Re: [PATCH v7 2/2] drivers: soc: Add LLCC driver

[Andy Shevchenko]

On Wed, May 16, 2018 at 8:43 PM, Rishabh Bhatnagar
<rishabhb@xxxxxxxxxxxxxx> wrote:
> LLCC (Last Level Cache Controller) provides additional cache memory
> in the system. LLCC is partitioned into multiple slices and each
> slice gets its own priority, size, ID and other config parameters.
> LLCC driver programs these parameters for each slice. Clients that
> are assigned to use LLCC need to get information such size & ID of the
> slice they get and activate or deactivate the slice as needed. LLCC driver
> provides API for the clients to perform these operations.

> +static const struct of_device_id sdm845_qcom_llcc_of_match[] = {
> +       { .compatible = "qcom,sdm845-llcc", },

> +       { },

Slightly better w/o comma

> +};

> +static struct platform_driver sdm845_qcom_llcc_driver = {
> +       .driver = {
> +               .name = "sdm845-llcc",

> +               .owner = THIS_MODULE,

No need. See below.

> +               .of_match_table = sdm845_qcom_llcc_of_match,
> +       },
> +       .probe = sdm845_qcom_llcc_probe,
> +};

> +
> +static int __init sdm845_init_qcom_llcc_init(void)
> +{
> +       return platform_driver_register(&sdm845_qcom_llcc_driver);
> +}
> +module_init(sdm845_init_qcom_llcc_init);
> +
> +static void __exit sdm845_exit_qcom_llcc_exit(void)
> +{
> +       platform_driver_unregister(&sdm845_qcom_llcc_driver);
> +}
> +module_exit(sdm845_exit_qcom_llcc_exit);

Why not to use module_platform_driver() macro?

> +#define ACTIVATE                      0x1
> +#define DEACTIVATE                    0x2
> +#define ACT_CTRL_OPCODE_ACTIVATE      0x1
> +#define ACT_CTRL_OPCODE_DEACTIVATE    0x2
> +#define ACT_CTRL_ACT_TRIG             0x1

Are these bits? Perhaps BIT() ?

> +#define ACT_CTRL_OPCODE_SHIFT         0x1
> +#define ATTR1_PROBE_TARGET_WAYS_SHIFT 0x2
> +#define ATTR1_FIXED_SIZE_SHIFT        0x3
> +#define ATTR1_PRIORITY_SHIFT          0x4
> +#define ATTR1_MAX_CAP_SHIFT           0x10

Better to use fixed size pattern, i.e. 0x01, 0x02, 0x03, 0x04, 0x10.

> +#define ATTR0_RES_WAYS_MASK           0x00000fff
> +#define ATTR0_BONUS_WAYS_MASK         0x0fff0000

GENMASK()

> +#define LLCC_LB_CNT_MASK               0xf0000000

Ditto.

> +#define MAX_CAP_TO_BYTES(n) (n * 1024)

(n * SZ_1K) ?

> +#define LLCC_TRP_ACT_CTRLn(n) (n * 0x1000)

SZ_4K ?

> +#define LLCC_TRP_STATUSn(n)   (4 + n * 0x1000)

Ditto.

> +struct llcc_slice_desc *llcc_slice_getd(u32 uid)
> +{
> +       const struct llcc_slice_config *cfg;
> +       struct llcc_slice_desc *desc;
> +       u32 sz, count = 0;
> +
> +       cfg = drv_data->cfg;
> +       sz = drv_data->cfg_size;
> +

> +       while (cfg && count < sz) {
> +               if (cfg->usecase_id == uid)
> +                       break;
> +               cfg++;
> +               count++;
> +       }
> +       if (cfg == NULL || count == sz)
> +               return ERR_PTR(-ENODEV);

if (!cfg)
          return ERR_PTR(-ENODEV);

while (cfg->... != uid) {
  cfg++;
  count++;
}

if (count == sz)
 return ...

Though I would rather put it to for () loop.

> +static int llcc_update_act_ctrl(u32 sid,
> +                               u32 act_ctrl_reg_val, u32 status)
> +{
> +       u32 act_ctrl_reg;
> +       u32 status_reg;
> +       u32 slice_status;

> +       int ret = 0;

Useless assignment. Check entire patch series for a such.

> +       ret = regmap_read_poll_timeout(drv_data->regmap, status_reg,
> +       slice_status, !(slice_status & status), 0, LLCC_STATUS_READ_DELAY);

Wrong indentation.

> +       return ret;
> +}

> +       ret = llcc_update_act_ctrl(desc->slice_id, act_ctrl_val,
> +                                 DEACTIVATE);

Perhaps one line (~83 characters here is OK) ?

> +       ret = llcc_update_act_ctrl(desc->slice_id, act_ctrl_val,
> +                                 ACTIVATE);

Ditto.

> +               attr1_cfg = bcast_off +
> +                               LLCC_TRP_ATTR1_CFGn(llcc_table[i].slice_id);
> +               attr0_cfg = bcast_off +
> +                               LLCC_TRP_ATTR0_CFGn(llcc_table[i].slice_id);

Ditto.

> +               attr1_val |= llcc_table[i].probe_target_ways <<
> +                               ATTR1_PROBE_TARGET_WAYS_SHIFT;
> +               attr1_val |= llcc_table[i].fixed_size <<
> +                               ATTR1_FIXED_SIZE_SHIFT;
> +               attr1_val |= llcc_table[i].priority << ATTR1_PRIORITY_SHIFT;

foo |=
  bar << SHIFT;

would look slightly better.

> +int qcom_llcc_probe(struct platform_device *pdev,
> +                     const struct llcc_slice_config *llcc_cfg, u32 sz)
> +{

> +       drv_data->offsets = devm_kzalloc(dev, num_banks * sizeof(u32),
> +                                                       GFP_KERNEL);
> +       if (!drv_data->offsets)
> +               return -ENOMEM;

devm_kcalloc() ?

> +
> +       for (i = 0; i < num_banks; i++)
> +               drv_data->offsets[i] = (i * BANK_OFFSET_STRIDE);

Pointless parens.

> +       drv_data->bitmap = devm_kcalloc(dev,
> +       BITS_TO_LONGS(drv_data->max_slices), sizeof(unsigned long),
> +                                               GFP_KERNEL);
> +       if (!drv_data->bitmap)
> +               return -ENOMEM;

Perhaps at some point someone will add
bitmap_alloc()
devm_bitmap_alloc()

> +       bitmap_zero(drv_data->bitmap, drv_data->max_slices);

Pointless

-- 
With Best Regards,
Andy Shevchenko