LinuxLists.cc - [PATCH 0/7] serial: sc16is7xx and max310x: regmap fixes and improvements

2023-11-30 19:11:10

Subject: [PATCH 0/7] serial: sc16is7xx and max310x: regmap fixes and improvements

From: Hugo Villeneuve <[email protected]>

Hello,
this patch series brings fixes and improvements related to regmap access
for sc16is7xx and max310x drivers.

They are related to commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port").

Patches 1 and 2 address some comments formulated during review of the
source patch listed above.

Patch 3 removes a structure member made obsolete.

Patches 4 and 5 are improvements for code readability.

Patches 6 and 7 port improvements from patches 4 and 5 of the sc16is7xx
driver over to the max310x driver.

I have tested the changes on a custom board with two SC16IS752 DUART over
a SPI interface using a Variscite IMX8MN NANO SOM. The four UARTs are
configured in RS-485 mode.

Thank you.

Hugo Villeneuve (7):
serial: sc16is7xx: fix snprintf format specifier in
sc16is7xx_regmap_name()
serial: sc16is7xx: remove global regmap from struct sc16is7xx_port
serial: sc16is7xx: remove unused line structure member
serial: sc16is7xx: add macro for max number of UART ports
serial: sc16is7xx: improve sc16is7xx_regmap_name() buffer size
computation
serial: max310x: add macro for max number of ports
serial: max310x: use separate regmap name for each port

drivers/tty/serial/max310x.c | 19 +++++++++++++++++--
drivers/tty/serial/sc16is7xx.c | 32 ++++++++++++++++++--------------
2 files changed, 35 insertions(+), 16 deletions(-)

base-commit: d804987153e7bedf503f8e4ba649afe52cfd7f6d
--
2.39.2

2023-11-30 19:11:13

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

From: Hugo Villeneuve <[email protected]>

Change snprint format specifier from %d to %u since port_id is unsigned.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc: [email protected] # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
Suggested-by: Andy Shevchenko <[email protected]>
Signed-off-by: Hugo Villeneuve <[email protected]>
---
I did not originally add a "Cc: stable" tag for commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
as it was intended only to improve debugging using debugfs. But
since then, I have been able to confirm that it also fixes a long standing
bug in our system where the Tx interrupt are no longer enabled at some
point when transmitting large RS-485 paquets (> 64 bytes, which is the size
of the FIFO). I have been investigating why, but so far I haven't found the
exact cause, altough I suspect it has something to do with regmap caching.
Therefore, I have added it as a prerequisite for this patch so that it is
automatically added to the stable kernels.
---
drivers/tty/serial/sc16is7xx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 10e90a7774f0..8e5baf2f6ec6 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1700,7 +1700,7 @@ static const char *sc16is7xx_regmap_name(unsigned int port_id)
{
static char buf[6];

- snprintf(buf, sizeof(buf), "port%d", port_id);
+ snprintf(buf, sizeof(buf), "port%u", port_id);

return buf;
}
--
2.39.2

2023-11-30 19:11:28

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 4/7] serial: sc16is7xx: add macro for max number of UART ports

From: Hugo Villeneuve <[email protected]>

Add macro to hold the maximum number of UART ports per IC/device.

Signed-off-by: Hugo Villeneuve <[email protected]>
---
drivers/tty/serial/sc16is7xx.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index eb2c0dcd3775..750c55b93f5e 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -28,6 +28,7 @@

#define SC16IS7XX_NAME "sc16is7xx"
#define SC16IS7XX_MAX_DEVS 8
+#define SC16IS7XX_MAX_PORTS 2 /* Maximum number of UART ports per IC. */

/* SC16IS7XX register definitions */
#define SC16IS7XX_RHR_REG (0x00) /* RX FIFO */
@@ -1399,7 +1400,7 @@ static void sc16is7xx_setup_irda_ports(struct sc16is7xx_port *s)
int i;
int ret;
int count;
- u32 irda_port[2];
+ u32 irda_port[SC16IS7XX_MAX_PORTS];
struct device *dev = s->p[0].port.dev;

count = device_property_count_u32(dev, "irda-mode-ports");
@@ -1426,7 +1427,7 @@ static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s,
int i;
int ret;
int count;
- u32 mctrl_port[2];
+ u32 mctrl_port[SC16IS7XX_MAX_PORTS];
struct device *dev = s->p[0].port.dev;

count = device_property_count_u32(dev, "nxp,modem-control-line-ports");
@@ -1716,7 +1717,7 @@ static unsigned int sc16is7xx_regmap_port_mask(unsigned int port_id)
static int sc16is7xx_spi_probe(struct spi_device *spi)
{
const struct sc16is7xx_devtype *devtype;
- struct regmap *regmaps[2];
+ struct regmap *regmaps[SC16IS7XX_MAX_PORTS];
unsigned int i;
int ret;

