On Thu, Jul 26, 2018 at 07:44:06PM +0530, Mahesh Kumar wrote:
> This patch adds support to decode system memory bandwidth and other
> parameters for broxton platform, which will be used for arbitrated
> display memory bandwidth calculation in GEN9 based platforms and
> WM latency level-0 Work-around calculation on GEN9+ platforms.
>
> Changes since V1:
>  - s/memdev_info/dram_info
>
> Signed-off-by: Mahesh Kumar <mahesh1.ku...@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 116 
> ++++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_drv.h |  11 ++++
>  drivers/gpu/drm/i915/i915_reg.h |  30 +++++++++++
>  3 files changed, 157 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 18a45e7a3d7c..16629601c9f4 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1070,6 +1070,116 @@ static void intel_sanitize_options(struct 
> drm_i915_private *dev_priv)
>       intel_gvt_sanitize_options(dev_priv);
>  }
>
> +static int
> +bxt_get_dram_info(struct drm_i915_private *dev_priv)
> +{
> +     struct dram_info *dram_info = &dev_priv->dram_info;
> +     u32 dram_channels;
> +     u32 mem_freq_khz, val;
> +     u8 num_active_channels;
> +     int i;
> +
> +     val = I915_READ(BXT_P_CR_MC_BIOS_REQ_0_0_0);
> +     mem_freq_khz = DIV_ROUND_UP((val & BXT_REQ_DATA_MASK) *
> +                                 BXT_MEMORY_FREQ_MULTIPLIER_HZ, 1000);
> +
> +     dram_channels = (val >> BXT_DRAM_CHANNEL_ACTIVE_SHIFT) &
> +                                     BXT_DRAM_CHANNEL_ACTIVE_MASK;
> +     num_active_channels = hweight32(dram_channels);
> +
> +     /* Each active bit represents 4-byte channel */
> +     dram_info->bandwidth_kbps = (mem_freq_khz * num_active_channels * 4);
> +
> +     if (dram_info->bandwidth_kbps == 0) {
> +             DRM_INFO("Couldn't get system memory bandwidth\n");
> +             return -EINVAL;
> +     }
> +
> +     /*
> +      * Now read each DUNIT8/9/10/11 to check the rank of each dimms.
> +      */
> +     for (i = BXT_D_CR_DRP0_DUNIT_START; i <= BXT_D_CR_DRP0_DUNIT_END; i++) {
> +             u8 rank, size, width;
> +             enum dram_rank ch_rank;
> +
> +             val = I915_READ(BXT_D_CR_DRP0_DUNIT(i));
> +             if (val == 0xFFFFFFFF)
> +                     continue;
> +
> +             dram_info->num_channels++;
> +             rank = val & BXT_DRAM_RANK_MASK;
> +             width = (val >> BXT_DRAM_WIDTH_SHIFT) & BXT_DRAM_WIDTH_MASK;
> +             size = (val >> BXT_DRAM_SIZE_SHIFT) & BXT_DRAM_SIZE_MASK;
> +             if (rank == BXT_DRAM_RANK_SINGLE)
> +                     ch_rank = I915_DRAM_RANK_SINGLE;
> +             else if (rank == BXT_DRAM_RANK_DUAL)
> +                     ch_rank = I915_DRAM_RANK_DUAL;
> +             else
> +                     ch_rank = I915_DRAM_RANK_INVALID;
> +
> +             if (size == BXT_DRAM_SIZE_4GB)
> +                     size = 4;
> +             else if (size == BXT_DRAM_SIZE_6GB)
> +                     size = 6;
> +             else if (size == BXT_DRAM_SIZE_8GB)
> +                     size = 8;
> +             else if (size == BXT_DRAM_SIZE_12GB)
> +                     size = 12;
> +             else if (size == BXT_DRAM_SIZE_16GB)
> +                     size = 16;
> +             else
> +                     size = 0;
> +
> +             width = (1 << width) * 8;
> +             DRM_DEBUG_KMS("dram size:%dGB width:X%d rank:%s\n", size,
> +                           width, rank == BXT_DRAM_RANK_SINGLE ? "single" :
> +                           rank == BXT_DRAM_RANK_DUAL ? "dual" : "unknown");
> +
> +             /*
> +              * If any of the channel is single rank channel,
> +              * worst case output will be same as if single rank
> +              * memory, so consider single rank memory.
> +              */
> +             if (dram_info->rank == I915_DRAM_RANK_INVALID)
> +                     dram_info->rank = ch_rank;
> +             else if (ch_rank == I915_DRAM_RANK_SINGLE)
> +                     dram_info->rank = I915_DRAM_RANK_SINGLE;
> +     }
> +
> +     if (dram_info->rank == I915_DRAM_RANK_INVALID) {
> +             DRM_INFO("couldn't get memory rank information\n");
> +             return -EINVAL;
> +     }
> +
> +     dram_info->valid = true;
> +     return 0;
> +}
> +
> +static void
> +intel_get_dram_info(struct drm_i915_private *dev_priv)
> +{
> +     struct dram_info *dram_info = &dev_priv->dram_info;
> +     int ret;
> +
> +     dram_info->valid = false;
> +     dram_info->rank = I915_DRAM_RANK_INVALID;
> +     dram_info->bandwidth_kbps = 0;
> +     dram_info->num_channels = 0;
> +
> +     if (!IS_BROXTON(dev_priv))
> +             return;
> +
> +     ret = bxt_get_dram_info(dev_priv);
> +     if (ret)
> +             return;
> +
> +     DRM_DEBUG_KMS("DRAM bandwidth:%d KBps, total-channels: %u\n",
> +                   dram_info->bandwidth_kbps, dram_info->num_channels);
> +     DRM_DEBUG_KMS("DRAM rank: %s rank\n",
> +                   (dram_info->rank == I915_DRAM_RANK_DUAL) ?
> +                   "dual" : "single");
> +}
> +
>  /**
>   * i915_driver_init_hw - setup state requiring device access
>   * @dev_priv: device private
> @@ -1187,6 +1297,12 @@ static int i915_driver_init_hw(struct drm_i915_private 
> *dev_priv)
>               goto err_msi;
>
>       intel_opregion_setup(dev_priv);
> +     /*
> +      * Fill the dram structure to get the system raw bandwidth and
> +      * dram info. This will be used for memory latency calculation.
> +      */
> +     intel_get_dram_info(dev_priv);
> +
>
>       return 0;
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 0f49f9988dfa..46f942fa7d60 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1904,6 +1904,17 @@ struct drm_i915_private {
>               bool distrust_bios_wm;
>       } wm;
>
> +     struct dram_info {
> +             bool valid;
> +             u8 num_channels;
> +             enum dram_rank {
> +                     I915_DRAM_RANK_INVALID = 0,
> +                     I915_DRAM_RANK_SINGLE,
> +                     I915_DRAM_RANK_DUAL
> +             } rank;
> +             u32 bandwidth_kbps;
> +     } dram_info;
> +
>       struct i915_runtime_pm runtime_pm;
>
>       struct {
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 5530c470f30d..66900d027570 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -9634,6 +9634,36 @@ enum skl_power_gate {
>  #define  DC_STATE_DEBUG_MASK_CORES   (1 << 0)
>  #define  DC_STATE_DEBUG_MASK_MEMORY_UP       (1 << 1)
>
> +#define BXT_P_CR_MC_BIOS_REQ_0_0_0   _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x7114)
> +#define  BXT_REQ_DATA_MASK                   0x3F
> +#define  BXT_DRAM_CHANNEL_ACTIVE_SHIFT               12
> +#define  BXT_DRAM_CHANNEL_ACTIVE_MASK                0xF

