by Weiyi Lu

[permalink] [raw]

Subject: Re: [PATCH v5 10/14] soc: mediatek: Add multiple step bus protection control

On Thu, 2019-03-21 at 13:57 +0800, Nicolas Boichat wrote:
> On Tue, Mar 19, 2019 at 4:02 PM Weiyi Lu <[email protected]> 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 customize arguments.
> >
> > Signed-off-by: Weiyi Lu <[email protected]>
> > ---
> > drivers/soc/mediatek/Makefile | 2 +-
> > drivers/soc/mediatek/mtk-scpsys-ext.c | 99 +++++++++++++++++++++++++
> > drivers/soc/mediatek/mtk-scpsys.c | 24 ++++++
> > include/linux/soc/mediatek/scpsys-ext.h | 39 ++++++++++
> > 4 files changed, 163 insertions(+), 1 deletion(-)
> > 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 64ce5eeaba32..b9dbad6b12f9 100644
> > --- a/drivers/soc/mediatek/Makefile
> > +++ b/drivers/soc/mediatek/Makefile
> > @@ -1,4 +1,4 @@
> > 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 000000000000..f630edb2f65d
> > --- /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 <[email protected]>
> > + */
> > +#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);
> > +
> > + return regmap_read_poll_timeout(map, reg_sta,
> > + val, (val & ack_mask) == ack_mask,
> > + MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
> > +}
> > +
> > +static int clear_bus_protection(struct regmap *map, u32 mask, u32 ack_mask,
> > + u32 reg_clr, u32 reg_sta, u32 reg_en)
> > +{
> > + u32 val;
> > +
> > + if (reg_clr)
> > + regmap_write(map, reg_clr, mask);
> > + else
> > + regmap_update_bits(map, reg_en, mask, 0);
> > +
> > + return regmap_read_poll_timeout(map, reg_sta,
> > + val, !(val & ack_mask),
> > + MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
> > +}
> > +
> > +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 && bp_table[i].mask; i++) {
> > + struct regmap *map;
> > + int ret;
> > +
> > + if (bp_table[i].type == IFR_TYPE)
> > + map = infracfg;
> > + else if (bp_table[i].type == SMI_TYPE)
> > + map = smi_common;
> > + else
> > + return -EINVAL;
> > +
> > + 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;
>
> Should you undo the rest of the operations and clear bus protection on
> the ones that were already enabled?
>

Actually we assume all bus protection operations need to be done
successfully, undo might not be a very useful error handling here. But
I'll consider it carefully.

> > + }
> > +
> > + 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--) {
>
> So when you set protection, you stop at the first bp_table[i].mask ==
> 0, but when you clear it, you call clear_bus_protection for those, as
> well. You should just skip over the ones when bp_table[i].mask == 0?
>
> e.g.
> if (!bp_table[i].mask)
> continue;
>

I'll use the idea of INVALID_TYPE = 0 to fix.

