When the firmware code is disabled, the incomplete error handling
in the clk driver causes compile-time warnings:
drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
147 | rate = parent_rate * fbdiv;
| ~~~~~~~~~~~~^~~~~~~
In function 'zynqmp_pll_get_mode',
inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
61 | return ret_payload[1];
| ~~~~~~~~~~~^~~
drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
53 | u32 ret_payload[PAYLOAD_ARG_CNT];
| ^~~~~~~~~~~
drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
57 | return val;
| ^~~
As it was apparently intentional to support this for compile testing
purposes, change the code to have just enough error handling for the
compiler to not notice the remaining bugs.
Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
Co-developed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Michal Simek <[email protected]>
---
Changes in v3:
- Also check PLL_MODE_ERROR return in zynqmp_pll_recalc_rate() - reported
by Quanyang
- Change Arnd's authorhip based on our discussing at
https://lore.kernel.org/r/CAK8P3a1twOhC8DFxpLxpk8bcy0+JfGZUSE9bX4tdMetVLGTcSQ@mail.gmail.com
Changes in v2:
Based on discussion here
Link: https://lore.kernel.org/r/[email protected]
I have updated error return value which I got from clock core based on
error cases.
zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
clk_core_get_parent_by_index() where num_parents is incorrect index.
Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.
zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
default rate. But maybe -1ul which was used by Arnd is also good option.
---
drivers/clk/zynqmp/clk-mux-zynqmp.c | 10 ++++++++--
drivers/clk/zynqmp/pll.c | 22 ++++++++++++++++------
2 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
index 06194149be83..d576c900dee0 100644
--- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
+++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
@@ -38,7 +38,7 @@ struct zynqmp_clk_mux {
* zynqmp_clk_mux_get_parent() - Get parent of clock
* @hw: handle between common and hardware-specific interfaces
*
- * Return: Parent index
+ * Return: Parent index on success or number of parents in case of error
*/
static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
{
@@ -50,9 +50,15 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
ret = zynqmp_pm_clock_getparent(clk_id, &val);
- if (ret)
+ if (ret) {
pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
__func__, clk_name, ret);
+ /*
+ * clk_core_get_parent_by_index() takes num_parents as incorrect
+ * index which is exactly what I want to return here
+ */
+ return clk_hw_get_num_parents(hw);
+ }
return val;
}
diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
index abe6afbf3407..e025581f0d54 100644
--- a/drivers/clk/zynqmp/pll.c
+++ b/drivers/clk/zynqmp/pll.c
@@ -31,8 +31,9 @@ struct zynqmp_pll {
#define PS_PLL_VCO_MAX 3000000000UL
enum pll_mode {
- PLL_MODE_INT,
- PLL_MODE_FRAC,
+ PLL_MODE_INT = 0,
+ PLL_MODE_FRAC = 1,
+ PLL_MODE_ERROR = 2,
};
#define FRAC_OFFSET 0x8
@@ -54,9 +55,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
int ret;
ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
- if (ret)
+ if (ret) {
pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
__func__, clk_name, ret);
+ return PLL_MODE_ERROR;
+ }
return ret_payload[1];
}
@@ -126,7 +129,7 @@ static long zynqmp_pll_round_rate(struct clk_hw *hw, unsigned long rate,
* @hw: Handle between common and hardware-specific interfaces
* @parent_rate: Clock frequency of parent clock
*
- * Return: Current clock frequency
+ * Return: Current clock frequency or 0 in case of error
*/
static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
@@ -138,14 +141,21 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
unsigned long rate, frac;
u32 ret_payload[PAYLOAD_ARG_CNT];
int ret;
+ enum pll_mode mode;
ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
- if (ret)
+ if (ret) {
pr_warn_once("%s() get divider failed for %s, ret = %d\n",
__func__, clk_name, ret);
+ return 0ul;
+ }
+
+ mode = zynqmp_pll_get_mode(hw);
+ if (mode == PLL_MODE_ERROR)
+ return 0ul;
rate = parent_rate * fbdiv;
- if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
+ if (mode == PLL_MODE_FRAC) {
zynqmp_pm_get_pll_frac_data(clk_id, ret_payload);
data = ret_payload[1];
frac = (parent_rate * data) / FRAC_DIV;
--
2.32.0
Quoting Michal Simek (2021-06-22 03:15:11)
> When the firmware code is disabled, the incomplete error handling
> in the clk driver causes compile-time warnings:
>
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
> 147 | rate = parent_rate * fbdiv;
> | ~~~~~~~~~~~~^~~~~~~
> In function 'zynqmp_pll_get_mode',
> inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
> 61 | return ret_payload[1];
> | ~~~~~~~~~~~^~~
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
> 53 | u32 ret_payload[PAYLOAD_ARG_CNT];
> | ^~~~~~~~~~~
> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
> 57 | return val;
> | ^~~
>
> As it was apparently intentional to support this for compile testing
> purposes, change the code to have just enough error handling for the
> compiler to not notice the remaining bugs.
>
> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
> Co-developed-by: Arnd Bergmann <[email protected]>
> Signed-off-by: Michal Simek <[email protected]>
> ---
Applied to clk-next. I see this fixes a bug in this upcoming release but
I'm sure we can pick this back to stable tree in a week or so once the
merge window opens. It's not like this is fixing anything besides
compile testing anyway.