(void)
>  {
> -       platform_driver_unregister(&xilinxfb_platform_driver);
> -       xilinxfb_of_unregister();
> +       of_unregister_platform_driver(&xilinxfb_of_driver);
>  }
>
>  module_init(xilinxfb_init);
>  module_exit(xilinxfb_cleanup);
>
>  MODULE_AUTHOR("MontaVista Software, Inc. <source at mvista.com>");
> -MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
> +MODULE_DESCRIPTION("Xilinx TFT frame buffer driver");
>  MODULE_LICENSE("GPL");
> --
> 1.6.2.1
>
>
>
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-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.



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