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[PATCH] hwrng: airoha: Fix wait_for_completion_timeout return value check

Haotian Zhang posted 1 patch 1 week, 4 days ago 
drivers/char/hw_random/airoha-trng.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
[PATCH] hwrng: airoha: Fix wait_for_completion_timeout return value check
Posted by Haotian Zhang 1 week, 4 days ago 
wait_for_completion_timeout() returns an unsigned long
representing remaining jiffies, not an int. It returns
0 on timeout and a positive value on completion, never
a negative error code.

Change the type of ret to unsigned long, and update the
check to == 0 to correctly detect timeouts.

Fixes: e53ca8efcc5e ("hwrng: airoha - add support for Airoha EN7581 TRNG")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
---
 drivers/char/hw_random/airoha-trng.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/hw_random/airoha-trng.c b/drivers/char/hw_random/airoha-trng.c
index 1dbfa9505c21..3e94233e1389 100644
--- a/drivers/char/hw_random/airoha-trng.c
+++ b/drivers/char/hw_random/airoha-trng.c
@@ -76,7 +76,7 @@ static int airoha_trng_irq_unmask(struct airoha_trng *trng)
 static int airoha_trng_init(struct hwrng *rng)
 {
 	struct airoha_trng *trng = container_of(rng, struct airoha_trng, rng);
-	int ret;
+	unsigned long ret;
 	u32 val;
 
 	val = readl(trng->base + TRNG_NS_SEK_AND_DAT_EN);
@@ -88,7 +88,7 @@ static int airoha_trng_init(struct hwrng *rng)
 	writel(0, trng->base + TRNG_HEALTH_TEST_SW_RST);
 
 	ret = wait_for_completion_timeout(&trng->rng_op_done, BUSY_LOOP_TIMEOUT);
-	if (ret <= 0) {
+	if (ret == 0) {
 		dev_err(trng->dev, "Timeout waiting for Health Check\n");
 		airoha_trng_irq_mask(trng);
 		return -ENODEV;
-- 
2.50.1.windows.1
Re: [PATCH] hwrng: airoha: Fix wait_for_completion_timeout return value check
Posted by kernel test robot 1 week ago 
Hi Haotian,

kernel test robot noticed the following build warnings:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.18 next-20251212]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Haotian-Zhang/hwrng-airoha-Fix-wait_for_completion_timeout-return-value-check/20251208-161314
base:   char-misc/char-misc-testing
patch link:    https://lore.kernel.org/r/20251208080836.1010-1-vulab%40iscas.ac.cn
patch subject: [PATCH] hwrng: airoha: Fix wait_for_completion_timeout return value check
config: arm-randconfig-r072-20251210 (https://download.01.org/0day-ci/archive/20251212/202512121309.biSQJ5fC-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 12.5.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512121309.biSQJ5fC-lkp@intel.com/

New smatch warnings:
drivers/char/hw_random/airoha-trng.c:108 airoha_trng_init() warn: unsigned 'ret' is never less than zero.

Old smatch warnings:
drivers/char/hw_random/airoha-trng.c:117 airoha_trng_init() warn: unsigned 'ret' is never less than zero.

