On Thu, Jul 12, 2018 at 11:52:31AM +0100, Jon Hunter wrote:
>
> On 11/07/18 15:39, Aapo Vienamo wrote:
> > From: Peter De-Schrijver <pdeschrij...@nvidia.com>
> >
> > Add a clock type to model the sdmmc switch divider clocks which have paths
> > to source clocks bypassing the divider (Low Jitter paths). These
> > are handled by selecting the lj path when the divider is 1 (ie the
> > rate is the parent rate), otherwise the normal path with divider
> > will be selected. Otherwise this clock behaves as a normal peripheral
> > clock.
> >
> > Signed-off-by: Peter De-Schrijver <pdeschrij...@nvidia.com>
> > Signed-off-by: Aapo Vienamo <avien...@nvidia.com>
> > Acked-by: Peter De Schrijver <pdeschrij...@nvidia.com>
> > ---
> > drivers/clk/tegra/Makefile | 1 +
> > drivers/clk/tegra/clk-sdmmc-mux.c | 249
> > ++++++++++++++++++++++++++++++++++++++
> > drivers/clk/tegra/clk.h | 26 ++++
> > 3 files changed, 276 insertions(+)
> > create mode 100644 drivers/clk/tegra/clk-sdmmc-mux.c
> >
> > diff --git a/drivers/clk/tegra/Makefile b/drivers/clk/tegra/Makefile
> > index c79319d..8975f88 100644
> > --- a/drivers/clk/tegra/Makefile
> > +++ b/drivers/clk/tegra/Makefile
> > @@ -8,6 +8,7 @@ obj-y +=
> > clk-periph-fixed.o
> > obj-y += clk-periph-gate.o
> > obj-y += clk-pll.o
> > obj-y += clk-pll-out.o
> > +obj-y += clk-sdmmc-mux.o
> > obj-y += clk-super.o
> > obj-y += clk-tegra-audio.o
> > obj-y += clk-tegra-periph.o
> > diff --git a/drivers/clk/tegra/clk-sdmmc-mux.c
> > b/drivers/clk/tegra/clk-sdmmc-mux.c
> > new file mode 100644
> > index 0000000..9566754
> > --- /dev/null
> > +++ b/drivers/clk/tegra/clk-sdmmc-mux.c
> > @@ -0,0 +1,249 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018 NVIDIA CORPORATION. All rights reserved.
> > + *
> > + * based on clk-mux.c
> > + *
> > + * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.ha...@pengutronix.de>
> > + * Copyright (C) 2011 Richard Zhao, Linaro <richard.z...@linaro.org>
> > + * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd
> > <mturque...@linaro.org>
> > + *
> > + */
> > +
> > +#include <linux/clk-provider.h>
> > +#include <linux/err.h>
> > +#include <linux/types.h>
> > +
> > +#include "clk.h"
> > +
> > +#define DIV_MASK GENMASK(7, 0)
> > +#define MUX_SHIFT 29
> > +#define MUX_MASK GENMASK(MUX_SHIFT + 2, MUX_SHIFT)
> > +
> > +#define get_max_div(d) DIV_MASK
> > +#define get_div_field(val) ((val) & DIV_MASK)
> > +#define get_mux_field(val) (((val) & MUX_MASK) >> MUX_SHIFT)
> > +
> > +static const char * const mux_sdmmc_parents[] = {
> > + "pll_p", "pll_c4_out2", "pll_c4_out0", "pll_c4_out1", "clk_m"
> > +};
> > +
> > +static const u8 mux_lj_idx[] = {
> > + [0] = 0, [1] = 1, [2] = 2, [3] = 5, [4] = 6
> > +};
> > +
> > +static const u8 mux_non_lj_idx[] = {
> > + [0] = 0, [1] = 3, [2] = 7, [3] = 4, [4] = 6
> > +};
> > +
> > +static u8 clk_sdmmc_mux_get_parent(struct clk_hw *hw)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + int num_parents, i;
> > + u32 src, val;
> > + const u8 *mux_idx;
> > +
> > + num_parents = clk_hw_get_num_parents(hw);
> > +
> > + val = readl_relaxed(sdmmc_mux->reg);
> > + src = get_mux_field(val);
> > + if (get_div_field(val))
> > + mux_idx = mux_non_lj_idx;
> > + else
> > + mux_idx = mux_lj_idx;
> > +
> > + for (i = 0; i < num_parents; i++) {
> > + if (mux_idx[i] == src)
> > + return i;
> > + }
> > +
> > + WARN(1, "Unknown parent selector %d\n", src);
> > +
> > + return 0;
> > +}
> > +
> > +static int clk_sdmmc_mux_set_parent(struct clk_hw *hw, u8 index)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + u32 val;
> > +
> > +
> > + val = readl_relaxed(sdmmc_mux->reg);
> > + if (get_div_field(val))
> > + index = mux_non_lj_idx[index];
> > + else
> > + index = mux_lj_idx[index];
> > +
> > + val &= ~MUX_MASK;
> > + val |= index << MUX_SHIFT;
> > +
> > + writel(val, sdmmc_mux->reg);
> > +
> > + return 0;
> > +}
> > +
> > +static unsigned long clk_sdmmc_mux_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + u32 val;
> > + int div, mul;
> > + u64 rate = parent_rate;
> > +
> > + val = readl_relaxed(sdmmc_mux->reg);
> > + div = get_div_field(val);
> > +
> > + mul = 2;
> > + div += mul;
> > +
> > + rate *= mul;
> > + rate += div - 1;
> > + do_div(rate, div);
> > +
> > + return rate;
> > +}
> > +
> > +static int clk_sdmmc_mux_determine_rate(struct clk_hw *hw,
> > + struct clk_rate_request *req)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + int div, mul;
> > + unsigned long output_rate = req->best_parent_rate;
> > +
> > + req->rate = max(req->rate, req->min_rate);
> > + req->rate = min(req->rate, req->max_rate);
> > +
> > + if (!req->rate)
> > + return output_rate;
> > +
> > + div = div_frac_get(req->rate, output_rate, 8, 1, sdmmc_mux->div_flags);
> > + if (div < 0)
> > + div = 0;
> > +
> > + mul = 2;
>
> This multiplier never changes and so maybe more appropriate to add a
> #define TEGRA_SDMMC_MULT or something for this function and the above.