@@ -1791,7 +1792,7 @@ static int sc16is7xx_i2c_probe(struct i2c_client *i2c)
{
const struct i2c_device_id *id = i2c_client_get_device_id(i2c);
const struct sc16is7xx_devtype *devtype;
- struct regmap *regmaps[2];
+ struct regmap *regmaps[SC16IS7XX_MAX_PORTS];
unsigned int i;

if (i2c->dev.of_node) {
--
2.39.2

2023-11-30 19:11:32

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 5/7] serial: sc16is7xx: improve sc16is7xx_regmap_name() buffer size computation

From: Hugo Villeneuve <[email protected]>

Define macro for regmap port name suffix and use it in addition to
SC16IS7XX_MAX_PORTS to automatically compute the required buffer size to
hold the name.

This helps with code readability by making it more obvious what is the
required size of the buffer.

Signed-off-by: Hugo Villeneuve <[email protected]>
---
drivers/tty/serial/sc16is7xx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 750c55b93f5e..b02e6c79da67 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -20,6 +20,7 @@
#include <linux/regmap.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
+#include <linux/stringify.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/spi/spi.h>
@@ -27,6 +28,7 @@
#include <uapi/linux/sched/types.h>

#define SC16IS7XX_NAME "sc16is7xx"
+#define SC16IS7XX_PORT_NAME_SUFFIX "port" /* Used for regmap name. */
#define SC16IS7XX_MAX_DEVS 8
#define SC16IS7XX_MAX_PORTS 2 /* Maximum number of UART ports per IC. */

@@ -1700,9 +1702,9 @@ static struct regmap_config regcfg = {

static const char *sc16is7xx_regmap_name(unsigned int port_id)
{
- static char buf[6];
+ static char buf[sizeof(SC16IS7XX_PORT_NAME_SUFFIX __stringify(SC16IS7XX_MAX_PORTS))];

- snprintf(buf, sizeof(buf), "port%u", port_id);
+ snprintf(buf, sizeof(buf), SC16IS7XX_PORT_NAME_SUFFIX "%u", port_id);

return buf;
}
--
2.39.2

2023-11-30 19:11:33

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 3/7] serial: sc16is7xx: remove unused line structure member

From: Hugo Villeneuve <[email protected]>

Now that the driver has been converted to use one regmap per port, the line
structure member is no longer used, so remove it.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc: [email protected]
Signed-off-by: Hugo Villeneuve <[email protected]>
---
drivers/tty/serial/sc16is7xx.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 23dbf77633aa..eb2c0dcd3775 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -322,7 +322,6 @@ struct sc16is7xx_one_config {

struct sc16is7xx_one {
struct uart_port port;
- u8 line;
struct regmap *regmap;
struct kthread_work tx_work;
struct kthread_work reg_work;
@@ -1540,7 +1539,6 @@ static int sc16is7xx_probe(struct device *dev,
SC16IS7XX_IOCONTROL_SRESET_BIT);

for (i = 0; i < devtype->nr_uart; ++i) {
- s->p[i].line = i;
/* Initialize port data */
s->p[i].port.dev = dev;
s->p[i].port.irq = irq;
--
2.39.2

2023-11-30 19:11:36

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 7/7] serial: max310x: use separate regmap name for each port

From: Hugo Villeneuve <[email protected]>

Use a separate regmap name for each port so that each port can have its own
debugfs entry, allowing to access each port registers independently.

