Re: [PATCH v2 04/12] soc: renesas: sysc: Add SoC identification for RZ/V2N SoC

[Geert Uytterhoeven]

Hi Prabhakar,

On Mon, 7 Apr 2025 at 21:16, Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>
> Add SoC identification for the RZ/V2N SoC using the System Controller
> (SYS) block.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/soc/renesas/r9a09g056-sys.c
> @@ -0,0 +1,107 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RZ/V2N System controller (SYS) driver
> + *
> + * Copyright (C) 2025 Renesas Electronics Corp.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/device.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/string.h>
> +
> +#include "rz-sysc.h"
> +
> +/* Register Offsets */
> +#define SYS_LSI_MODE           0x300
> +#define SYS_LSI_MODE_SEC_EN    BIT(16)
> +/*
> + * BOOTPLLCA[1:0]
> + *         [0,0] => 1.1GHZ
> + *         [0,1] => 1.5GHZ
> + *         [1,0] => 1.6GHZ
> + *         [1,1] => 1.7GHZ
> + */
> +#define SYS_LSI_MODE_STAT_BOOTPLLCA55  GENMASK(12, 11)
> +#define SYS_LSI_MODE_CA55_1_7GHZ       0x3
> +
> +#define SYS_LSI_PRR                    0x308
> +#define SYS_LSI_PRR_GPU_DIS            BIT(0)
> +#define SYS_LSI_PRR_ISP_DIS            BIT(4)
> +
> +#define SYS_RZV2N_FEATURE_G31          BIT(0)
> +#define SYS_RZV2N_FEATURE_C55          BIT(1)
> +#define SYS_RZV2N_FEATURE_SEC          BIT(2)
> +
> +static void rzv2n_sys_print_id(struct device *dev,
> +                              void __iomem *sysc_base,
> +                              struct soc_device_attribute *soc_dev_attr)
> +{
> +       unsigned int part_number;
> +       char features[75] = "";
> +       u32 prr_val, mode_val;
> +       u8 feature_flags;
> +
> +       prr_val = readl(sysc_base + SYS_LSI_PRR);
> +       mode_val = readl(sysc_base + SYS_LSI_MODE);
> +
> +       /* Check GPU, ISP and Cryptographic configuration */
> +       feature_flags = !(prr_val & SYS_LSI_PRR_GPU_DIS) ? SYS_RZV2N_FEATURE_G31 : 0;
> +       feature_flags |= !(prr_val & SYS_LSI_PRR_ISP_DIS) ? SYS_RZV2N_FEATURE_C55 : 0;
> +       feature_flags |= (mode_val & SYS_LSI_MODE_SEC_EN) ? SYS_RZV2N_FEATURE_SEC : 0;
> +
> +       part_number = 41;
> +       if (feature_flags & SYS_RZV2N_FEATURE_G31)
> +               part_number++;
> +       if (feature_flags & SYS_RZV2N_FEATURE_C55)
> +               part_number += 2;
> +       if (feature_flags & SYS_RZV2N_FEATURE_SEC)
> +               part_number += 4;

The above construct can be simplified to

    part_number = 41 + feature_flags;

> +       if (feature_flags) {
> +               unsigned int features_len = sizeof(features);
> +
> +               strscpy(features, "with ");
> +               if (feature_flags & SYS_RZV2N_FEATURE_G31)
> +                       strlcat(features, "GE3D (Mali-G31)", features_len);
> +
> +               if (feature_flags == (SYS_RZV2N_FEATURE_G31 |
> +                                     SYS_RZV2N_FEATURE_C55 |
> +                                     SYS_RZV2N_FEATURE_SEC))
> +                       strlcat(features, ", ", features_len);
> +               else if ((feature_flags & SYS_RZV2N_FEATURE_G31) &&
> +                        (feature_flags & (SYS_RZV2N_FEATURE_C55 | SYS_RZV2N_FEATURE_SEC)))
> +                       strlcat(features, " and ", features_len);
> +
> +               if (feature_flags & SYS_RZV2N_FEATURE_SEC)
> +                       strlcat(features, "Cryptographic engine", features_len);
> +
> +               if ((feature_flags & SYS_RZV2N_FEATURE_SEC) &&
> +                   (feature_flags & SYS_RZV2N_FEATURE_C55))
> +                       strlcat(features, " and ", features_len);
> +
> +               if (feature_flags & SYS_RZV2N_FEATURE_C55)
> +                       strlcat(features, "ISP (Mali-C55)", features_len);
> +       }

The above looks overly complicated to me.  What about handling it
like on RZ/V2H?  I agree having 3x "with" doesn't look nice, but you
could just drop all "with"s.

> +       dev_info(dev, "Detected Renesas %s %sn%d Rev %s %s\n", soc_dev_attr->family,
> +                soc_dev_attr->soc_id, part_number, soc_dev_attr->revision, features);

This prints a trailing space if features is empty.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds