RE: [RFC PATCH 2/4] clk: renesas: rzg2l-cpg: Add support to stack the resets instead of indexing

[Biju Das]

> Subject: RE: [RFC PATCH 2/4] clk: renesas: rzg2l-cpg: Add support to stack
> the resets instead of indexing
> 
> Hi Lad Prabhakar,
> 
> Thanks for the patch.
> 
> > Subject: [RFC PATCH 2/4] clk: renesas: rzg2l-cpg: Add support to stack
> > the resets instead of indexing
> >
> > Instead of indexing the resets, stack them and instead create an id
> > member in struct rzg2l_reset to store the index. With this approach
> > for every id we will have to loop through the resets array to match the
> id.
> >
> > This in preparation to add support for Renesas RZ/Five CPG in
> > r9a07g043- cpg.c file where the resets array will be split up into
> > three i.e. common and two SoC specific.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > ---
> >  drivers/clk/renesas/rzg2l-cpg.c | 76
> > ++++++++++++++++++++++++++------- drivers/clk/renesas/rzg2l-cpg.h |  4
> > +-
> >  2 files changed, 63 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/clk/renesas/rzg2l-cpg.c
> > b/drivers/clk/renesas/rzg2l- cpg.c index 1ce35f65682b..94fe307ec4c5
> > 100644
> > --- a/drivers/clk/renesas/rzg2l-cpg.c
> > +++ b/drivers/clk/renesas/rzg2l-cpg.c
> > @@ -681,14 +681,37 @@ rzg2l_cpg_register_mod_clk(const struct
> > rzg2l_mod_clk *mod,
> >
> >  #define rcdev_to_priv(x)	container_of(x, struct rzg2l_cpg_priv,
> > rcdev)
> >
> > +static const struct rzg2l_reset
> > +*rzg2l_get_reset_ptr(struct rzg2l_cpg_priv *priv,
> > +		     unsigned long id)
> > +
> > +{
> > +	const struct rzg2l_cpg_info *info = priv->info;
> > +	unsigned int i;
> > +
> > +	for (i = 0; i < priv->num_resets; i++) {
> > +		if (info->resets[i].id == id)
> > +			return &info->resets[i];
> > +	}
> 
> Is it not possible to use shared reset like RZ/G2L and RZ/V2L?, which has
> optimal memory and performance wise we can avoid bigger loop.
> 
> Like adding Last index of RZ/Five as last reset index and Handle RZ/G2UL
> specific as invalid reset index in xlate??

Or add a invalidate_resets() callback to info structure and in probe, call this
Callback,if present to invalidate the resets which are not specific to this SoC.