Thanks a lot for the spec pointers. But now that I opened it and
started to reading here it was hard to review and I noticed this
is because the way that it is defined here doesn't respect our
standards as documented:

"
* For bit fields, define a ``_MASK`` and a ``_SHIFT`` macro. Define bit field
 * contents so that they are already shifted in place, and can be directly
 * OR'd.
"

So please provide a new version that follows the rules and
that it is easier to review. And sorry for not noticing this
on yesterday's review.

> +#define  BXT_MEMORY_FREQ_MULTIPLIER_HZ               133333333
> +
> +#define BXT_D_CR_DRP0_DUNIT8                 0x1000
> +#define BXT_D_CR_DRP0_DUNIT9                 0x1200
> +#define  BXT_D_CR_DRP0_DUNIT_START           8
> +#define  BXT_D_CR_DRP0_DUNIT_END             11
> +#define BXT_D_CR_DRP0_DUNIT(x)       _MMIO(MCHBAR_MIRROR_BASE_SNB + \
> +                                   _PICK_EVEN((x) - 8, BXT_D_CR_DRP0_DUNIT8,\
> +                                              BXT_D_CR_DRP0_DUNIT9))
> +#define  BXT_DRAM_RANK_MASK                  0x3
> +#define  BXT_DRAM_RANK_SINGLE                        0x1
> +#define  BXT_DRAM_RANK_DUAL                  0x3
> +#define  BXT_DRAM_WIDTH_MASK                 0x3
> +#define  BXT_DRAM_WIDTH_SHIFT                        4
> +#define  BXT_DRAM_WIDTH_X8                   0x0
> +#define  BXT_DRAM_WIDTH_X16                  0x1
> +#define  BXT_DRAM_WIDTH_X32                  0x2
> +#define  BXT_DRAM_WIDTH_X64                  0x3
> +#define  BXT_DRAM_SIZE_MASK                  0x7
> +#define  BXT_DRAM_SIZE_SHIFT                 6
> +#define  BXT_DRAM_SIZE_4GB                   0x0
> +#define  BXT_DRAM_SIZE_6GB                   0x1
> +#define  BXT_DRAM_SIZE_8GB                   0x2
> +#define  BXT_DRAM_SIZE_12GB                  0x3
> +#define  BXT_DRAM_SIZE_16GB                  0x4
> +
>  /* Please see hsw_read_dcomp() and hsw_write_dcomp() before using this 
> register,
>   * since on HSW we can't write to it using I915_WRITE. */
>  #define D_COMP_HSW                   _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5F0C)
> --
> 2.16.2
>
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