Re: [Intel-gfx] [PATCH v2] drm/i915/dg1: Read OPROM via SPI controller

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 15 Dec 2021, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> From: Clint Taylor <clinton.a.taylor@intel.com>
>
> Read OPROM SPI through MMIO and find VBT entry since we can't use
> OpRegion and PCI mapping may not work on some systems due to most BIOSes
> not leaving the Option ROM mapped.
>
> v2: Remove message with allocation failure
>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Tomas Winkler <tomas.winkler@intel.com>
> Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Acked-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_bios.c | 77 +++++++++++++++++++++--
>  drivers/gpu/drm/i915/i915_reg.h           |  8 +++
>  2 files changed, 79 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 9d989c9f5da4..76a8f001f4c4 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2335,6 +2335,63 @@ bool intel_bios_is_valid_vbt(const void *buf, size_t size)
>  	return vbt;
>  }
>  
> +static struct vbt_header *spi_oprom_get_vbt(struct drm_i915_private *i915)
> +{
> +	u32 count, data, found, store = 0;
> +	u32 static_region, oprom_offset;
> +	u32 oprom_size = 0x200000;
> +	u16 vbt_size;
> +	u32 *vbt;
> +
> +	static_region = intel_uncore_read(&i915->uncore, SPI_STATIC_REGIONS);
> +	static_region &= OPTIONROM_SPI_REGIONID_MASK;
> +	intel_uncore_write(&i915->uncore, PRIMARY_SPI_REGIONID, static_region);
> +
> +	oprom_offset = intel_uncore_read(&i915->uncore, OROM_OFFSET);
> +	oprom_offset &= OROM_OFFSET_MASK;
> +
> +	for (count = 0; count < oprom_size; count += 4) {
> +		intel_uncore_write(&i915->uncore, PRIMARY_SPI_ADDRESS, oprom_offset + count);
> +		data = intel_uncore_read(&i915->uncore, PRIMARY_SPI_TRIGGER);
> +
> +		if (data == *((const u32 *)"$VBT")) {
> +			found = oprom_offset + count;
> +			break;
> +		}
> +	}
> +
> +	if (count >= oprom_size)
> +		goto err_not_found;
> +
> +	/* Get VBT size and allocate space for the VBT */
> +	intel_uncore_write(&i915->uncore, PRIMARY_SPI_ADDRESS, found +
> +		   offsetof(struct vbt_header, vbt_size));
> +	vbt_size = intel_uncore_read(&i915->uncore, PRIMARY_SPI_TRIGGER);
> +	vbt_size &= 0xffff;
> +
> +	vbt = kzalloc(vbt_size, GFP_KERNEL);
> +	if (!vbt)
> +		goto err_not_found;
> +
> +	for (count = 0; count < vbt_size; count += 4) {
> +		intel_uncore_write(&i915->uncore, PRIMARY_SPI_ADDRESS, found + count);
> +		data = intel_uncore_read(&i915->uncore, PRIMARY_SPI_TRIGGER);
> +		*(vbt + store++) = data;
> +	}
> +
> +	if (!intel_bios_is_valid_vbt(vbt, vbt_size))
> +		goto err_free_vbt;
> +
> +	drm_dbg_kms(&i915->drm, "Found valid VBT in SPI flash\n");
> +
> +	return (struct vbt_header *)vbt;
> +
> +err_free_vbt:
> +	kfree(vbt);
> +err_not_found:
> +	return NULL;
> +}
> +
>  static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>  {
>  	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> @@ -2384,6 +2441,8 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
>  
>  	pci_unmap_rom(pdev, oprom);
>  
> +	drm_dbg_kms(&i915->drm, "Found valid VBT in PCI ROM\n");
> +
>  	return vbt;
>  
>  err_free_vbt:
> @@ -2418,17 +2477,23 @@ void intel_bios_init(struct drm_i915_private *i915)
>  
>  	init_vbt_defaults(i915);
>  
> -	/* If the OpRegion does not have VBT, look in PCI ROM. */
> +	/*
> +	 * If the OpRegion does not have VBT, look in SPI flash through MMIO or
> +	 * PCI mapping
> +	 */
> +	if (!vbt && IS_DGFX(i915)) {
> +		oprom_vbt = spi_oprom_get_vbt(i915);
> +		vbt = oprom_vbt;
> +	}
> +
>  	if (!vbt) {
>  		oprom_vbt = oprom_get_vbt(i915);
> -		if (!oprom_vbt)
> -			goto out;
> -
>  		vbt = oprom_vbt;
> -
> -		drm_dbg_kms(&i915->drm, "Found valid VBT in PCI ROM\n");
>  	}
>  
> +	if (!vbt)
> +		goto out;
> +
>  	bdb = get_bdb_header(vbt);
>  	i915->vbt.version = bdb->version;
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 698a023e70f5..3240b3eb1ddd 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -12974,6 +12974,14 @@ enum skl_power_gate {
>  #define  TCSS_DDI_STATUS_HPD_LIVE_STATUS_TBT	REG_BIT(1)
>  #define  TCSS_DDI_STATUS_HPD_LIVE_STATUS_ALT	REG_BIT(0)
>  
> +#define PRIMARY_SPI_TRIGGER			_MMIO(0x102040)
> +#define PRIMARY_SPI_ADDRESS			_MMIO(0x102080)
> +#define PRIMARY_SPI_REGIONID			_MMIO(0x102084)
> +#define SPI_STATIC_REGIONS			_MMIO(0x102090)
> +#define   OPTIONROM_SPI_REGIONID_MASK		REG_GENMASK(7, 0)
> +#define OROM_OFFSET				_MMIO(0x1020c0)
> +#define   OROM_OFFSET_MASK			REG_GENMASK(20, 16)
> +
>  /* This register controls the Display State Buffer (DSB) engines. */
>  #define _DSBSL_INSTANCE_BASE		0x70B00
>  #define DSBSL_INSTANCE(pipe, id)	(_DSBSL_INSTANCE_BASE + \

-- 
Jani Nikula, Intel Open Source Graphics Center