Re: [PATCH] drm/i915/display: Convert i915_suspend into i9xx_display_sr

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Sep 13, 2024 at 02:22:34PM +0300, Ville Syrjälä wrote:
> On Thu, Sep 12, 2024 at 01:45:34PM -0400, Rodrigo Vivi wrote:
> > These save & restore functions inside i915_suspend are old display
> > functions to save and restore a bunch of display related registers.
> > 
> > Move it under display and rename accordantly. Just don't move it
> > entirely towards intel_display struct yet because it depends
> > on drm_i915_private for the IS_MOBILE.
> > 
> > While doing this conversion also update the MIT header using
> > the new SPDX ones.
> > 
> > Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > ---
> >  drivers/gpu/drm/i915/Makefile                 |   2 +-
> >  .../gpu/drm/i915/display/i9xx_display_sr.c    | 119 +++++++++++++++
> >  .../gpu/drm/i915/display/i9xx_display_sr.h    |  14 ++
> >  drivers/gpu/drm/i915/i915_driver.c            |   6 +-
> >  drivers/gpu/drm/i915/i915_suspend.c           | 141 ------------------
> >  drivers/gpu/drm/i915/i915_suspend.h           |  14 --
> >  6 files changed, 137 insertions(+), 159 deletions(-)
> >  create mode 100644 drivers/gpu/drm/i915/display/i9xx_display_sr.c
> >  create mode 100644 drivers/gpu/drm/i915/display/i9xx_display_sr.h
> >  delete mode 100644 drivers/gpu/drm/i915/i915_suspend.c
> >  delete mode 100644 drivers/gpu/drm/i915/i915_suspend.h
> > 
> > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> > index c63fa2133ccb..89f04bdbc27f 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -30,7 +30,6 @@ i915-y += \
> >  	i915_params.o \
> >  	i915_pci.o \
> >  	i915_scatterlist.o \
> > -	i915_suspend.o \
> >  	i915_switcheroo.o \
> >  	i915_sysfs.o \
> >  	i915_utils.o \
> > @@ -219,6 +218,7 @@ i915-$(CONFIG_HWMON) += \
> >  i915-y += \
> >  	display/hsw_ips.o \
> >  	display/i9xx_plane.o \
> > +	display/i9xx_suspend.o \
> >  	display/i9xx_wm.o \
> >  	display/intel_alpm.o \
> >  	display/intel_atomic.o \
> > diff --git a/drivers/gpu/drm/i915/display/i9xx_display_sr.c b/drivers/gpu/drm/i915/display/i9xx_display_sr.c
> > new file mode 100644
> > index 000000000000..211cf41119ad
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/i9xx_display_sr.c
> > @@ -0,0 +1,119 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2024 Intel Corporation
> > + */
> > +
> > +#include "i915_drv.h"
> > +#include "i915_reg.h"
> > +#include "i9xx_suspend.h"
> > +#include "intel_de.h"
> > +#include "intel_gmbus.h"
> > +#include "intel_vga.h"
> > +#include "intel_pci_config.h"
> > +
> > +static void intel_save_swf(struct drm_i915_private *i915)
> > +{
> > +	int i;
> > +
> > +	/* Scratch space */
> > +	if (DISPLAY_VER(i915) == 2 && IS_MOBILE(i915)) {
> > +		for (i = 0; i < 7; i++) {
> > +			i915->regfile.saveSWF0[i] = intel_de_read(i915,
> > +								      SWF0(i915, i));
> > +			i915->regfile.saveSWF1[i] = intel_de_read(i915,
> > +								      SWF1(i915, i));
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			i915->regfile.saveSWF3[i] = intel_de_read(i915,
> > +								      SWF3(i915, i));
> > +	} else if (DISPLAY_VER(i915) == 2) {
> > +		for (i = 0; i < 7; i++)
> > +			i915->regfile.saveSWF1[i] = intel_de_read(i915,
> > +								      SWF1(i915, i));
> > +	} else if (HAS_GMCH(i915)) {
> > +		for (i = 0; i < 16; i++) {
> > +			i915->regfile.saveSWF0[i] = intel_de_read(i915,
> > +								      SWF0(i915, i));
> > +			i915->regfile.saveSWF1[i] = intel_de_read(i915,
> > +								      SWF1(i915, i));
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			i915->regfile.saveSWF3[i] = intel_de_read(i915,
> > +								      SWF3(i915, i));
> > +	}
> > +}
> > +
> > +static void intel_restore_swf(struct drm_i915_private *i915)
> > +{
> > +	int i;
> > +
> > +	/* Scratch space */
> > +	if (DISPLAY_VER(i915) == 2 && IS_MOBILE(i915)) {
> > +		for (i = 0; i < 7; i++) {
> > +			intel_de_write(i915, SWF0(i915, i),
> > +				       i915->regfile.saveSWF0[i]);
> > +			intel_de_write(i915, SWF1(i915, i),
> > +				       i915->regfile.saveSWF1[i]);
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			intel_de_write(i915, SWF3(i915, i),
> > +				       i915->regfile.saveSWF3[i]);
> > +	} else if (DISPLAY_VER(i915) == 2) {
> > +		for (i = 0; i < 7; i++)
> > +			intel_de_write(i915, SWF1(i915, i),
> > +				       i915->regfile.saveSWF1[i]);
> > +	} else if (HAS_GMCH(i915)) {
> > +		for (i = 0; i < 16; i++) {
> > +			intel_de_write(i915, SWF0(i915, i),
> > +				       i915->regfile.saveSWF0[i]);
> > +			intel_de_write(i915, SWF1(i915, i),
> > +				       i915->regfile.saveSWF1[i]);
> > +		}
> > +		for (i = 0; i < 3; i++)
> > +			intel_de_write(i915, SWF3(i915, i),
> > +				       i915->regfile.saveSWF3[i]);
> > +	}
> > +}
> > +
> > +void i9xx_display_sr_save(struct drm_i915_private *i915)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> > +
> > +	if (!HAS_DISPLAY(i915))
> > +		return;
> > +
> > +	/* Display arbitration control */
> > +	if (DISPLAY_VER(i915) <= 4)
> > +		i915->regfile.saveDSPARB = intel_de_read(i915,
> > +							     DSPARB(i915));
> > +
> > +	if (DISPLAY_VER(i915) == 4)
> > +		pci_read_config_word(pdev, GCDGMBUS,
> > +				     &i915->regfile.saveGCDGMBUS);
> > +
> > +	intel_save_swf(i915);
> > +}
> > +
> > +void i9xx_display_sr_restore(struct drm_i915_private *i915)
> > +{
> > +	struct intel_display *display = &i915->display;
> > +	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> > +
> > +	if (!HAS_DISPLAY(i915))
> > +		return;
> > +
> > +	intel_restore_swf(i915);
> > +
> > +	if (DISPLAY_VER(i915) == 4)
> > +		pci_write_config_word(pdev, GCDGMBUS,
> > +				      i915->regfile.saveGCDGMBUS);
> > +
> > +	/* Display arbitration */
> > +	if (DISPLAY_VER(i915) <= 4)
> > +		intel_de_write(i915, DSPARB(i915),
> > +			       i915->regfile.saveDSPARB);
> > +
> > +	intel_vga_redisable(display);
> > +
> > +	intel_gmbus_reset(i915);
> 
> The last two are for all platforms, so the function name is a bit
> misleading now.

Indeed... having another patch to remove this from this function
before the name conversion.

> 
> Also we might want to do the SWF save/restore for all platforms
> as well, because technically we should be reading one of those
> to determine the maximum CDCLK for the system (if the BIOS
> has chosen a limit other than the platform default). We could
> get into trouble there if the driver is reloaded after S3,
> assuming S3 clobbers the SWF registers (which I'm not 100%
> sure it does, would need to confirm it).

Well, if we end up needing that we can always do a s/i9xx/i915
later in the name. But I really don't believe that we should
be the ones taking care of the registers save/restore. Some
one else should be taking care of this save restore, or we should
simply stash the boot value.

> 
> I have an old branch that does the SWF read for BDW only
> 'https://github.com/vsyrjala/linux.git bdw_vbios_cdclk_limit'
> but last I looked Windows was still doing this for all
> platforms, so we should probably we doing the same.
> 
> -- 
> Ville Syrjälä
> Intel