[PATCH v2 05/11] drm/msm: adreno: add plumbing to generate bandwidth vote table for GMU
neil.armstrong at linaro.org
neil.armstrong at linaro.org
Wed Nov 27 15:47:14 UTC 2024
On 27/11/2024 16:29, Akhil P Oommen wrote:
> On 11/25/2024 1:42 PM, Neil Armstrong wrote:
>> On 23/11/2024 23:46, Akhil P Oommen wrote:
>>> On Sun, Nov 24, 2024 at 02:52:46AM +0530, Akhil P Oommen wrote:
>>>> On Tue, Nov 19, 2024 at 06:56:40PM +0100, Neil Armstrong wrote:
>>>>> The Adreno GMU Management Unit (GMU) can also scale DDR Bandwidth along
>>>>> the Frequency and Power Domain level, but by default we leave the
>>>>> OPP core scale the interconnect ddr path.
>>>>>
>>>>> In order to calculate vote values used by the GPU Management
>>>>> Unit (GMU), we need to parse all the possible OPP Bandwidths and
>>>>
>>>> GMU expects a table of votes for each DDR frequency corners. Can we
>>>> please try to figure out a way to do that? Generally, we should
>>>> ensure the
>>>> data that is send to GMU firmware match downstream exactly. Because,
>>>> when something breaks in firmware or worst, at SoC level, it will be
>>>> pretty
>>>> hard to narrow down the issue. So, I prefer to be very conservative
>>>> about
>>>> this.
>>>>
>>>> KGSL keeps the ddr frequency table in the devicetree. That helps to keep
>>>> the driver lean, but I am not sure if that is viable upstream.
>>
>> No it's not, opp table is here for that, and we can reproduce the same
>> bahaviour by parsing all the bandwidths in the opp table.
>>
>>>>
>>>> -Akhil.
>>>>
>>>>> create a vote value to be sent to the appropriate Bus Control
>>>>> Modules (BCMs) declared in the GPU info struct.
>>>>>
>>>>> The vote array will then be used to dynamically generate the GMU
>>>>> bw_table sent during the GMU power-up.
>>>>>
>>>>> Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
>>>>> ---
>>>>> drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 153 ++++++++++++++++++++++
>>>>> ++++++++++++
>>>>> drivers/gpu/drm/msm/adreno/a6xx_gmu.h | 14 ++++
>>>>> drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 1 +
>>>>> 3 files changed, 168 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/
>>>>> drm/msm/adreno/a6xx_gmu.c
>>>>> index
>>>>> 14db7376c712d19446b38152e480bd5a1e0a5198..f6814d92a4edb29ba8a34a34aabb8b2324e9c6a4 100644
>>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
>>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
>>>>> @@ -9,6 +9,7 @@
>>>>> #include <linux/pm_domain.h>
>>>>> #include <linux/pm_opp.h>
>>>>> #include <soc/qcom/cmd-db.h>
>>>>> +#include <soc/qcom/tcs.h>
>>>>> #include <drm/drm_gem.h>
>>>>> #include "a6xx_gpu.h"
>>>>> @@ -1287,6 +1288,109 @@ static int a6xx_gmu_memory_probe(struct
>>>>> a6xx_gmu *gmu)
>>>>> return 0;
>>>>> }
>>>>> +/**
>>>>> + * struct bcm_db - Auxiliary data pertaining to each Bus Clock
>>>>> Manager (BCM)
>>>>> + * @unit: divisor used to convert bytes/sec bw value to an RPMh msg
>>>>> + * @width: multiplier used to convert bytes/sec bw value to an RPMh
>>>>> msg
>>>>> + * @vcd: virtual clock domain that this bcm belongs to
>>>>> + * @reserved: reserved field
>>>>> + */
>>>>> +struct bcm_db {
>>>>> + __le32 unit;
>>>>> + __le16 width;
>>>>> + u8 vcd;
>>>>> + u8 reserved;
>>>>> +};
>>>
>>> Shouldn't this be a packed struct? It is naturally aligned, but still!
>>
>> It's used as-is in the interconnecty driver, so I assume it's fine.
