Re: [PATCH v9 4/9] soc: mediatek: Add multiple step bus protection control

From: Nicolas Boichat
Date: Mon Dec 16 2019 - 02:22:15 EST

On Tue, Dec 10, 2019 at 2:47 PM Weiyi Lu <weiyi.lu@xxxxxxxxxxxx> wrote:
>
> Both MT8183 & MT6765 have more control steps of bus protection
> than previous project. And there add more bus protection registers
> reside at infracfg & smi-common. Also add new APIs for multiple
> step bus protection control with more customized arguments.
>
> Signed-off-by: Weiyi Lu <weiyi.lu@xxxxxxxxxxxx>
> ---
> drivers/soc/mediatek/Makefile | 2 +-
> drivers/soc/mediatek/mtk-scpsys-ext.c | 99 +++++++++++++++++++++++++++++++++
> drivers/soc/mediatek/mtk-scpsys.c | 39 +++++++++----
> include/linux/soc/mediatek/scpsys-ext.h | 39 +++++++++++++
> 4 files changed, 168 insertions(+), 11 deletions(-)
> create mode 100644 drivers/soc/mediatek/mtk-scpsys-ext.c
> create mode 100644 include/linux/soc/mediatek/scpsys-ext.h
>
> diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
> index b017330..b442be9 100644
> --- a/drivers/soc/mediatek/Makefile
> +++ b/drivers/soc/mediatek/Makefile
> @@ -1,5 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
> -obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
> +obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o mtk-scpsys-ext.o
> obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
> obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
> diff --git a/drivers/soc/mediatek/mtk-scpsys-ext.c b/drivers/soc/mediatek/mtk-scpsys-ext.c
> new file mode 100644
> index 0000000..4f1adda
> --- /dev/null
> +++ b/drivers/soc/mediatek/mtk-scpsys-ext.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + * Author: Owen Chen <Owen.Chen@xxxxxxxxxxxx>
> + */
> +#include <linux/ktime.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_device.h>
> +#include <linux/regmap.h>
> +#include <linux/soc/mediatek/scpsys-ext.h>
> +
> +#define MTK_POLL_DELAY_US 10
> +#define MTK_POLL_TIMEOUT USEC_PER_SEC
> +
> +static int set_bus_protection(struct regmap *map, u32 mask, u32 ack_mask,
> + u32 reg_set, u32 reg_sta, u32 reg_en)
> +{
> + u32 val;
> +
> + if (reg_set)
> + regmap_write(map, reg_set, mask);
> + else
> + regmap_update_bits(map, reg_en, mask, mask);

At least for 8183, we never seen to use the reg_set case, can we
simplify this function?

> +
> + return regmap_read_poll_timeout(map, reg_sta,
> + val, (val & ack_mask) == ack_mask,
> + MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);

>From 8183, I see that you have either:
1. mask == ack_mask
2. ack_mask == 0 (essentially this skips this test)

Would it be simpler to just skip this test if reg_sta == 0, and always
assume mask == ack_mask otherwise?

e.g.
if (reg_sta == 0)
return 0;

return regmap_read_poll_timeout(map, reg_sta,
val, (val & mask) == mask,
MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);

> +}
> +
> [snip]
> +
> +int mtk_scpsys_ext_set_bus_protection(const struct bus_prot *bp_table,
> + struct regmap *infracfg, struct regmap *smi_common)
> +{
> + int i;
> +
> + for (i = 0; i < MAX_STEPS; i++) {
> + struct regmap *map = NULL;
> + int ret;
> +
> + if (bp_table[i].type == INVALID_TYPE)
> + continue;

break? (but yes the one below in mtk_scpsys_ext_clear_bus_protection
has to be continue).

> + else if (bp_table[i].type == IFR_TYPE)
> + map = infracfg;
> + else if (bp_table[i].type == SMI_TYPE)
> + map = smi_common;
> +
> + ret = set_bus_protection(map,
> + bp_table[i].mask, bp_table[i].mask,
> + bp_table[i].set_ofs, bp_table[i].sta_ofs,
> + bp_table[i].en_ofs);
> +
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +int mtk_scpsys_ext_clear_bus_protection(const struct bus_prot *bp_table,
> + struct regmap *infracfg, struct regmap *smi_common)
> +{
> + int i;
> +
> + for (i = MAX_STEPS - 1; i >= 0; i--) {
> + struct regmap *map = NULL;
> + int ret;
> +
> + if (bp_table[i].type == INVALID_TYPE)
> + continue;
> + else if (bp_table[i].type == IFR_TYPE)
> + map = infracfg;
> + else if (bp_table[i].type == SMI_TYPE)
> + map = smi_common;
> +
> + ret = clear_bus_protection(map,
> + bp_table[i].mask, bp_table[i].clr_ack_mask,
> + bp_table[i].clr_ofs, bp_table[i].sta_ofs,
> + bp_table[i].en_ofs);
> +
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
> index 915d635..466bb749 100644
> --- a/drivers/soc/mediatek/mtk-scpsys.c
> +++ b/drivers/soc/mediatek/mtk-scpsys.c
> @@ -12,6 +12,7 @@
> #include <linux/pm_domain.h>
> #include <linux/regulator/consumer.h>
> #include <linux/soc/mediatek/infracfg.h>
> +#include <linux/soc/mediatek/scpsys-ext.h>
>
> #include <dt-bindings/power/mt2701-power.h>
> #include <dt-bindings/power/mt2712-power.h>
> @@ -120,6 +121,7 @@ enum clk_id {
> * @basic_clk_id: provide the same purpose with field "clk_id"
> * by declaring basic clock prefix name rather than clk_id.
> * @caps: The flag for active wake-up action.
> + * @bp_table: The mask table for multiple step bus protection.
> */
> struct scp_domain_data {
> const char *name;
> @@ -131,6 +133,7 @@ struct scp_domain_data {
> enum clk_id clk_id[MAX_CLKS];
> const char *basic_clk_id[MAX_CLKS];
> u8 caps;
> + struct bus_prot bp_table[MAX_STEPS];

As with the previous patch, I'm not a big fan of having 2 approaches
for something similar (bus_prot_mask vs bp_table), can we define a
simple macro for this?
e.g.:
.bp_table = BUS_PROT_SINGLE(mask)