Re: [Freedreno] [PATCH v2 3/4] drm/msm: get rid of msm_iomap_size

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On Tue, 27 Apr 2021 at 22:30, <abhinavk@codeaurora.org> wrote:
>
> Hi Dmitry
>
> On 2021-04-26 17:18, Dmitry Baryshkov wrote:
> > Instead of looping throught the resources each time to get the DSI CTRL
> > area size, get it at the ioremap time.
> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> We will have to call into the individual modules anyway everytime we
> take a snapshot as only they have access to the required clocks and the
> base address.
>
> So even though there is nothing wrong with this change, it still adds a
> size member
> which can be avoided because we have to call into the module anyway.
>
> Any strong preference to store the size as opposed to just getting it
> when we take
> the snapshot?

Locality. We ioremap the resource from one piece of code and then we
get it's length from a completely different piece of code. If we ever
change e.g. the ioremap'ed resource name, we'd have to also update
snapshot users.
With this patch these changes are done in a transparent way. Whichever
we do with the regions in future, there is always a valid base + size
combo.

>
> > ---
> >  drivers/gpu/drm/msm/dsi/dsi_host.c |  5 +++--
> >  drivers/gpu/drm/msm/msm_drv.c      | 27 +++++++++------------------
> >  drivers/gpu/drm/msm/msm_drv.h      |  3 ++-
> >  3 files changed, 14 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > index 1a63368c3912..b3ee5c0bce12 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > @@ -102,6 +102,7 @@ struct msm_dsi_host {
> >       int id;
> >
> >       void __iomem *ctrl_base;
> > +     phys_addr_t ctrl_size;
> >       struct regulator_bulk_data supplies[DSI_DEV_REGULATOR_MAX];
> >
> >       struct clk *bus_clks[DSI_BUS_CLK_MAX];
> > @@ -1839,7 +1840,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
> >               goto fail;
> >       }
> >
> > -     msm_host->ctrl_base = msm_ioremap(pdev, "dsi_ctrl", "DSI CTRL");
> > +     msm_host->ctrl_base = msm_ioremap_size(pdev, "dsi_ctrl", "DSI CTRL",
> > &msm_host->ctrl_size);
> >       if (IS_ERR(msm_host->ctrl_base)) {
> >               pr_err("%s: unable to map Dsi ctrl base\n", __func__);
> >               ret = PTR_ERR(msm_host->ctrl_base);
> > @@ -2494,7 +2495,7 @@ void msm_dsi_host_snapshot(struct msm_disp_state
> > *disp_state, struct mipi_dsi_ho
> >
> >       pm_runtime_get_sync(&msm_host->pdev->dev);
> >
> > -     msm_disp_snapshot_add_block(disp_state,
> > msm_iomap_size(msm_host->pdev, "dsi_ctrl"),
> > +     msm_disp_snapshot_add_block(disp_state, msm_host->ctrl_size,
> >                       msm_host->ctrl_base, "dsi%d_ctrl", msm_host->id);
> >
> >       pm_runtime_put_sync(&msm_host->pdev->dev);
> > diff --git a/drivers/gpu/drm/msm/msm_drv.c
> > b/drivers/gpu/drm/msm/msm_drv.c
> > index 92fe844b517b..be578fc4e54f 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.c
> > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > @@ -124,7 +124,7 @@ struct clk *msm_clk_get(struct platform_device
> > *pdev, const char *name)
> >  }
> >
> >  static void __iomem *_msm_ioremap(struct platform_device *pdev, const
> > char *name,
> > -                               const char *dbgname, bool quiet)
> > +                               const char *dbgname, bool quiet, phys_addr_t *psize)
> >  {
> >       struct resource *res;
> >       unsigned long size;
> > @@ -153,37 +153,28 @@ static void __iomem *_msm_ioremap(struct
> > platform_device *pdev, const char *name
> >       if (reglog)
> >               printk(KERN_DEBUG "IO:region %s %p %08lx\n", dbgname, ptr, size);
> >
> > +     if (psize)
> > +             *psize = size;
> > +
> >       return ptr;
> >  }
> >
> >  void __iomem *msm_ioremap(struct platform_device *pdev, const char
> > *name,
> >                         const char *dbgname)
> >  {
> > -     return _msm_ioremap(pdev, name, dbgname, false);
> > +     return _msm_ioremap(pdev, name, dbgname, false, NULL);
> >  }
> >
> >  void __iomem *msm_ioremap_quiet(struct platform_device *pdev, const
> > char *name,
> >                               const char *dbgname)
> >  {
> > -     return _msm_ioremap(pdev, name, dbgname, true);
> > +     return _msm_ioremap(pdev, name, dbgname, true, NULL);
> >  }
> >
> > -unsigned long msm_iomap_size(struct platform_device *pdev, const char
> > *name)
> > +void __iomem *msm_ioremap_size(struct platform_device *pdev, const
> > char *name,
> > +                       const char *dbgname, phys_addr_t *psize)
> >  {
> > -     struct resource *res;
> > -
> > -     if (name)
> > -             res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
> > -     else
> > -             res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -
> > -     if (!res) {
> > -             dev_dbg(&pdev->dev, "failed to get memory resource: %s\n",
> > -                             name);
> > -             return 0;
> > -     }
> > -
> > -     return resource_size(res);
> > +     return _msm_ioremap(pdev, name, dbgname, false, psize);
> >  }
> >
> >  void msm_writel(u32 data, void __iomem *addr)
> > diff --git a/drivers/gpu/drm/msm/msm_drv.h
> > b/drivers/gpu/drm/msm/msm_drv.h
> > index 15cb34451ded..c33fc1293789 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.h
> > +++ b/drivers/gpu/drm/msm/msm_drv.h
> > @@ -450,9 +450,10 @@ struct clk *msm_clk_bulk_get_clock(struct
> > clk_bulk_data *bulk, int count,
> >       const char *name);
> >  void __iomem *msm_ioremap(struct platform_device *pdev, const char
> > *name,
> >               const char *dbgname);
> > +void __iomem *msm_ioremap_size(struct platform_device *pdev, const
> > char *name,
> > +             const char *dbgname, phys_addr_t *size);
> >  void __iomem *msm_ioremap_quiet(struct platform_device *pdev, const
> > char *name,
> >               const char *dbgname);
> > -unsigned long msm_iomap_size(struct platform_device *pdev, const char
> > *name);
> >  void msm_writel(u32 data, void __iomem *addr);
> >  u32 msm_readl(const void __iomem *addr);
> >  void msm_rmw(void __iomem *addr, u32 mask, u32 or);



-- 
With best wishes
Dmitry
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