For example, a four channels/ports device like the MAX14830 will have four
entries in its regmap debugfs:

$ find /sys/kernel/debug/regmap -type d | grep spi0.0
/sys/kernel/debug/regmap/spi0.0-port0
/sys/kernel/debug/regmap/spi0.0-port1
/sys/kernel/debug/regmap/spi0.0-port2
/sys/kernel/debug/regmap/spi0.0-port3

Signed-off-by: Hugo Villeneuve <[email protected]>
---
drivers/tty/serial/max310x.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 58dd5cc62014..d2eca05a6966 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -27,6 +27,7 @@
#include <linux/uaccess.h>

#define MAX310X_NAME "max310x"
+#define MAX310X_PORT_NAME_SUFFIX "port"
#define MAX310X_MAJOR 204
#define MAX310X_MINOR 209
#define MAX310X_UART_NRMAX 16
@@ -1486,6 +1487,15 @@ static struct regmap_config regcfg = {
.max_raw_write = MAX310X_FIFO_SIZE,
};

+static const char *max310x_regmap_name(unsigned int port_id)
+{
+ static char buf[sizeof(MAX310X_PORT_NAME_SUFFIX __stringify(MAX310X_MAX_PORTS))];
+
+ snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
+
+ return buf;
+}
+
#ifdef CONFIG_SPI_MASTER
static int max310x_spi_extended_reg_enable(struct device *dev, bool enable)
{
@@ -1521,6 +1531,8 @@ static int max310x_spi_probe(struct spi_device *spi)

for (i = 0; i < devtype->nr; i++) {
u8 port_mask = i * 0x20;
+
+ regcfg.name = max310x_regmap_name(i);
regcfg.read_flag_mask = port_mask;
regcfg.write_flag_mask = port_mask | MAX310X_WRITE_BIT;
regmaps[i] = devm_regmap_init_spi(spi, &regcfg);
@@ -1617,6 +1629,7 @@ static int max310x_i2c_probe(struct i2c_client *client)
client->addr, devtype->slave_addr.min,
devtype->slave_addr.max);

+ regcfg_i2c.name = max310x_regmap_name(0);
regmaps[0] = devm_regmap_init_i2c(client, &regcfg_i2c);

for (i = 1; i < devtype->nr; i++) {
@@ -1625,6 +1638,7 @@ static int max310x_i2c_probe(struct i2c_client *client)
client->adapter,
port_addr);

+ regcfg_i2c.name = max310x_regmap_name(i);
regmaps[i] = devm_regmap_init_i2c(port_client, &regcfg_i2c);
}

--
2.39.2

2023-11-30 19:11:40

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 6/7] serial: max310x: add macro for max number of ports

2023-11-30 19:11:42

by Hugo Villeneuve

[permalink] [raw]

Subject: [PATCH 2/7] serial: sc16is7xx: remove global regmap from struct sc16is7xx_port

From: Hugo Villeneuve <[email protected]>

Remove global struct regmap so that it is more obvious that this
regmap is to be used only in the probe function.

Also add a comment to that effect in probe function.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc: [email protected]
Suggested-by: Andy Shevchenko <[email protected]>
Signed-off-by: Hugo Villeneuve <[email protected]>
---
drivers/tty/serial/sc16is7xx.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 8e5baf2f6ec6..23dbf77633aa 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -334,7 +334,6 @@ struct sc16is7xx_one {

struct sc16is7xx_port {
const struct sc16is7xx_devtype *devtype;
- struct regmap *regmap;
struct clk *clk;
#ifdef CONFIG_GPIOLIB
struct gpio_chip gpio;
@@ -1422,7 +1421,8 @@ static void sc16is7xx_setup_irda_ports(struct sc16is7xx_port *s)
/*
* Configure ports designated to operate as modem control lines.
*/
-static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s)
+static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s,
+ struct regmap *regmap)
{
int i;
int ret;
@@ -1451,7 +1451,7 @@ static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s)

if (s->mctrl_mask)
regmap_update_bits(
- s->regmap,
+ regmap,
SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_MODEM_A_BIT |
SC16IS7XX_IOCONTROL_MODEM_B_BIT, s->mctrl_mask);
@@ -1483,6 +1483,10 @@ static int sc16is7xx_probe(struct device *dev,
* This device does not have an identification register that would
* tell us if we are really connected to the correct device.
* The best we can do is to check if communication is at all possible.
+ *
+ * Note: regmap[0] is used in the probe function to access registers
+ * common to all channels/ports, as it is guaranteed to be present on
+ * all variants.
*/
ret = regmap_read(regmaps[0], SC16IS7XX_LSR_REG, &val);
if (ret < 0)
@@ -1518,7 +1522,6 @@ static int sc16is7xx_probe(struct device *dev,
return -EINVAL;
}

- s->regmap = regmaps[0];
s->devtype = devtype;
dev_set_drvdata(dev, s);
mutex_init(&s->efr_lock);
@@ -1533,7 +1536,7 @@ static int sc16is7xx_probe(struct device *dev,
sched_set_fifo(s->kworker_task);

