Re: [PATCH v4 3/7] drm/msm: adreno: dynamically generate GMU bw table

[Neil Armstrong <neil.armstrong@linaro.org>]

On 09/12/2024 13:11, Akhil P Oommen wrote:
> On 12/5/2024 8:31 PM, Neil Armstrong wrote:
>> The Adreno GPU Management Unit (GMU) can also scale the ddr
>> bandwidth along the frequency and power domain level, but for
>> now we statically fill the bw_table with values from the
>> downstream driver.
>>
>> Only the first entry is used, which is a disable vote, so we
>> currently rely on scaling via the linux interconnect paths.
>>
>> Let's dynamically generate the bw_table with the vote values
>> previously calculated from the OPPs.
>>
>> Those entries will then be used by the GMU when passing the
>> appropriate bandwidth level while voting for a gpu frequency.
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
>> ---
>>   drivers/gpu/drm/msm/adreno/a6xx_hfi.c | 41 ++++++++++++++++++++++++++++++++++-
>>   1 file changed, 40 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_hfi.c b/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
>> index cb8844ed46b29c4569d05eb7a24f7b27e173190f..fc4bfad51de9a3b6617fbbd03471a5851d43ce88 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
>> @@ -5,7 +5,10 @@
>>   #include <linux/circ_buf.h>
>>   #include <linux/list.h>
>>   
>> +#include <dt-bindings/interconnect/qcom,icc.h>
>> +
>>   #include <soc/qcom/cmd-db.h>
>> +#include <soc/qcom/tcs.h>
>>   
>>   #include "a6xx_gmu.h"
>>   #include "a6xx_gmu.xml.h"
>> @@ -259,6 +262,39 @@ static int a6xx_hfi_send_perf_table(struct a6xx_gmu *gmu)
>>   		NULL, 0);
>>   }
>>   
>> +static void a6xx_generate_bw_table(const struct a6xx_info *info, struct a6xx_gmu *gmu,
>> +				   struct a6xx_hfi_msg_bw_table *msg)
>> +{
>> +	unsigned int i, j;
>> +
>> +	msg->ddr_wait_bitmask = QCOM_ICC_TAG_ALWAYS;
> 
> Why this is QCOM_ICC_TAG_ALWAYS?
> 
> IIRC, this bitmask informs RPMH whether it should wait for previous BCM
> vote to complete. Can we implement the same logic from kgsl to create
> this bitmask?

Ack, Let me check

> 
> 
>> +
>> +	for (i = 0; i < GMU_MAX_BCMS; i++) {
>> +		if (!info->bcms[i].name)
>> +			break;
>> +		msg->ddr_cmds_addrs[i] = cmd_db_read_addr(info->bcms[i].name);
>> +	}
>> +	msg->ddr_cmds_num = i;
>> +
>> +	for (i = 0; i < gmu->nr_gpu_bws; ++i)
>> +		for (j = 0; j < msg->ddr_cmds_num; j++)
>> +			msg->ddr_cmds_data[i][j] = gmu->gpu_ib_votes[i][j];
>> +	msg->bw_level_num = gmu->nr_gpu_bws;
>> +
>> +	/*
>> +	 * These are the CX (CNOC) votes - these are used by the GMU
>> +	 * The 'CN0' BCM is used on all targets, and votes are basically
>> +	 * 'off' and 'on' states with first bit to enable the path.
>> +	 */
>> +
>> +	msg->cnoc_cmds_num = 1;
>> +	msg->cnoc_wait_bitmask = QCOM_ICC_TAG_AMC;
> 
> Same here.
> 
> Rest looks fine to me.

Thanks,
Neil

> 
> -Akhil
> 
>> +
>> +	msg->cnoc_cmds_addrs[0] = cmd_db_read_addr("CN0");
>> +	msg->cnoc_cmds_data[0][0] = BCM_TCS_CMD(true, false, 0, 0);
>> +	msg->cnoc_cmds_data[1][0] = BCM_TCS_CMD(true, true, 0, BIT(0));
>> +}
>> +
>>   static void a618_build_bw_table(struct a6xx_hfi_msg_bw_table *msg)
>>   {
>>   	/* Send a single "off" entry since the 618 GMU doesn't do bus scaling */
>> @@ -664,6 +700,7 @@ static int a6xx_hfi_send_bw_table(struct a6xx_gmu *gmu)
>>   	struct a6xx_hfi_msg_bw_table *msg;
>>   	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;
>>   
>>   	if (gmu->bw_table)
>>   		goto send;
>> @@ -672,7 +709,9 @@ static int a6xx_hfi_send_bw_table(struct a6xx_gmu *gmu)
>>   	if (!msg)
>>   		return -ENOMEM;
>>   
>> -	if (adreno_is_a618(adreno_gpu))
>> +	if (info->bcms && gmu->nr_gpu_bws > 1)
>> +		a6xx_generate_bw_table(info, gmu, msg);
>> +	else if (adreno_is_a618(adreno_gpu))
>>   		a618_build_bw_table(msg);
>>   	else if (adreno_is_a619(adreno_gpu))
>>   		a619_build_bw_table(msg);
>>
>