> > + struct regmap *map;
> > + int ret;
> > +
> > + if (bp_table[i].type == IFR_TYPE)
> > + map = infracfg;
> > + else if (bp_table[i].type == SMI_TYPE)
> > + map = smi_common;
> > + else
> > + return -EINVAL;
> > +
> > + 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;
>
> Similar question, is it ok to just abort? Or should you try to clear
> the protection on all others, too?
>
> > + }
> > +
> > + return 0;
> > +}
> > diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
> > index c6360de4e41e..181bf7bce591 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>
> > @@ -121,6 +122,7 @@ static const char * const clk_names[] = {
> > * @basic_clk_name: 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;
> > @@ -132,6 +134,7 @@ struct scp_domain_data {
> > enum clk_id clk_id[MAX_CLKS];
> > const char *basic_clk_name[MAX_CLKS];
> > u8 caps;
> > + struct bus_prot bp_table[MAX_STEPS];
> > };
> >
> > struct scp;
> > @@ -155,6 +158,7 @@ struct scp {
> > struct device *dev;
> > void __iomem *base;
> > struct regmap *infracfg;
> > + struct regmap *smi_common;
> > struct scp_ctrl_reg ctrl_reg;
> > bool bus_prot_reg_update;
> > };
> > @@ -291,6 +295,10 @@ static int scpsys_bus_protect_enable(struct scp_domain *scpd)
> > ret = mtk_infracfg_set_bus_protection(scp->infracfg,
> > scpd->data->bus_prot_mask,
> > scp->bus_prot_reg_update);
> > + } else if (scpd->data->bp_table[0].mask) {
> > + ret = mtk_scpsys_ext_set_bus_protection(scpd->data->bp_table,
> > + scp->infracfg,
> > + scp->smi_common);
> > }
> >
> > return ret;
> > @@ -305,6 +313,11 @@ static int scpsys_bus_protect_disable(struct scp_domain *scpd)
> > ret = mtk_infracfg_clear_bus_protection(scp->infracfg,
> > scpd->data->bus_prot_mask,
> > scp->bus_prot_reg_update);
> > + } else if (scpd->data->bp_table[0].mask) {
> > + ret = mtk_scpsys_ext_clear_bus_protection(
> > + scpd->data->bp_table,
> > + scp->infracfg,
> > + scp->smi_common);
> > }
> >
> > return ret;
> > @@ -475,6 +488,17 @@ static struct scp *init_scp(struct platform_device *pdev,
> > return ERR_CAST(scp->infracfg);
> > }
> >
> > + scp->smi_common = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
> > + "smi_comm");
> > +
> > + if (scp->smi_common == ERR_PTR(-ENODEV)) {
> > + scp->smi_common = NULL;
> > + } else if (IS_ERR(scp->smi_common)) {
> > + dev_err(&pdev->dev, "Cannot find smi_common controller: %ld\n",
> > + PTR_ERR(scp->smi_common));
> > + return ERR_CAST(scp->smi_common);
> > + }
> > +
> > for (i = 0; i < num; i++) {
> > struct scp_domain *scpd = &scp->domains[i];
> > const struct scp_domain_data *data = &scp_domain_data[i];
> > diff --git a/include/linux/soc/mediatek/scpsys-ext.h b/include/linux/soc/mediatek/scpsys-ext.h
> > new file mode 100644
> > index 000000000000..d0ed295c88a7
> > --- /dev/null
> > +++ b/include/linux/soc/mediatek/scpsys-ext.h
> > @@ -0,0 +1,39 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef __SOC_MEDIATEK_SCPSYS_EXT_H
> > +#define __SOC_MEDIATEK_SCPSYS_EXT_H
> > +
> > +#define MAX_STEPS 4
> > +
> > +#define BUS_PROT(_type, _set_ofs, _clr_ofs, \
> > + _en_ofs, _sta_ofs, _mask, _clr_ack_mask) { \
> > + .type = _type, \
> > + .set_ofs = _set_ofs, \
> > + .clr_ofs = _clr_ofs, \
> > + .en_ofs = _en_ofs, \
> > + .sta_ofs = _sta_ofs, \
> > + .mask = _mask, \
> > + .clr_ack_mask = _clr_ack_mask, \
> > + }
> > +
> > +enum regmap_type {
>
> Maybe add INVALID_TYPE = 0, so that you can skip over those when
> looping over them, instead of checking if mask is 0?
>

Thanks for advise. I'll use it in next version.

> > + IFR_TYPE,
> > + SMI_TYPE,
> > + MAX_REGMAP_TYPE,
>
> This is not used, right? Do you really need it?
>

I'll remove it.

> > +};
> > +
> > +struct bus_prot {
> > + enum regmap_type type;
> > + u32 set_ofs;
> > + u32 clr_ofs;
> > + u32 en_ofs;
> > + u32 sta_ofs;
> > + u32 mask;
> > + u32 clr_ack_mask;
> > +};
> > +
> > +int mtk_scpsys_ext_set_bus_protection(const struct bus_prot *bp_table,
> > + struct regmap *infracfg, struct regmap *smi_common);
> > +int mtk_scpsys_ext_clear_bus_protection(const struct bus_prot *bp_table,
> > + struct regmap *infracfg, struct regmap *smi_common);
> > +
> > +#endif /* __SOC_MEDIATEK_SCPSYS_EXT_H */
> > --
> > 2.18.0
> >