>>
>>>
>>>>> +
>>>>> +static u64 bcm_div(u64 num, u32 base)
>>>>> +{
>>>>> + /* Ensure that small votes aren't lost. */
>>>>> + if (num && num < base)
>>>>> + return 1;
>>>>> +
>>>>> + do_div(num, base);
>>>>> +
>>>>> + return num;
>>>>> +}
>>>>> +
>>>>> +static int a6xx_gmu_rpmh_bw_votes_init(const struct a6xx_info *info,
>>>>> + struct a6xx_gmu *gmu)
>>>>> +{
>>>>> + const struct bcm_db *bcm_data[GMU_MAX_BCMS] = { 0 };
>>>>> + unsigned int bcm_index, bw_index;
>>>>> +
>>>>> + /* Retrieve BCM data from cmd-db */
>>>>> + for (bcm_index = 0; bcm_index < GMU_MAX_BCMS; bcm_index++) {
>>>>> + size_t count;
>>>>> +
>>>>> + /* Skip unconfigured BCM */
>>>>> + if (!info->bcm[bcm_index].name)
>>>>> + continue;
>>>>> +
>>>>> + bcm_data[bcm_index] = cmd_db_read_aux_data(
>>>>> + info->bcm[bcm_index].name,
>>>>> + &count);
>>>>> + if (IS_ERR(bcm_data[bcm_index]))
>>>>> + return PTR_ERR(bcm_data[bcm_index]);
>>>>> +
>>>>> + if (!count)
>>>>> + return -EINVAL;
>>>>> + }
>>>>> +
>>>>> + /* Generate BCM votes values for each bandwidth & BCM */
>>>>> + for (bw_index = 0; bw_index < gmu->nr_gpu_bws; bw_index++) {
>>>>> + u32 *data = gmu->gpu_bw_votes[bw_index];
>>>>> + u32 bw = gmu->gpu_bw_table[bw_index];
>>>>> +
>>>>> + /* Calculations loosely copied from bcm_aggregate() &
>>>>> tcs_cmd_gen() */
>>>>> + for (bcm_index = 0; bcm_index < GMU_MAX_BCMS; bcm_index++) {
>>>>> + bool commit = false;
>>>>> + u64 peak, vote;
>>>>> + u16 width;
>>>>> + u32 unit;
>>>>> +
>>>>> + /* Skip unconfigured BCM */
>>>>> + if (!info->bcm[bcm_index].name || !bcm_data[bcm_index])
>>>>> + continue;
>>>>> +
>>>>> + if (bcm_index == GMU_MAX_BCMS - 1 ||
>>>>> + (bcm_data[bcm_index + 1] &&
>>>>> + bcm_data[bcm_index]->vcd != bcm_data[bcm_index +
>>>>> 1]->vcd))
>>>>> + commit = true;
>>>>> +
>>>>> + if (!bw) {
>>>>> + data[bcm_index] = BCM_TCS_CMD(commit, false, 0, 0);
>>>>> + continue;
>>>>> + }
>>>>> +
>>>>> + if (info->bcm[bcm_index].fixed) {
>>>>> + u32 perfmode = 0;
>>>>> +
>>>>> + if (bw >= info->bcm[bcm_index].perfmode_bw)
>>>>> + perfmode = info->bcm[bcm_index].perfmode;
>>>>> +
>>>>> + data[bcm_index] = BCM_TCS_CMD(commit, true, 0,
>>>>> perfmode);
>>>>> + continue;
>>>>> + }
>>>>> +
>>>>> + /* Multiply the bandwidth by the width of the
>>>>> connection */
>>>>> + width = le16_to_cpu(bcm_data[bcm_index]->width);
>>>>> + peak = bcm_div((u64)bw * width, info-
>>>>>> bcm[bcm_index].buswidth);
>>>>> +
>>>>> + /* Input bandwidth value is in KBps, scale the value to
>>>>> BCM unit */
>>>>> + unit = le32_to_cpu(bcm_data[bcm_index]->unit);
>>>>> + vote = bcm_div(peak * 1000ULL, unit);
>>>>> +
>>>>> + if (vote > BCM_TCS_CMD_VOTE_MASK)
>>>>> + vote = BCM_TCS_CMD_VOTE_MASK;
>>>>> +
>>>>> + data[bcm_index] = BCM_TCS_CMD(commit, true, vote, vote);
>>>>> + }
>>>>> + }
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> /* Return the 'arc-level' for the given frequency */
>>>>> static unsigned int a6xx_gmu_get_arc_level(struct device *dev,
>>>>> unsigned long freq)
>>>>> @@ -1390,12 +1494,15 @@ static int
>>>>> a6xx_gmu_rpmh_arc_votes_init(struct device *dev, u32 *votes,
>>>>> * The GMU votes with the RPMh for itself and on behalf of the GPU
>>>>> but we need
>>>>> * to construct the list of votes on the CPU and send it over.