/* reset device, purging any pending irq / data */
- regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG,
+ regmap_write(regmaps[0], SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_SRESET_BIT);

for (i = 0; i < devtype->nr_uart; ++i) {
@@ -1604,7 +1607,7 @@ static int sc16is7xx_probe(struct device *dev,

sc16is7xx_setup_irda_ports(s);

- ret = sc16is7xx_setup_mctrl_ports(s);
+ ret = sc16is7xx_setup_mctrl_ports(s, regmaps[0]);
if (ret)
goto out_ports;

--
2.39.2

2023-12-01 15:59:32

by Jan Kundrát

[permalink] [raw]

Subject: Re: [PATCH 6/7] serial: max310x: add macro for max number of ports

On čtvrtek 30. listopadu 2023 20:10:48 CET, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <[email protected]>
>
> Add macro to hold the maximum number of UART ports per IC/device.
>
> Signed-off-by: Hugo Villeneuve <[email protected]>

Reviewed-by: Jan Kundrát <[email protected]>
Tested-by: Jan Kundrát <[email protected]>

> ---
> drivers/tty/serial/max310x.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
> index f3a99daebdaa..58dd5cc62014 100644
> --- a/drivers/tty/serial/max310x.c
> +++ b/drivers/tty/serial/max310x.c
> @@ -30,6 +30,7 @@
> #define MAX310X_MAJOR 204
> #define MAX310X_MINOR 209
> #define MAX310X_UART_NRMAX 16
> +#define MAX310X_MAX_PORTS 4 /* Maximum number of UART ports per IC. */
>
> /* MAX310X register definitions */
> #define MAX310X_RHR_REG (0x00) /* RX FIFO */
> @@ -1502,7 +1503,7 @@ static const struct max310x_if_cfg
> __maybe_unused max310x_spi_if_cfg = {
> static int max310x_spi_probe(struct spi_device *spi)
> {
> const struct max310x_devtype *devtype;
> - struct regmap *regmaps[4];
> + struct regmap *regmaps[MAX310X_MAX_PORTS];
> unsigned int i;
> int ret;
>
> @@ -1605,7 +1606,7 @@ static int max310x_i2c_probe(struct
> i2c_client *client)
> const struct max310x_devtype *devtype =
> device_get_match_data(&client->dev);
> struct i2c_client *port_client;
> - struct regmap *regmaps[4];
> + struct regmap *regmaps[MAX310X_MAX_PORTS];
> unsigned int i;
> u8 port_addr;
>

2023-12-01 16:01:04

by Jan Kundrát

[permalink] [raw]

Subject: Re: [PATCH 7/7] serial: max310x: use separate regmap name for each port

On čtvrtek 30. listopadu 2023 20:10:49 CET, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <[email protected]>
>
> Use a separate regmap name for each port so that each port can have its own
> debugfs entry, allowing to access each port registers independently.
>
> For example, a four channels/ports device like the MAX14830 will have four
> entries in its regmap debugfs:
>
> $ find /sys/kernel/debug/regmap -type d | grep spi0.0
> /sys/kernel/debug/regmap/spi0.0-port0
> /sys/kernel/debug/regmap/spi0.0-port1
> /sys/kernel/debug/regmap/spi0.0-port2
> /sys/kernel/debug/regmap/spi0.0-port3
>
> Signed-off-by: Hugo Villeneuve <[email protected]>

I was carrying a similar patch locally, and this one works for me as well.

Reviewed-by: Jan Kundrát <[email protected]>
Tested-by: Jan Kundrát <[email protected]>

