Re: [PATCH 1/2] scsi: ufs: Add Multi-Circular Queue support

Asutosh Das (asd)
2022-07-22T17:35:16Z

Hi Avri
Thanks for taking a look.

On 7/22/2022 12:31 AM, Avri Altman wrote:
>> +static int ufshcd_mcq_config_resource(struct ufs_hba *hba)
>> +{
>> + struct platform_device *pdev = to_platform_device(hba->dev);
>> + struct ufshcd_res_info_t *res;
>> + struct resource *res_mem, *res_mcq;
>> + int i, ret = 0;
>> +
>> + memcpy(hba->res, ufshcd_res_info, sizeof(ufshcd_res_info));
>> +
>> + for (i = 0; i < RES_MAX; i++) {
>> + res = &hba->res[i];
>> +
>> + res->resource = platform_get_resource_byname(pdev,
>> + IORESOURCE_MEM,
>> + res->name);
>> + if (!res->resource) {
>> + dev_info(hba->dev, "Resource %s not provided\n", res-
>>> name);
>> + if (i == RES_MEM)
>> + return -ENOMEM;
>> + continue;
>> + } else if (i == RES_MEM) {
>> + res_mem = res->resource;
>> + res->base = hba->mmio_base;
>> + continue;
>> + }
>> +
>> + res->base = devm_ioremap_resource(hba->dev, res->resource);
>> + if (IS_ERR(res->base)) {
>> + dev_err(hba->dev, "Failed to map res %s, err = %d\n",
>> + res->name, (int)PTR_ERR(res->base));
>> + res->base = NULL;
>> + ret = PTR_ERR(res->base);
>> + goto out_err;
>> + }
>> + }
>> +
>> + res = &hba->res[RES_MCQ];
>> + /* MCQ resource provided */
>> + if (res->base)
>> + goto out;
>> +
>> + /* Manually allocate MCQ resource */
> Did you consider to force providing the MCQ configuration?
>
>> + res_mcq = res->resource;
>> + res_mcq = devm_kzalloc(hba->dev, sizeof(*res_mcq), GFP_KERNEL);
>> + if (!res_mcq) {
>> + dev_err(hba->dev, "Failed to alloate MCQ resource\n");
>> + goto out_err;
>> + }
>> + res->is_alloc = true;
>> +
>> + res_mcq->start = res_mem->start +
>> + mcq_sqattr_offset(hba->mcq_capabilities);
>> + res_mcq->end = res_mcq->start + 32 * MCQ_QCFG_SIZE - 1;
> Shouldn't there can be MCQCap.MAXQ queues and no more than 32?
>
Yes correct. Will change it in the next version.
>
>> +int ufshcd_mcq_init(struct ufs_hba *hba)
>> +{
>> + struct Scsi_Host *host = hba->host;
>> + struct ufs_hw_queue *hwq;
>> + int i, ret = 0;
>> +
>> + if (!is_mcq_supported(hba))
>> + return 0;
>> +
>> + ret = ufshcd_mcq_config_resource(hba);
>> + if (ret) {
>> + dev_err(hba->dev, "Failed to config MCQ resource\n");
>> + return ret;
>> + }
>> +
>> + ret = ufshcd_vops_config_mcq_rop(hba);
>> + if (ret) {
>> + dev_err(hba->dev, "MCQ Runtime Operation Pointers not
>> configured\n");
>> + goto out_err;
>> + }
>> +
>> + hba->nr_queues[HCTX_TYPE_DEFAULT] = num_possible_cpus();
>> + hba->nr_queues[HCTX_TYPE_READ] = 0;
>> + hba->nr_queues[HCTX_TYPE_POLL] = 1;
>> +
>> + for (i = 0; i < HCTX_MAX_TYPES; i++)
>> + host->nr_hw_queues += hba->nr_queues[i];
>> +
>> + host->can_queue = hba->nutrs;
>> + host->cmd_per_lun = hba->nutrs;
>> +
>> + /* One more reserved for dev_cmd_queue */
>> + hba->nr_hw_queues = host->nr_hw_queues + 1;
> Is it possible, since MCQ memory space is *added* to the UTR & UTMR lists,
> That we'll keep using the legacy doorbell for query commands?
> Wouldn't it will simplify the hw_queue bookkeeping
>
Umm, I didn't understand this suggestion. Please can you elaborate a bit.
When MCQ mode is selected the Config.QT is set to 1.
So how would we keep using the legacy doorbell for query commands?

>
>> -#define ufshcd_hex_dump(prefix_str, buf, len) do { \
>> - size_t __len = (len); \
>> - print_hex_dump(KERN_ERR, prefix_str, \
>> - __len > 4 ? DUMP_PREFIX_OFFSET : DUMP_PREFIX_NONE,\
>> - 16, 4, buf, __len, false); \
>> +#define ufshcd_hex_dump(prefix_str, buf, len) do { \
>> + size_t __len = (len); \
>> + \
>> + print_hex_dump(KERN_ERR, prefix_str, \
>> + __len > 4 ? DUMP_PREFIX_OFFSET : DUMP_PREFIX_NONE, \
>> + 16, 4, buf, __len, false); \
>> + \
>> } while (0)
> Should this be part of this patch?
>
No it shouldn't. Will remove this.
>> +#define UFSHCD_MCQ_IO_QUEUE_OFFSET 1
> Maybe add a comment above: "queue 0 is reserved for query commands" or something
> That is if the query commands don't use the legacy doorbell
>
>> +static inline bool ufshcd_is_hwq_full(struct ufs_hw_queue *q)
>> +{
>> + return (q->sq_hp_slot == ((q->sq_tp_slot + 1) %
>> + q->max_entries));
>> +}
> Isn't sq_tp_slot is already % q->max_entries ?
>
This function is unused in this patchset and I will remove it in the
next version.

>
> Thanks,
> Avri