>>>>> Query the RPMh
>>>>> * voltage levels and build the votes
>>>>> + * The GMU can also vote for DDR interconnects, use the OPP
>>>>> bandwidth entries
>>>>> + * and BCM parameters to build the votes.
>>>>> */
>>>>> static int a6xx_gmu_rpmh_votes_init(struct a6xx_gmu *gmu)
>>>>> {
>>>>> struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu,
>>>>> gmu);
>>>>> struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
>>>>> + const struct a6xx_info *info = adreno_gpu->info->a6xx;
>>>>> struct msm_gpu *gpu = &adreno_gpu->base;
>>>>> int ret;
>>>>> @@ -1407,6 +1514,10 @@ static int a6xx_gmu_rpmh_votes_init(struct
>>>>> a6xx_gmu *gmu)
>>>>> ret |= a6xx_gmu_rpmh_arc_votes_init(gmu->dev, gmu->cx_arc_votes,
>>>>> gmu->gmu_freqs, gmu->nr_gmu_freqs, "cx.lvl");
>>>>> + /* Build the interconnect votes */
>>>>> + if (adreno_gpu->info->features & ADRENO_FEAT_GMU_BW_VOTE)
>>>>> + ret |= a6xx_gmu_rpmh_bw_votes_init(info, gmu);
>>>>> +
>>>>> return ret;
>>>>> }
>>>>> @@ -1442,6 +1553,38 @@ static int a6xx_gmu_build_freq_table(struct
>>>>> device *dev, unsigned long *freqs,
>>>>> return index;
>>>>> }
>>>>> +static int a6xx_gmu_build_bw_table(struct device *dev, unsigned
>>>>> long *bandwidths,
>>>>> + u32 size)
>>>>> +{
>>>>> + int count = dev_pm_opp_get_opp_count(dev);
>>>
>>> I suppose this doesn't count the opps which are not supported by the
>>> SKU. If we can go through *all* OPPs in the opp table irrespective of
>>> the SKU, we will get something close to a full DDR bw table I mentioned
>>> in the prevous mail.
>>
>> It parses _all_ bandwitdh declared in the opp table, without any discard,
>> so yes we're close to a full DDR table. It only lacks a few low bandwidths.
>>
> Isn't opp_table->opp_list created after filtering with supported_hw bitmask?
Sure, but opp filtering is not supported on a7xx, and nevetheless only
the high OPPs would be filtered out, so I don't understand why it would matter ?
As of today, the gx_arc_votes are already constructed the exact same way
I build the BW vote table, so why the BW table should be the ____exact____
same as downstream while we don't care about the gx_arc_votes ?
Neil
>
> -Akhil.