> ---
> drivers/tty/serial/max310x.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
> index 58dd5cc62014..d2eca05a6966 100644
> --- a/drivers/tty/serial/max310x.c
> +++ b/drivers/tty/serial/max310x.c
> @@ -27,6 +27,7 @@
> #include <linux/uaccess.h>
>
> #define MAX310X_NAME "max310x"
> +#define MAX310X_PORT_NAME_SUFFIX "port"
> #define MAX310X_MAJOR 204
> #define MAX310X_MINOR 209
> #define MAX310X_UART_NRMAX 16
> @@ -1486,6 +1487,15 @@ static struct regmap_config regcfg = {
> .max_raw_write = MAX310X_FIFO_SIZE,
> };
>
> +static const char *max310x_regmap_name(unsigned int port_id)
> +{
> + static char buf[sizeof(MAX310X_PORT_NAME_SUFFIX
> __stringify(MAX310X_MAX_PORTS))];
> +
> + snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
> +
> + return buf;
> +}
> +
> #ifdef CONFIG_SPI_MASTER
> static int max310x_spi_extended_reg_enable(struct device *dev, bool enable)
> {
> @@ -1521,6 +1531,8 @@ static int max310x_spi_probe(struct spi_device *spi)
>
> for (i = 0; i < devtype->nr; i++) {
> u8 port_mask = i * 0x20;
> +
> + regcfg.name = max310x_regmap_name(i);
> regcfg.read_flag_mask = port_mask;
> regcfg.write_flag_mask = port_mask | MAX310X_WRITE_BIT;
> regmaps[i] = devm_regmap_init_spi(spi, &regcfg);
> @@ -1617,6 +1629,7 @@ static int max310x_i2c_probe(struct
> i2c_client *client)
> client->addr, devtype->slave_addr.min,
> devtype->slave_addr.max);
>
> + regcfg_i2c.name = max310x_regmap_name(0);
> regmaps[0] = devm_regmap_init_i2c(client, &regcfg_i2c);
>
> for (i = 1; i < devtype->nr; i++) {
> @@ -1625,6 +1638,7 @@ static int max310x_i2c_probe(struct
> i2c_client *client)
> client->adapter,
> port_addr);
>
> + regcfg_i2c.name = max310x_regmap_name(i);
> regmaps[i] = devm_regmap_init_i2c(port_client, &regcfg_i2c);
> }
>

2023-12-06 06:32:03

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

2023-12-06 14:24:04

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH 7/7] serial: max310x: use separate regmap name for each port

Hi Hugo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on d804987153e7bedf503f8e4ba649afe52cfd7f6d]

url: https://github.com/intel-lab-lkp/linux/commits/Hugo-Villeneuve/serial-sc16is7xx-fix-snprintf-format-specifier-in-sc16is7xx_regmap_name/20231201-031413
base: d804987153e7bedf503f8e4ba649afe52cfd7f6d
patch link: https://lore.kernel.org/r/20231130191050.3165862-8-hugo%40hugovil.com
patch subject: [PATCH 7/7] serial: max310x: use separate regmap name for each port
config: arm-randconfig-r081-20231201 (https://download.01.org/0day-ci/archive/20231206/[email protected]/config)
compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231206/[email protected]/reproduce)

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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All warnings (new ones prefixed by >>):

In function 'max310x_regmap_name',
inlined from 'max310x_i2c_probe' at drivers/tty/serial/max310x.c:1641:21:
>> drivers/tty/serial/max310x.c:30:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
30 | #define MAX310X_PORT_NAME_SUFFIX "port"
| ^~~~~~
drivers/tty/serial/max310x.c:1494:36: note: in expansion of macro 'MAX310X_PORT_NAME_SUFFIX'
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/max310x.c: In function 'max310x_i2c_probe':
drivers/tty/serial/max310x.c:1494:62: note: format string is defined here
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~
In function 'max310x_regmap_name',
inlined from 'max310x_i2c_probe' at drivers/tty/serial/max310x.c:1641:21:
drivers/tty/serial/max310x.c:30:41: note: directive argument in the range [1, 4294967294]
30 | #define MAX310X_PORT_NAME_SUFFIX "port"
| ^~~~~~
drivers/tty/serial/max310x.c:1494:36: note: in expansion of macro 'MAX310X_PORT_NAME_SUFFIX'
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/max310x.c:1494:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'max310x_regmap_name',
inlined from 'max310x_spi_probe' at drivers/tty/serial/max310x.c:1535:17:
>> drivers/tty/serial/max310x.c:30:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
30 | #define MAX310X_PORT_NAME_SUFFIX "port"
| ^~~~~~
drivers/tty/serial/max310x.c:1494:36: note: in expansion of macro 'MAX310X_PORT_NAME_SUFFIX'
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/max310x.c: In function 'max310x_spi_probe':
drivers/tty/serial/max310x.c:1494:62: note: format string is defined here
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~
In function 'max310x_regmap_name',
inlined from 'max310x_spi_probe' at drivers/tty/serial/max310x.c:1535:17:
drivers/tty/serial/max310x.c:30:41: note: directive argument in the range [0, 4294967294]
30 | #define MAX310X_PORT_NAME_SUFFIX "port"
| ^~~~~~
drivers/tty/serial/max310x.c:1494:36: note: in expansion of macro 'MAX310X_PORT_NAME_SUFFIX'
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/max310x.c:1494:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
1494 | snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

