Hi Geert, On Mon, Jul 29, 2024 at 9:14 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > > Hi Prabhakar, > > On Sat, Jul 27, 2024 at 12:51 PM Lad, Prabhakar > <prabhakar.csengg@xxxxxxxxx> wrote: > > On Fri, Jul 26, 2024 at 3:53 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > > > On Mon, Jul 15, 2024 at 2:56 PM Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote: > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > > > > > > > Add family-specific clock driver for RZ/V2H(P) SoCs. > > > > > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > > > --- /dev/null > > > > +++ b/drivers/clk/renesas/rzv2h-cpg.h > > > > > > > +#define DEF_RST_BASE(_id, _resindex, _resbit, _monindex, _monbit) \ > > > > + [_id] = { \ > > > > > > Indexing by _id means the reset array will be very sparse. E.g. the > > > innocent-looking r9a09g057_resets[] with only a single entry takes > > > 600 bytes: > > > > > > $ nm -S drivers/clk/renesas/r9a09g057-cpg.o | grep r9a09g057_resets > > > 0000000000000038 0000000000000258 r r9a09g057_resets > > > > > Agreed. > > > > > So please pack the array here, and either unpack it while making the > > > priv->resets copy, or implement translation ("look-up") from ID to > > > packed index in rzv2h_cpg_reset_xlate(). > > > > > OK, I will implement the below: > > > > #define PACK_RESET(_resindex, _resbit, _monindex, _monbit) \ > > (((_resindex) << 24) | ((_resbit) << 16) | ((_monindex) << 8) | (_monbit)) > > > > #define DEF_RST(_resindex, _resbit, _monindex, _monbit) \ > > PACK_RESET(_resindex, _resbit, _monindex, _monbit) > > > > #define GET_RESET_INDEX(x) (((x) >> 24) & 0xFF) > > #define GET_RESET_BIT(x) (((x) >> 16) & 0xFF) > > #define GET_MON_INDEX(x) (((x) >> 8) & 0xFF) > > #define GET_MON_BIT(x) ((x) & 0xFF) > > > > static int rzv2h_cpg_reset_xlate(struct reset_controller_dev *rcdev, > > const struct of_phandle_args *reset_spec) > > { > > struct rzv2h_cpg_priv *priv = rcdev_to_priv(rcdev); > > unsigned int id = reset_spec->args[0]; > > u8 rst_index = id / 16; > > u8 rst_bit = id % 16; > > unsigned int i; > > > > for (i = 0; i < rcdev->nr_resets; i++) { > > u8 cur_index = GET_RESET_INDEX(priv->resets[i]); > > u8 cur_bit = GET_RESET_BIT(priv->resets[i]); > > > > if (rst_index == cur_index && rst_bit == cur_bit) > > return i; > > } > > > > return -EINVAL; > > } > > > > Let me know if this is OK, or to avoid looping in xlate maybe we can > > have a packed entry in the resets property of DT by this way we can > > avoid having the resets array all together? > > Sorry for being unclear. I did not mean packing the fields in the struct > into a single word, but packing the entries in the r9a09g057_resets[] > array. Using the rzv2h_reset structure is fine. > > With: > > #define DEF_RST_BASE(_id, _resindex, _resbit, _monindex, _monbit) \ > [_id] = { \ > .reset_index = (_resindex), \ > .reset_bit = (_resbit), \ > .mon_index = (_monindex), \ > .mon_bit = (_monbit), \ > } > > #define DEF_RST(_resindex, _resbit, _monindex, _monbit) \ > DEF_RST_BASE(RST_ID((_resindex), (_resbit)), _resindex, > _resbit, _monindex, _monbit) > > static const struct rzv2h_reset r9a09g057_resets[] __initconst = { > DEF_RST(9, 5, 4, 6), /* SCIF_0_RST_SYSTEM_N */ > }; > > is expanded into an array of 150 entries (9 * 16 + 5 = 149 empty entries > followed by the SCIF_0_RST_SYSTEM_N entry), which is wasteful. > Over time the array will be filled more, but I expect there will still > be lots of unused entries. > > Hence I suggest to drop the "[id]": > > - define DEF_RST_BASE(_id, _resindex, _resbit, _monindex, _monbit) \ > - [_id] = { \ > +#define DEF_RST(_resindex, _resbit, _monindex, _monbit) \ > + { \ > .reset_index = (_resindex), \ > .reset_bit = (_resbit), \ > .mon_index = (_monindex), \ > .mon_bit = (_monbit), \ > } > - > -#define DEF_RST(_resindex, _resbit, _monindex, _monbit) \ > - DEF_RST_BASE(RST_ID((_resindex), (_resbit)), _resindex, > _resbit, _monindex, _monbit) > > Then r9a09g057_resets[] will contain only non-empty entries, at the > expense of no longer being able to index it directly by reset ID. > To solve the indexing, there are two options. > > Option A: Translate from reset ID to real index during lookup, like > you do in the rzv2h_cpg_reset_xlate() above: > > static int rzv2h_cpg_reset_xlate(struct reset_controller_dev *rcdev, > const struct of_phandle_args *reset_spec) > { > struct rzv2h_cpg_priv *priv = rcdev_to_priv(rcdev); > unsigned int id = reset_spec->args[0]; > u8 rst_index = id / 16; > u8 rst_bit = id % 16; > unsigned int i; > > for (i = 0; i < rcdev->nr_resets; i++) { > if (rst_index == priv->resets[i].reset_index && > rst_bit == ->resets[i].reset_bit) > return i; > } > > return -EINVAL; > } > > Option B: "Unpack" rzv2h_cpg_info.resets[] during copying in > rzv2h_cpg_probe(): > > priv->resets = devm_kcalloc(dev, max_num_reset_ids, > sizeof(*priv->resets), GFP_KERNEL); > for (i = 0; i < ARRAY_SIZE(info->resets); i++) { > id = RST_ID(info->resets[i].reset_index, info->resets[i].reset_bit); > priv->resets[id] = info->resets[i]; > } > > BTW, for option B (and for the current code in v4), > rzv2h_cpg_reset_xlate() should validate that the entry is non-empty. > > I hope this is more clear? > Yes, thanks for the clarification. I will go with option A, so we don't waste memory. Cheers, Prabhakar