* Re: [PATCH 5.15] Revert "drivers: clk: zynqmp: update divider round rate logic"
2024-11-25 16:09 [PATCH 5.15] Revert "drivers: clk: zynqmp: update divider round rate logic" jguittet.opensource
@ 2024-11-25 16:22 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2024-11-25 16:22 UTC (permalink / raw)
To: stable; +Cc: jguittet.opensource, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: 1fe15be1fb613534ecbac5f8c3f8744f757d237d
WARNING: Author mismatch between patch and upstream commit:
Backport author: jguittet.opensource@witekio.com
Commit author: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (exact SHA1)
6.6.y | Present (different SHA1: 37b67480609f)
6.1.y | Present (different SHA1: c249ef9d0978)
5.15.y | Present (different SHA1: 9117fc44fd3a)
Note: The patch differs from the upstream commit:
---
--- - 2024-11-25 11:13:15.044326187 -0500
+++ /tmp/tmp.qTmzowaD8e 2024-11-25 11:13:15.035746470 -0500
@@ -1,108 +1,108 @@
-Currently zynqmp divider round rate is considering single parent and
-calculating rate and parent rate accordingly. But if divider clock flag
-is set to SET_RATE_PARENT then its not trying to traverse through all
-parent rate and not selecting best parent rate from that. So use common
-divider_round_rate() which is traversing through all clock parents and
-its rate and calculating proper parent rate.
+This reverts commit 9117fc44fd3a9538261e530ba5a022dfc9519620 which is
+commit 1fe15be1fb613534ecbac5f8c3f8744f757d237d upstream.
-Fixes: 3fde0e16d016 ("drivers: clk: Add ZynqMP clock driver")
-Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
-Link: https://lore.kernel.org/r/20231129112916.23125-3-jay.buddhabhatti@amd.com
-Signed-off-by: Stephen Boyd <sboyd@kernel.org>
+It is reported to cause regressions in the 5.15.y tree, so revert it for
+now.
+
+Link: https://www.spinics.net/lists/kernel/msg5397998.html
+Signed-off-by: Joel Guittet <jguittet.opensource@witekio.com>
---
- drivers/clk/zynqmp/divider.c | 66 +++---------------------------------
- 1 file changed, 5 insertions(+), 61 deletions(-)
+ drivers/clk/zynqmp/divider.c | 66 +++++++++++++++++++++++++++++++++---
+ 1 file changed, 61 insertions(+), 5 deletions(-)
diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c
-index 33a3b2a226595..5a00487ae408b 100644
+index e25c76ff2739..47a199346ddf 100644
--- a/drivers/clk/zynqmp/divider.c
+++ b/drivers/clk/zynqmp/divider.c
-@@ -110,52 +110,6 @@ static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
+@@ -110,6 +110,52 @@ static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
return DIV_ROUND_UP_ULL(parent_rate, value);
}
--static void zynqmp_get_divider2_val(struct clk_hw *hw,
-- unsigned long rate,
-- struct zynqmp_clk_divider *divider,
-- u32 *bestdiv)
--{
-- int div1;
-- int div2;
-- long error = LONG_MAX;
-- unsigned long div1_prate;
-- struct clk_hw *div1_parent_hw;
-- struct zynqmp_clk_divider *pdivider;
-- struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw);
--
-- if (!div2_parent_hw)
-- return;
--
-- pdivider = to_zynqmp_clk_divider(div2_parent_hw);
-- if (!pdivider)
-- return;
--
-- div1_parent_hw = clk_hw_get_parent(div2_parent_hw);
-- if (!div1_parent_hw)
-- return;
--
-- div1_prate = clk_hw_get_rate(div1_parent_hw);
-- *bestdiv = 1;
-- for (div1 = 1; div1 <= pdivider->max_div;) {
-- for (div2 = 1; div2 <= divider->max_div;) {
-- long new_error = ((div1_prate / div1) / div2) - rate;
--
-- if (abs(new_error) < abs(error)) {
-- *bestdiv = div2;
-- error = new_error;
-- }
-- if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
-- div2 = div2 << 1;
-- else
-- div2++;
-- }
-- if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO)
-- div1 = div1 << 1;
-- else
-- div1++;
-- }
--}
--
++static void zynqmp_get_divider2_val(struct clk_hw *hw,
++ unsigned long rate,
++ struct zynqmp_clk_divider *divider,
++ u32 *bestdiv)
++{
++ int div1;
++ int div2;
++ long error = LONG_MAX;
++ unsigned long div1_prate;
++ struct clk_hw *div1_parent_hw;
++ struct zynqmp_clk_divider *pdivider;
++ struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw);
++
++ if (!div2_parent_hw)
++ return;
++
++ pdivider = to_zynqmp_clk_divider(div2_parent_hw);
++ if (!pdivider)
++ return;
++
++ div1_parent_hw = clk_hw_get_parent(div2_parent_hw);
++ if (!div1_parent_hw)
++ return;
++
++ div1_prate = clk_hw_get_rate(div1_parent_hw);
++ *bestdiv = 1;
++ for (div1 = 1; div1 <= pdivider->max_div;) {
++ for (div2 = 1; div2 <= divider->max_div;) {
++ long new_error = ((div1_prate / div1) / div2) - rate;
++
++ if (abs(new_error) < abs(error)) {
++ *bestdiv = div2;
++ error = new_error;
++ }
++ if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
++ div2 = div2 << 1;
++ else
++ div2++;
++ }
++ if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO)
++ div1 = div1 << 1;
++ else
++ div1++;
++ }
++}
++
/**
* zynqmp_clk_divider_round_rate() - Round rate of divider clock
* @hw: handle between common and hardware-specific interfaces
-@@ -174,6 +128,7 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
+@@ -128,7 +174,6 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
u32 div_type = divider->div_type;
u32 bestdiv;
int ret;
-+ u8 width;
+- u8 width;
/* if read only, just return current value */
if (divider->flags & CLK_DIVIDER_READ_ONLY) {
-@@ -193,23 +148,12 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
+@@ -148,12 +193,23 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
}
-- bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);
--
-- /*
-- * In case of two divisors, compute best divider values and return
-- * divider2 value based on compute value. div1 will be automatically
-- * set to optimum based on required total divider value.
-- */
-- if (div_type == TYPE_DIV2 &&
-- (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
-- zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);
-- }
-+ width = fls(divider->max_div);
-
-- if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)
-- bestdiv = rate % *prate ? 1 : bestdiv;
-+ rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags);
-
-- bestdiv = min_t(u32, bestdiv, divider->max_div);
-- *prate = rate * bestdiv;
-+ if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
-+ *prate = rate;
+- width = fls(divider->max_div);
++ bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);
++
++ /*
++ * In case of two divisors, compute best divider values and return
++ * divider2 value based on compute value. div1 will be automatically
++ * set to optimum based on required total divider value.
++ */
++ if (div_type == TYPE_DIV2 &&
++ (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
++ zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);
++ }
+
+- rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags);
++ if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)
++ bestdiv = rate % *prate ? 1 : bestdiv;
+
+- if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
+- *prate = rate;
++ bestdiv = min_t(u32, bestdiv, divider->max_div);
++ *prate = rate * bestdiv;
return rate;
}
+--
+2.25.1
+
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y | Success | Success |
^ permalink raw reply [flat|nested] 2+ messages in thread