vim +/ret +108 drivers/char/hw_random/airoha-trng.c

e53ca8efcc5ec1 Christian Marangi 2024-10-17   75  
e53ca8efcc5ec1 Christian Marangi 2024-10-17   76  static int airoha_trng_init(struct hwrng *rng)
e53ca8efcc5ec1 Christian Marangi 2024-10-17   77  {
e53ca8efcc5ec1 Christian Marangi 2024-10-17   78  	struct airoha_trng *trng = container_of(rng, struct airoha_trng, rng);
cd62dba83f93a0 Haotian Zhang     2025-12-08   79  	unsigned long ret;
e53ca8efcc5ec1 Christian Marangi 2024-10-17   80  	u32 val;
e53ca8efcc5ec1 Christian Marangi 2024-10-17   81  
e53ca8efcc5ec1 Christian Marangi 2024-10-17   82  	val = readl(trng->base + TRNG_NS_SEK_AND_DAT_EN);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   83  	val |= RNG_EN;
e53ca8efcc5ec1 Christian Marangi 2024-10-17   84  	writel(val, trng->base + TRNG_NS_SEK_AND_DAT_EN);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   85  
e53ca8efcc5ec1 Christian Marangi 2024-10-17   86  	/* Set out of SW Reset */
e53ca8efcc5ec1 Christian Marangi 2024-10-17   87  	airoha_trng_irq_unmask(trng);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   88  	writel(0, trng->base + TRNG_HEALTH_TEST_SW_RST);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   89  
e53ca8efcc5ec1 Christian Marangi 2024-10-17   90  	ret = wait_for_completion_timeout(&trng->rng_op_done, BUSY_LOOP_TIMEOUT);
cd62dba83f93a0 Haotian Zhang     2025-12-08   91  	if (ret == 0) {
e53ca8efcc5ec1 Christian Marangi 2024-10-17   92  		dev_err(trng->dev, "Timeout waiting for Health Check\n");
e53ca8efcc5ec1 Christian Marangi 2024-10-17   93  		airoha_trng_irq_mask(trng);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   94  		return -ENODEV;
e53ca8efcc5ec1 Christian Marangi 2024-10-17   95  	}
e53ca8efcc5ec1 Christian Marangi 2024-10-17   96  
e53ca8efcc5ec1 Christian Marangi 2024-10-17   97  	/* Check if Health Test Failed */
e53ca8efcc5ec1 Christian Marangi 2024-10-17   98  	val = readl(trng->base + TRNG_HEALTH_TEST_STATUS);
e53ca8efcc5ec1 Christian Marangi 2024-10-17   99  	if (val & (RST_STARTUP_AP_TEST_FAIL | RST_STARTUP_RC_TEST_FAIL)) {
e53ca8efcc5ec1 Christian Marangi 2024-10-17  100  		dev_err(trng->dev, "Health Check fail: %s test fail\n",
e53ca8efcc5ec1 Christian Marangi 2024-10-17  101  			val & RST_STARTUP_AP_TEST_FAIL ? "AP" : "RC");
e53ca8efcc5ec1 Christian Marangi 2024-10-17  102  		return -ENODEV;
e53ca8efcc5ec1 Christian Marangi 2024-10-17  103  	}
e53ca8efcc5ec1 Christian Marangi 2024-10-17  104  
e53ca8efcc5ec1 Christian Marangi 2024-10-17  105  	/* Check if IP is ready */
e53ca8efcc5ec1 Christian Marangi 2024-10-17  106  	ret = readl_poll_timeout(trng->base + TRNG_IP_RDY, val,
e53ca8efcc5ec1 Christian Marangi 2024-10-17  107  				 val & SAMPLE_RDY, 10, 1000);
e53ca8efcc5ec1 Christian Marangi 2024-10-17 @108  	if (ret < 0) {
e53ca8efcc5ec1 Christian Marangi 2024-10-17  109  		dev_err(trng->dev, "Timeout waiting for IP ready");
e53ca8efcc5ec1 Christian Marangi 2024-10-17  110  		return -ENODEV;
e53ca8efcc5ec1 Christian Marangi 2024-10-17  111  	}
e53ca8efcc5ec1 Christian Marangi 2024-10-17  112  
e53ca8efcc5ec1 Christian Marangi 2024-10-17  113  	/* CNT_TRANS must be 0x80 for IP to be considered ready */
e53ca8efcc5ec1 Christian Marangi 2024-10-17  114  	ret = readl_poll_timeout(trng->base + TRNG_IP_RDY, val,
e53ca8efcc5ec1 Christian Marangi 2024-10-17  115  				 FIELD_GET(CNT_TRANS, val) == TRNG_CNT_TRANS_VALID,
e53ca8efcc5ec1 Christian Marangi 2024-10-17  116  				 10, 1000);
e53ca8efcc5ec1 Christian Marangi 2024-10-17  117  	if (ret < 0) {
e53ca8efcc5ec1 Christian Marangi 2024-10-17  118  		dev_err(trng->dev, "Timeout waiting for IP ready");
e53ca8efcc5ec1 Christian Marangi 2024-10-17  119  		return -ENODEV;
e53ca8efcc5ec1 Christian Marangi 2024-10-17  120  	}
e53ca8efcc5ec1 Christian Marangi 2024-10-17  121  
e53ca8efcc5ec1 Christian Marangi 2024-10-17  122  	return 0;
e53ca8efcc5ec1 Christian Marangi 2024-10-17  123  }
e53ca8efcc5ec1 Christian Marangi 2024-10-17  124  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH] hwrng: airoha: Fix wait_for_completion_timeout return value check
Posted by Martin Kaiser 1 week, 4 days ago 
Thus wrote Haotian Zhang (vulab@iscas.ac.cn):

> wait_for_completion_timeout() returns an unsigned long
> representing remaining jiffies, not an int. It returns
> 0 on timeout and a positive value on completion, never
> a negative error code.

> Change the type of ret to unsigned long, and update the
> check to == 0 to correctly detect timeouts.

> Fixes: e53ca8efcc5e ("hwrng: airoha - add support for Airoha EN7581 TRNG")
> Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
> ---
>  drivers/char/hw_random/airoha-trng.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

> diff --git a/drivers/char/hw_random/airoha-trng.c b/drivers/char/hw_random/airoha-trng.c
> index 1dbfa9505c21..3e94233e1389 100644
> --- a/drivers/char/hw_random/airoha-trng.c
> +++ b/drivers/char/hw_random/airoha-trng.c
> @@ -76,7 +76,7 @@ static int airoha_trng_irq_unmask(struct airoha_trng *trng)
>  static int airoha_trng_init(struct hwrng *rng)
>  {
>  	struct airoha_trng *trng = container_of(rng, struct airoha_trng, rng);
> -	int ret;
> +	unsigned long ret;
>  	u32 val;

>  	val = readl(trng->base + TRNG_NS_SEK_AND_DAT_EN);
> @@ -88,7 +88,7 @@ static int airoha_trng_init(struct hwrng *rng)
>  	writel(0, trng->base + TRNG_HEALTH_TEST_SW_RST);

>  	ret = wait_for_completion_timeout(&trng->rng_op_done, BUSY_LOOP_TIMEOUT);
> -	if (ret <= 0) {
> +	if (ret == 0) {
>  		dev_err(trng->dev, "Timeout waiting for Health Check\n");
>  		airoha_trng_irq_mask(trng);
>  		return -ENODEV;
> -- 
> 2.50.1.windows.1

Reviewed-by: Martin Kaiser <martin@kaiser.cx>

Patchew 2.1-devel-b67e4c2

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