vim +30 drivers/tty/serial/max310x.c

28
29 #define MAX310X_NAME "max310x"
> 30 #define MAX310X_PORT_NAME_SUFFIX "port"
31 #define MAX310X_MAJOR 204
32 #define MAX310X_MINOR 209
33 #define MAX310X_UART_NRMAX 16
34 #define MAX310X_MAX_PORTS 4 /* Maximum number of UART ports per IC. */
35

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

2023-12-07 06:51:40

by Greg Kroah-Hartman

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, Nov 30, 2023 at 02:10:43PM -0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <[email protected]>
>
> Change snprint format specifier from %d to %u since port_id is unsigned.
>
> Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> Cc: [email protected] # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
> Suggested-by: Andy Shevchenko <[email protected]>
> Signed-off-by: Hugo Villeneuve <[email protected]>
> ---
> I did not originally add a "Cc: stable" tag for commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> as it was intended only to improve debugging using debugfs. But
> since then, I have been able to confirm that it also fixes a long standing
> bug in our system where the Tx interrupt are no longer enabled at some
> point when transmitting large RS-485 paquets (> 64 bytes, which is the size
> of the FIFO). I have been investigating why, but so far I haven't found the
> exact cause, altough I suspect it has something to do with regmap caching.
> Therefore, I have added it as a prerequisite for this patch so that it is
> automatically added to the stable kernels.

Looks like the 0-day test bot found problems with this, so I'll hold off
on taking this patch and the rest of the series until that's fixed up
with a new version of this series.

thanks,

greg k-h

2023-12-07 06:51:51

by Greg Kroah-Hartman

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, Nov 30, 2023 at 02:10:43PM -0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <[email protected]>
>
> Change snprint format specifier from %d to %u since port_id is unsigned.
>
> Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> Cc: [email protected] # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
> Suggested-by: Andy Shevchenko <[email protected]>
> Signed-off-by: Hugo Villeneuve <[email protected]>
> ---
> I did not originally add a "Cc: stable" tag for commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> as it was intended only to improve debugging using debugfs. But
> since then, I have been able to confirm that it also fixes a long standing
> bug in our system where the Tx interrupt are no longer enabled at some
> point when transmitting large RS-485 paquets (> 64 bytes, which is the size
> of the FIFO). I have been investigating why, but so far I haven't found the
> exact cause, altough I suspect it has something to do with regmap caching.
> Therefore, I have added it as a prerequisite for this patch so that it is
> automatically added to the stable kernels.

As you are splitting fixes from non-fixes in this series, please resend
this as 2 different series, one that I can apply now to my tty-linus
branch to get merged for 6.7-final, and one that can go into tty-next
for 6.8-rc1. Mixing them up here just ensures that they all would get
applied to tty-next.

thanks,

greg k-h

2023-12-07 16:03:19

by Hugo Villeneuve

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, 7 Dec 2023 10:44:33 +0900
Greg KH <[email protected]> wrote:

> On Thu, Nov 30, 2023 at 02:10:43PM -0500, Hugo Villeneuve wrote:
> > From: Hugo Villeneuve <[email protected]>
> >
> > Change snprint format specifier from %d to %u since port_id is unsigned.
> >
> > Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> > Cc: [email protected] # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
> > Suggested-by: Andy Shevchenko <[email protected]>
> > Signed-off-by: Hugo Villeneuve <[email protected]>
> > ---
> > I did not originally add a "Cc: stable" tag for commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> > as it was intended only to improve debugging using debugfs. But
> > since then, I have been able to confirm that it also fixes a long standing
> > bug in our system where the Tx interrupt are no longer enabled at some
> > point when transmitting large RS-485 paquets (> 64 bytes, which is the size
> > of the FIFO). I have been investigating why, but so far I haven't found the
> > exact cause, altough I suspect it has something to do with regmap caching.
> > Therefore, I have added it as a prerequisite for this patch so that it is
> > automatically added to the stable kernels.
>
> Looks like the 0-day test bot found problems with this, so I'll hold off
> on taking this patch and the rest of the series until that's fixed up
> with a new version of this series.