>>>
>>>>> + struct dev_pm_opp *opp;
>>>>> + int i, index = 0;
>>>>> + unsigned int bandwidth = 1;
>>>>> +
>>>>> + /*
>>>>> + * The OPP table doesn't contain the "off" bandwidth level so
>>>>> we need to
>>>>> + * add 1 to the table size to account for it
>>>>> + */
>>>>> +
>>>>> + if (WARN(count + 1 > size,
>>>>> + "The GMU bandwidth table is being truncated\n"))
>>>>> + count = size - 1;
>>>>> +
>>>>> + /* Set the "off" bandwidth */
>>>>> + bandwidths[index++] = 0;
>>>>> +
>>>>> + for (i = 0; i < count; i++) {
>>>>> + opp = dev_pm_opp_find_bw_ceil(dev, &bandwidth, 0);
>>>>> + if (IS_ERR(opp))
>>>>> + break;
>>>>> +
>>>>> + dev_pm_opp_put(opp);
>>>>> + bandwidths[index++] = bandwidth++;
>>>>> + }
>>>>> +
>>>>> + return index;
>>>>> +}
>>>>> +
>>>>> static int a6xx_gmu_pwrlevels_probe(struct a6xx_gmu *gmu)
>>>>> {
>>>>> struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu,
>>>>> gmu);
>>>>> @@ -1472,6 +1615,16 @@ static int a6xx_gmu_pwrlevels_probe(struct
>>>>> a6xx_gmu *gmu)
>>>>> gmu->current_perf_index = gmu->nr_gpu_freqs - 1;
>>>>> + /*
>>>>> + * The GMU also handles GPU Interconnect Votes so build a list
>>>>> + * of DDR bandwidths from the GPU OPP table
>>>>> + */
>>>>> + if (adreno_gpu->info->features & ADRENO_FEAT_GMU_BW_VOTE)
>>>>> + gmu->nr_gpu_bws = a6xx_gmu_build_bw_table(&gpu->pdev->dev,
>>>>> + gmu->gpu_bw_table, ARRAY_SIZE(gmu->gpu_bw_table));
>>>>> +
>>>>> + gmu->current_perf_index = gmu->nr_gpu_freqs - 1;
>>>
>>> duplicate line.
>>>
>>>>> +
>>>>> /* Build the list of RPMh votes that we'll send to the GMU */
>>>>> return a6xx_gmu_rpmh_votes_init(gmu);
>>>>> }
>>>>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/
>>>>> drm/msm/adreno/a6xx_gmu.h
>>>>> index
>>>>> b4a79f88ccf45cfe651c86d2a9da39541c5772b3..03603eadc0f9ed866899c95e99f333a511ebc3c1 100644
>>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
>>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
>>>>> @@ -19,6 +19,16 @@ struct a6xx_gmu_bo {
>>>>> u64 iova;
>>>>> };
>>>>> +#define GMU_MAX_BCMS 3
>>>>> +
>>>>> +struct a6xx_bcm {
>>>>> + char *name;
>>>>> + unsigned int buswidth;
>>>>> + bool fixed;
>>>>> + unsigned int perfmode;
>>>>> + unsigned int perfmode_bw;
>>>>> +};
>>>>> +
>>>>> /*
>>>>> * These define the different GMU wake up options - these define
>>>>> how both the
>>>>> * CPU and the GMU bring up the hardware
>>>>> @@ -82,6 +92,10 @@ struct a6xx_gmu {
>>>>> unsigned long gpu_freqs[16];
>>>>> u32 gx_arc_votes[16];
>>>>> + int nr_gpu_bws;
>>>>> + unsigned long gpu_bw_table[16];
>>>>> + u32 gpu_bw_votes[16][GMU_MAX_BCMS];
>>>>> +
>>>>> int nr_gmu_freqs;
>>>>> unsigned long gmu_freqs[4];
>>>>> u32 cx_arc_votes[4];
>>>>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/
>>>>> drm/msm/adreno/a6xx_gpu.h
>>>>> index
>>>>> 4aceffb6aae89c781facc2a6e4a82b20b341b6cb..5b80919e595fa1ba0a3afcca55feb89e60870cb1 100644
>>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
>>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
>>>>> @@ -44,6 +44,7 @@ struct a6xx_info {
>>>>> u32 gmu_chipid;
>>>>> u32 gmu_cgc_mode;
>>>>> u32 prim_fifo_threshold;
>>>>> + const struct a6xx_bcm bcm[GMU_MAX_BCMS];
>>>
>>> This table is duplicated a lot. Lets keep a pointer instead. We can
>>> probably use
>>> this pointer as a flag to check for GMU_IB_VOTE support too.
>>
>> It's partially duplicated, basically only the permode bits and level is
>> different.
>>
>> We can move it out when we support more GPUs with this feature.
>>
>> Neil
>>
>>>
>>> -Akhil
>>>
>>>>> };
>>>>> struct a6xx_gpu {
>>>>>
>>>>> --
>>>>> 2.34.1
>>>>>
>>
>
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