>
> > + if (sdmmc_mux->div_flags & TEGRA_DIVIDER_ROUND_UP)
> > + req->rate = DIV_ROUND_UP(output_rate * mul, div + mul);
> > + else
> > + req->rate = output_rate * mul / (div + mul);
> > +
> > + return 0;
> > +}
> > +
> > +static int clk_sdmmc_mux_set_rate(struct clk_hw *hw, unsigned long rate,
> > + unsigned long parent_rate)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + int div;
> > + unsigned long flags = 0;
> > + u32 val;
> > + u8 src;
> > +
> > + div = div_frac_get(rate, parent_rate, 8, 1, sdmmc_mux->div_flags);
> > + if (div < 0)
> > + return div;
> > +
> > + if (sdmmc_mux->lock)
> > + spin_lock_irqsave(sdmmc_mux->lock, flags);
> > +
> > + src = clk_sdmmc_mux_get_parent(hw);
> > + if (div)
> > + src = mux_non_lj_idx[src];
> > + else
> > + src = mux_lj_idx[src];
> > +
> > + val = src << MUX_SHIFT;
> > + val |= div;
> > + writel(val, sdmmc_mux->reg);
> > + fence_udelay(2, sdmmc_mux->reg);
> > +
> > + if (sdmmc_mux->lock)
> > + spin_unlock_irqrestore(sdmmc_mux->lock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static int clk_sdmmc_mux_is_enabled(struct clk_hw *hw)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
> > + struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
> > +
> > + __clk_hw_set_clk(gate_hw, hw);
> > +
> > + return gate_ops->is_enabled(gate_hw);
> > +}
> > +
> > +static int clk_sdmmc_mux_enable(struct clk_hw *hw)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
> > + struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
> > +
> > + __clk_hw_set_clk(gate_hw, hw);
> > +
> > + return gate_ops->enable(gate_hw);
>
> Nit-pick ... extra space.
>
> > +}
> > +
> > +static void clk_sdmmc_mux_disable(struct clk_hw *hw)
> > +{
> > + struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
> > + const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
> > + struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
> > +
> > + gate_ops->disable(gate_hw);
> > +}
> > +
> > +static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
> > + .get_parent = clk_sdmmc_mux_get_parent,
> > + .set_parent = clk_sdmmc_mux_set_parent,
> > + .determine_rate = clk_sdmmc_mux_determine_rate,
> > + .recalc_rate = clk_sdmmc_mux_recalc_rate,
> > + .set_rate = clk_sdmmc_mux_set_rate,
> > + .is_enabled = clk_sdmmc_mux_is_enabled,
> > + .enable = clk_sdmmc_mux_enable,
> > + .disable = clk_sdmmc_mux_disable,
> > +};
> > +
> > +struct clk *tegra_clk_register_sdmmc_mux_div(const char *name,
> > + void __iomem *clk_base, u32 offset, u32 clk_num, u8 div_flags,
> > + unsigned long flags, void *lock)
> > +{
> > + struct clk *clk;
> > + struct clk_init_data init;
> > + const struct tegra_clk_periph_regs *bank;
> > + struct tegra_sdmmc_mux *sdmmc_mux;
> > +
> > + init.ops = &tegra_clk_sdmmc_mux_ops;
> > + init.name = name;
> > + init.flags = flags;
>
> Flags do not appear to be passed by the callers currently. Do we need
> to pass these or could we set to 0 here?
>
This is what we do for all other peripheral clocks. I don't think it makes
much sense to deviate from that pattern for this case.
> > + init.parent_names = mux_sdmmc_parents;
> > + init.num_parents = ARRAY_SIZE(mux_sdmmc_parents);
> > +
> > + bank = get_reg_bank(clk_num);
> > + if (!bank)
> > + return ERR_PTR(-EINVAL);
> > +
> > + sdmmc_mux = kzalloc(sizeof(*sdmmc_mux), GFP_KERNEL);
> > + if (!sdmmc_mux)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + /* Data in .init is copied by clk_register(), so stack variable OK */
> > + sdmmc_mux->hw.init = &init;
> > + sdmmc_mux->reg = clk_base + offset;
> > + sdmmc_mux->lock = lock;
>
> Does not look like this lock is never used. The callers pass NULL.
> Do we have plans to use this?
>
Same here. This is inline with what we do for other peripheral clocks even
though the vast majority never needs this.
> > + sdmmc_mux->gate.clk_base = clk_base;
> > + sdmmc_mux->gate.regs = bank;
> > + sdmmc_mux->gate.enable_refcnt = periph_clk_enb_refcnt;
> > + sdmmc_mux->gate.clk_num = clk_num;
> > + sdmmc_mux->gate.flags = TEGRA_PERIPH_ON_APB;
> > + sdmmc_mux->div_flags = div_flags;
>
> Callers set div_flags to TEGRA_DIVIDER_ROUND_UP. Does this need to
> be passed?
>
Not sure if this will always be the case.
Peter.
