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-rw-r--r--target/linux/brcm2708/patches-4.4/0581-clk-bcm-Support-rate-change-propagation-on-bcm2835-c.patch129
1 files changed, 129 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0581-clk-bcm-Support-rate-change-propagation-on-bcm2835-c.patch b/target/linux/brcm2708/patches-4.4/0581-clk-bcm-Support-rate-change-propagation-on-bcm2835-c.patch
new file mode 100644
index 0000000..bd7405e
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0581-clk-bcm-Support-rate-change-propagation-on-bcm2835-c.patch
@@ -0,0 +1,129 @@
+From e75f021850a698fec611538e8ff293c22a4604f5 Mon Sep 17 00:00:00 2001
+From: Boris Brezillon <boris.brezillon@free-electrons.com>
+Date: Thu, 1 Dec 2016 22:00:19 +0100
+Subject: [PATCH] clk: bcm: Support rate change propagation on bcm2835 clocks
+
+Some peripheral clocks, like the VEC (Video EnCoder) clock need to be set
+to a precise rate (in our case 108MHz). With the current implementation,
+where peripheral clocks are not allowed to forward rate change requests
+to their parents, it is impossible to match this requirement unless the
+bootloader has configured things correctly, or a specific rate has been
+assigned through the DT (with the assigned-clk-rates property).
+
+Add a new field to struct bcm2835_clock_data to specify which parent
+clocks accept rate change propagation, and support set rate propagation
+in bcm2835_clock_determine_rate().
+
+Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
+Reviewed-by: Eric Anholt <eric@anholt.net>
+Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
+(cherry picked from commit 155e8b3b0ee320ae866b97dd31eba8a1f080a772)
+---
+ drivers/clk/bcm/clk-bcm2835.c | 67 ++++++++++++++++++++++++++++++++++++++++---
+ 1 file changed, 63 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
+index 3fbd2e8..5f0e2f3 100644
+--- a/drivers/clk/bcm/clk-bcm2835.c
++++ b/drivers/clk/bcm/clk-bcm2835.c
+@@ -457,6 +457,9 @@ struct bcm2835_clock_data {
+ const char *const *parents;
+ int num_mux_parents;
+
++ /* Bitmap encoding which parents accept rate change propagation. */
++ unsigned int set_rate_parent;
++
+ u32 ctl_reg;
+ u32 div_reg;
+
+@@ -1055,10 +1058,60 @@ bcm2835_clk_is_pllc(struct clk_hw *hw)
+ return strncmp(clk_hw_get_name(hw), "pllc", 4) == 0;
+ }
+
++static unsigned long bcm2835_clock_choose_div_and_prate(struct clk_hw *hw,
++ int parent_idx,
++ unsigned long rate,
++ u32 *div,
++ unsigned long *prate)
++{
++ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
++ struct bcm2835_cprman *cprman = clock->cprman;
++ const struct bcm2835_clock_data *data = clock->data;
++ unsigned long best_rate;
++ u32 curdiv, mindiv, maxdiv;
++ struct clk_hw *parent;
++
++ parent = clk_hw_get_parent_by_index(hw, parent_idx);
++
++ if (!(BIT(parent_idx) & data->set_rate_parent)) {
++ *prate = clk_hw_get_rate(parent);
++ *div = bcm2835_clock_choose_div(hw, rate, *prate, true);
++
++ return bcm2835_clock_rate_from_divisor(clock, *prate,
++ *div);
++ }
++
++ if (data->frac_bits)
++ dev_warn(cprman->dev,
++ "frac bits are not used when propagating rate change");
++
++ /* clamp to min divider of 2 if we're dealing with a mash clock */
++ mindiv = data->is_mash_clock ? 2 : 1;
++ maxdiv = BIT(data->int_bits) - 1;
++
++ /* TODO: Be smart, and only test a subset of the available divisors. */
++ for (curdiv = mindiv; curdiv <= maxdiv; curdiv++) {
++ unsigned long tmp_rate;
++
++ tmp_rate = clk_hw_round_rate(parent, rate * curdiv);
++ tmp_rate /= curdiv;
++ if (curdiv == mindiv ||
++ (tmp_rate > best_rate && tmp_rate <= rate))
++ best_rate = tmp_rate;
++
++ if (best_rate == rate)
++ break;
++ }
++
++ *div = curdiv << CM_DIV_FRAC_BITS;
++ *prate = curdiv * best_rate;
++
++ return best_rate;
++}
++
+ static int bcm2835_clock_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+ {
+- struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ struct clk_hw *parent, *best_parent = NULL;
+ bool current_parent_is_pllc;
+ unsigned long rate, best_rate = 0;
+@@ -1086,9 +1139,8 @@ static int bcm2835_clock_determine_rate(struct clk_hw *hw,
+ if (bcm2835_clk_is_pllc(parent) && !current_parent_is_pllc)
+ continue;
+
+- prate = clk_hw_get_rate(parent);
+- div = bcm2835_clock_choose_div(hw, req->rate, prate, true);
+- rate = bcm2835_clock_rate_from_divisor(clock, prate, div);
++ rate = bcm2835_clock_choose_div_and_prate(hw, i, req->rate,
++ &div, &prate);
+ if (rate > best_rate && rate <= req->rate) {
+ best_parent = parent;
+ best_prate = prate;
+@@ -1308,6 +1360,13 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman,
+ if ((cprman_read(cprman, data->ctl_reg) & CM_ENABLE) == 0)
+ init.flags &= ~CLK_IS_CRITICAL;
+
++ /*
++ * Pass the CLK_SET_RATE_PARENT flag if we are allowed to propagate
++ * rate changes on at least of the parents.
++ */
++ if (data->set_rate_parent)
++ init.flags |= CLK_SET_RATE_PARENT;
++
+ if (data->is_vpu_clock) {
+ init.ops = &bcm2835_vpu_clock_clk_ops;
+ } else {
+--
+2.1.4
+