| Message ID | 805048a548031cafc890e6ea06ee773bdfb199d0.1499197129.git-series.plaes@plaes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jul 5, 2017 at 4:04 AM, Priit Laes <plaes@plaes.org> wrote: > SATA clock on sun4i/sun7i is of type (parent) / M / 6 where > 6 is fixed post-divider. > > Signed-off-by: Priit Laes <plaes@plaes.org> Reviewed-by: Chen-Yu Tsai <wens@csie.org>
On Tue, Jul 04, 2017 at 11:04:56PM +0300, Priit Laes wrote: > SATA clock on sun4i/sun7i is of type (parent) / M / 6 where > 6 is fixed post-divider. > > Signed-off-by: Priit Laes <plaes@plaes.org> > --- > drivers/clk/sunxi-ng/ccu_div.c | 18 ++++++++++++++++-- > drivers/clk/sunxi-ng/ccu_div.h | 3 ++- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/drivers/clk/sunxi-ng/ccu_div.c b/drivers/clk/sunxi-ng/ccu_div.c > index c0e5c10..054b12a 100644 > --- a/drivers/clk/sunxi-ng/ccu_div.c > +++ b/drivers/clk/sunxi-ng/ccu_div.c > @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct ccu_mux_internal *mux, > { > struct ccu_div *cd = data; > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + rate /= cd->fixed_post_div; > + > return divider_round_rate_parent(&cd->common.hw, parent, > rate, parent_rate, > cd->div.table, cd->div.width, This doesn't work. The rate formula is rate = parent / div / 6 Which is equivalent to div = rate * 6 / parent You should be multiplying the rate, not dividing it (or dividing the parent, but then you'll also need to multiply it back after the call to divider_round_rate_parent). Consider this, some driver wants to set a rate of 100MHz on this clock. The parent is 1.2GHz, and you have your postdiv of 6. The divider we want to compute is 2, obviously. You're doing here: rate / 6 = parent / div Which means that you'll end up trying to find the divider between 1.2GHz and 16.6666MHz, which is going to be 72. > @@ -62,8 +65,13 @@ static unsigned long ccu_div_recalc_rate(struct clk_hw *hw, > parent_rate = ccu_mux_helper_apply_prediv(&cd->common, &cd->mux, -1, > parent_rate); > > - return divider_recalc_rate(hw, parent_rate, val, cd->div.table, > - cd->div.flags); > + val = divider_recalc_rate(hw, parent_rate, val, cd->div.table, > + cd->div.flags); > + > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + val /= cd->fixed_post_div; > + > + return val; > } > > static int ccu_div_determine_rate(struct clk_hw *hw, > @@ -71,6 +79,9 @@ static int ccu_div_determine_rate(struct clk_hw *hw, > { > struct ccu_div *cd = hw_to_ccu_div(hw); > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + req->rate *= cd->fixed_post_div; > + I guess this is why you never really saw the issue. Combined with your division in ccu_div_round_rate, it produces the exact rate you were given as an argument. > return ccu_mux_helper_determine_rate(&cd->common, &cd->mux, > req, ccu_div_round_rate, cd); > } > @@ -89,6 +100,9 @@ static int ccu_div_set_rate(struct clk_hw *hw, unsigned long rate, > val = divider_get_val(rate, parent_rate, cd->div.table, cd->div.width, > cd->div.flags); > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + val /= cd->fixed_post_div; > + If you multiply the rate before calling divider_get_val, you won't have to do the division of the divider, with all the rounding weirdness it might create. Maxime
Hey Plaes, On 04-07-17 22:04, Priit Laes wrote: > SATA clock on sun4i/sun7i is of type (parent) / M / 6 where > 6 is fixed post-divider. > > Signed-off-by: Priit Laes <plaes@plaes.org> > --- > drivers/clk/sunxi-ng/ccu_div.c | 18 ++++++++++++++++-- > drivers/clk/sunxi-ng/ccu_div.h | 3 ++- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/drivers/clk/sunxi-ng/ccu_div.c b/drivers/clk/sunxi-ng/ccu_div.c > index c0e5c10..054b12a 100644 > --- a/drivers/clk/sunxi-ng/ccu_div.c > +++ b/drivers/clk/sunxi-ng/ccu_div.c > @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct ccu_mux_internal *mux, > { > struct ccu_div *cd = data; > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + rate /= cd->fixed_post_div; > + > return divider_round_rate_parent(&cd->common.hw, parent, > rate, parent_rate, > cd->div.table, cd->div.width, > @@ -62,8 +65,13 @@ static unsigned long ccu_div_recalc_rate(struct clk_hw *hw, > parent_rate = ccu_mux_helper_apply_prediv(&cd->common, &cd->mux, -1, > parent_rate); > > - return divider_recalc_rate(hw, parent_rate, val, cd->div.table, > - cd->div.flags); > + val = divider_recalc_rate(hw, parent_rate, val, cd->div.table, > + cd->div.flags); > + > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + val /= cd->fixed_post_div; > + > + return val; > } > > static int ccu_div_determine_rate(struct clk_hw *hw, > @@ -71,6 +79,9 @@ static int ccu_div_determine_rate(struct clk_hw *hw, > { > struct ccu_div *cd = hw_to_ccu_div(hw); > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + req->rate *= cd->fixed_post_div; > + > return ccu_mux_helper_determine_rate(&cd->common, &cd->mux, > req, ccu_div_round_rate, cd); > } > @@ -89,6 +100,9 @@ static int ccu_div_set_rate(struct clk_hw *hw, unsigned long rate, > val = divider_get_val(rate, parent_rate, cd->div.table, cd->div.width, > cd->div.flags); > > + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) > + val /= cd->fixed_post_div; > + > spin_lock_irqsave(cd->common.lock, flags); > > reg = readl(cd->common.base + cd->common.reg); > diff --git a/drivers/clk/sunxi-ng/ccu_div.h b/drivers/clk/sunxi-ng/ccu_div.h > index 08d0744..f3a5028 100644 > --- a/drivers/clk/sunxi-ng/ccu_div.h > +++ b/drivers/clk/sunxi-ng/ccu_div.h > @@ -86,9 +86,10 @@ struct ccu_div_internal { > struct ccu_div { > u32 enable; > > - struct ccu_div_internal div; > + struct ccu_div_internal div; > struct ccu_mux_internal mux; > struct ccu_common common; > + unsigned int fixed_post_div; > }; > > #define SUNXI_CCU_DIV_TABLE_WITH_GATE(_struct, _name, _parent, _reg, \ >
diff --git a/drivers/clk/sunxi-ng/ccu_div.c b/drivers/clk/sunxi-ng/ccu_div.c index c0e5c10..054b12a 100644 --- a/drivers/clk/sunxi-ng/ccu_div.c +++ b/drivers/clk/sunxi-ng/ccu_div.c @@ -21,6 +21,9 @@ static unsigned long ccu_div_round_rate(struct ccu_mux_internal *mux, { struct ccu_div *cd = data; + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) + rate /= cd->fixed_post_div; + return divider_round_rate_parent(&cd->common.hw, parent, rate, parent_rate, cd->div.table, cd->div.width, @@ -62,8 +65,13 @@ static unsigned long ccu_div_recalc_rate(struct clk_hw *hw, parent_rate = ccu_mux_helper_apply_prediv(&cd->common, &cd->mux, -1, parent_rate); - return divider_recalc_rate(hw, parent_rate, val, cd->div.table, - cd->div.flags); + val = divider_recalc_rate(hw, parent_rate, val, cd->div.table, + cd->div.flags); + + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) + val /= cd->fixed_post_div; + + return val; } static int ccu_div_determine_rate(struct clk_hw *hw, @@ -71,6 +79,9 @@ static int ccu_div_determine_rate(struct clk_hw *hw, { struct ccu_div *cd = hw_to_ccu_div(hw); + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) + req->rate *= cd->fixed_post_div; + return ccu_mux_helper_determine_rate(&cd->common, &cd->mux, req, ccu_div_round_rate, cd); } @@ -89,6 +100,9 @@ static int ccu_div_set_rate(struct clk_hw *hw, unsigned long rate, val = divider_get_val(rate, parent_rate, cd->div.table, cd->div.width, cd->div.flags); + if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV) + val /= cd->fixed_post_div; + spin_lock_irqsave(cd->common.lock, flags); reg = readl(cd->common.base + cd->common.reg); diff --git a/drivers/clk/sunxi-ng/ccu_div.h b/drivers/clk/sunxi-ng/ccu_div.h index 08d0744..f3a5028 100644 --- a/drivers/clk/sunxi-ng/ccu_div.h +++ b/drivers/clk/sunxi-ng/ccu_div.h @@ -86,9 +86,10 @@ struct ccu_div_internal { struct ccu_div { u32 enable; - struct ccu_div_internal div; + struct ccu_div_internal div; struct ccu_mux_internal mux; struct ccu_common common; + unsigned int fixed_post_div; }; #define SUNXI_CCU_DIV_TABLE_WITH_GATE(_struct, _name, _parent, _reg, \
SATA clock on sun4i/sun7i is of type (parent) / M / 6 where 6 is fixed post-divider. Signed-off-by: Priit Laes <plaes@plaes.org> --- drivers/clk/sunxi-ng/ccu_div.c | 18 ++++++++++++++++-- drivers/clk/sunxi-ng/ccu_div.h | 3 ++- 2 files changed, 18 insertions(+), 3 deletions(-)