> 
> 
> > +
> > +	return NULL;
> > +}
> > +
> >  static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,
> >  			   unsigned long id)
> >  {
> >  	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
> > -	const struct rzg2l_cpg_info *info = priv->info;
> > -	unsigned int reg = info->resets[id].off;
> > -	u32 dis = BIT(info->resets[id].bit);
> > -	u32 we = dis << 16;
> > +	const struct rzg2l_reset *reset;
> > +	unsigned int reg;
> > +	u32 dis, we;
> > +
> > +	reset = rzg2l_get_reset_ptr(priv, id);
> > +	if (!reset)
> > +		return -EINVAL;
> > +
> > +	reg = reset->off;
> > +	dis = BIT(reset->bit);
> > +	we = dis << 16;
> >
> >  	dev_dbg(rcdev->dev, "reset id:%ld offset:0x%x\n", id,
> > CLK_RST_R(reg));
> >
> > @@ -708,9 +731,16 @@ static int rzg2l_cpg_assert(struct
> > reset_controller_dev *rcdev,
> >  			    unsigned long id)
> >  {
> >  	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
> > -	const struct rzg2l_cpg_info *info = priv->info;
> > -	unsigned int reg = info->resets[id].off;
> > -	u32 value = BIT(info->resets[id].bit) << 16;
> > +	const struct rzg2l_reset *reset;
> > +	unsigned int reg;
> > +	u32 value;
> > +
> > +	reset = rzg2l_get_reset_ptr(priv, id);
> > +	if (!reset)
> > +		return -EINVAL;
> > +
> > +	reg = reset->off;
> > +	value = BIT(reset->bit) << 16;
> >
> >  	dev_dbg(rcdev->dev, "assert id:%ld offset:0x%x\n", id,
> > CLK_RST_R(reg));
> >
> > @@ -722,11 +752,17 @@ static int rzg2l_cpg_deassert(struct
> > reset_controller_dev *rcdev,
> >  			      unsigned long id)
> >  {
> >  	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
> > -	const struct rzg2l_cpg_info *info = priv->info;
> > -	unsigned int reg = info->resets[id].off;
> > -	u32 dis = BIT(info->resets[id].bit);
> > -	u32 value = (dis << 16) | dis;
> > +	const struct rzg2l_reset *reset;
> > +	unsigned int reg;
> > +	u32 dis, value;
> > +
> > +	reset = rzg2l_get_reset_ptr(priv, id);
> > +	if (!reset)
> > +		return -EINVAL;
> >
> > +	reg = reset->off;
> > +	dis = BIT(reset->bit);
> > +	value = (dis << 16) | dis;
> >  	dev_dbg(rcdev->dev, "deassert id:%ld offset:0x%x\n", id,
> >  		CLK_RST_R(reg));
> >
> > @@ -738,9 +774,16 @@ static int rzg2l_cpg_status(struct
> > reset_controller_dev *rcdev,
> >  			    unsigned long id)
> >  {
> >  	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
> > -	const struct rzg2l_cpg_info *info = priv->info;
> > -	unsigned int reg = info->resets[id].off;
> > -	u32 bitmask = BIT(info->resets[id].bit);
> > +	const struct rzg2l_reset *reset;
> > +	unsigned int reg;
> > +	u32 bitmask;
> > +
> > +	reset = rzg2l_get_reset_ptr(priv, id);
> > +	if (!reset)
> > +		return -EINVAL;
> > +
> > +	reg = reset->off;
> > +	bitmask = BIT(reset->bit);
> >
> >  	return !(readl(priv->base + CLK_MRST_R(reg)) & bitmask);  } @@ -
> > 756,10 +799,11 @@ static int rzg2l_cpg_reset_xlate(struct
> > reset_controller_dev *rcdev,
> >  				 const struct of_phandle_args *reset_spec)  {
> >  	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
> > -	const struct rzg2l_cpg_info *info = priv->info;
> >  	unsigned int id = reset_spec->args[0];
> > +	const struct rzg2l_reset *reset;
> >
> > -	if (id >= rcdev->nr_resets || !info->resets[id].off) {
> > +	reset = rzg2l_get_reset_ptr(priv, id);
> > +	if (!reset) {
> >  		dev_err(rcdev->dev, "Invalid reset index %u\n", id);
> >  		return -EINVAL;
> >  	}
> > diff --git a/drivers/clk/renesas/rzg2l-cpg.h
> > b/drivers/clk/renesas/rzg2l- cpg.h index 92c88f42ca7f..a99f2ba7868f
> > 100644
> > --- a/drivers/clk/renesas/rzg2l-cpg.h
> > +++ b/drivers/clk/renesas/rzg2l-cpg.h
> > @@ -152,12 +152,14 @@ struct rzg2l_mod_clk {
> >   * @bit: reset bit
> >   */
> >  struct rzg2l_reset {
> > +	unsigned int id;
> 
> Now you are adding 4 bytes to each reset entry in the LUT.
> 
> Cheers,
> Biju
> 
> >  	u16 off;
> >  	u8 bit;
> >  };
> 
> >
> >  #define DEF_RST(_id, _off, _bit)	\
> > -	[_id] = { \
> > +	{ \
> > +		.id = (_id), \
> >  		.off = (_off), \
> >  		.bit = (_bit) \
> >  	}
> > --
> > 2.25.1