No problem, I am on it.

Hugo

2023-12-07 16:06:10

by Hugo Villeneuve

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, 7 Dec 2023 10:45:48 +0900
Greg KH <[email protected]> wrote:

> On Thu, Nov 30, 2023 at 02:10:43PM -0500, Hugo Villeneuve wrote:
> > From: Hugo Villeneuve <[email protected]>
> >
> > Change snprint format specifier from %d to %u since port_id is unsigned.
> >
> > Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> > Cc: [email protected] # 6.1.x: 3837a03 serial: sc16is7xx: improve regmap debugfs by using one regmap per port
> > Suggested-by: Andy Shevchenko <[email protected]>
> > Signed-off-by: Hugo Villeneuve <[email protected]>
> > ---
> > I did not originally add a "Cc: stable" tag for commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
> > as it was intended only to improve debugging using debugfs. But
> > since then, I have been able to confirm that it also fixes a long standing
> > bug in our system where the Tx interrupt are no longer enabled at some
> > point when transmitting large RS-485 paquets (> 64 bytes, which is the size
> > of the FIFO). I have been investigating why, but so far I haven't found the
> > exact cause, altough I suspect it has something to do with regmap caching.
> > Therefore, I have added it as a prerequisite for this patch so that it is
> > automatically added to the stable kernels.
>
> As you are splitting fixes from non-fixes in this series, please resend
> this as 2 different series, one that I can apply now to my tty-linus
> branch to get merged for 6.7-final, and one that can go into tty-next
> for 6.8-rc1. Mixing them up here just ensures that they all would get
> applied to tty-next.

Ok, makes sense. Will do after I fix the 0-day issue.

Thank you,
Hugo.

2023-12-07 17:53:11

by Hugo Villeneuve

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Wed, 6 Dec 2023 14:29:39 +0800
kernel test robot <[email protected]> wrote:

> Hi Hugo,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on d804987153e7bedf503f8e4ba649afe52cfd7f6d]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Hugo-Villeneuve/serial-sc16is7xx-fix-snprintf-format-specifier-in-sc16is7xx_regmap_name/20231201-031413
> base: d804987153e7bedf503f8e4ba649afe52cfd7f6d
> patch link: https://lore.kernel.org/r/20231130191050.3165862-2-hugo%40hugovil.com
> patch subject: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()
> config: x86_64-buildonly-randconfig-001-20231201 (https://download.01.org/0day-ci/archive/20231206/[email protected]/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231206/[email protected]/reproduce)
>
> 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 <[email protected]>
> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
>
> All warnings (new ones prefixed by >>):
>
> drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe':
> >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
> 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> | ^~
> In function 'sc16is7xx_regmap_name',
> inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7xx.c:1805:17:
> drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in the range [0, 4294967294]
> 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> | ^~~~~~~~
> drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
> 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Hi,
the only solution I could find is to add this line just before snprintf:

BUG_ON(port_id > MAX310X_MAX_PORTS);

it allows us to have the smallest buffer size possible.

One other solution would be to change port_id from "unsigned int"
to "u8", and increase the buffer by an additional 2 bytes to silence
the warning, but then wasting 2 bytes for each channel, like so:

static const char *max310x_regmap_name(u8 port_id)
{
static char buf[
sizeof(MAX310X_PORT_NAME_SUFFIX __stringify(UCHAR_MAX))];

I prefer solution 1, unless there is another solution that I am
unaware of.

Hugo.

> vim +1703 drivers/tty/serial/sc16is7xx.c
>
> 1698
> 1699 static const char *sc16is7xx_regmap_name(unsigned int port_id)
> 1700 {
> 1701 static char buf[6];
> 1702
> > 1703 snprintf(buf, sizeof(buf), "port%u", port_id);
> 1704
> 1705 return buf;
> 1706 }
> 1707
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>

--
Hugo Villeneuve

2023-12-07 18:25:32

by Andy Shevchenko

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, Dec 7, 2023 at 7:52 PM Hugo Villeneuve <[email protected]> wrote:
> On Wed, 6 Dec 2023 14:29:39 +0800
> kernel test robot <[email protected]> wrote:

...

> > drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe':
> > >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~
> > In function 'sc16is7xx_regmap_name',
> > inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7xx.c:1805:17:
> > drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in the range [0, 4294967294]
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~~~~~~~
> > drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Hi,
> the only solution I could find is to add this line just before snprintf:
>
> BUG_ON(port_id > MAX310X_MAX_PORTS);
>
> it allows us to have the smallest buffer size possible.
>
> One other solution would be to change port_id from "unsigned int"
> to "u8", and increase the buffer by an additional 2 bytes to silence
> the warning, but then wasting 2 bytes for each channel, like so:

I didn't get this. It's a buffer that is rewritten on each port (why
is it even static?). Just make sure it's enough for any given number
and drop the static.

...

While at it, can you look at the following items to improve?
- sc16is7xx_alloc_line() can be updated to use IDA framework
- move return xxx; to the default cases in a few functions
- if (div > 0xffff) { --> if (div >= BIT(16)) { as it better shows why
the limit is that (we have only 16 bits for the divider)
- do {} while (0) in the sc16is7xx_port_irq, WTH?!
- while (1) { -- do { } while (keep_polling); in sc16is7xx_irq()
- use in_range() in sc16is7xx_setup_mctrl_ports() ? (maybe not, dunno)
- for (i--; i >= 0; i--) { --> while (i--) {
- use spi_get_device_match_data() and i2c_get_match_data()
- 15000000 --> 15 * HZ_PER_MHZ ?
- dropping MODULE_ALIAS (and fix the ID tables, _if_ needed)
- split the code to the core / main + SPI + I2C glue drivers

* These just come on the first glance at the code, perhaps there is
more room to improve.

--
With Best Regards,
Andy Shevchenko

2023-12-07 19:02:55

by Hugo Villeneuve

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, 7 Dec 2023 20:24:45 +0200
Andy Shevchenko <[email protected]> wrote:

> On Thu, Dec 7, 2023 at 7:52 PM Hugo Villeneuve <[email protected]> wrote:
> > On Wed, 6 Dec 2023 14:29:39 +0800
> > kernel test robot <[email protected]> wrote:
>
> ...
>
> > > drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe':
> > > >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~
> > > In function 'sc16is7xx_regmap_name',
> > > inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7xx.c:1805:17:
> > > drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in the range [0, 4294967294]
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~~~~~~~
> > > drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Hi,
> > the only solution I could find is to add this line just before snprintf:
> >
> > BUG_ON(port_id > MAX310X_MAX_PORTS);
> >
> > it allows us to have the smallest buffer size possible.
> >
> > One other solution would be to change port_id from "unsigned int"
> > to "u8", and increase the buffer by an additional 2 bytes to silence
> > the warning, but then wasting 2 bytes for each channel, like so:
>
> I didn't get this. It's a buffer that is rewritten on each port (why
> is it even static?). Just make sure it's enough for any given number
> and drop the static.

Yes, using static is not appropriate, as regmap will copy each name
into its internal buffer.

I will drop the static and refactor the code accordingly.

> While at it, can you look at the following items to improve?
> - sc16is7xx_alloc_line() can be updated to use IDA framework
> - move return xxx; to the default cases in a few functions
> - if (div > 0xffff) { --> if (div >= BIT(16)) { as it better shows why
> the limit is that (we have only 16 bits for the divider)
> - do {} while (0) in the sc16is7xx_port_irq, WTH?!
> - while (1) { -- do { } while (keep_polling); in sc16is7xx_irq()
> - use in_range() in sc16is7xx_setup_mctrl_ports() ? (maybe not, dunno)
> - for (i--; i >= 0; i--) { --> while (i--) {
> - use spi_get_device_match_data() and i2c_get_match_data()
> - 15000000 --> 15 * HZ_PER_MHZ ?
> - dropping MODULE_ALIAS (and fix the ID tables, _if_ needed)
> - split the code to the core / main + SPI + I2C glue drivers
>
> * These just come on the first glance at the code, perhaps there is
> more room to improve.

Ok, no problem, I will have a look at it.

Thank you,
Hugo Villeneuve

2023-12-07 19:46:28

by David Laight

[permalink] [raw]

Subject: RE: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

From: Hugo Villeneuve
> Sent: 07 December 2023 17:53
...
> > kernel test robot noticed the following build warnings:
> >
> > [auto build test WARNING on d804987153e7bedf503f8e4ba649afe52cfd7f6d]
> >
> > url: https://github.com/intel-lab-lkp/linux/commits/Hugo-Villeneuve/serial-sc16is7xx-fix-
> snprintf-format-specifier-in-sc16is7xx_regmap_name/20231201-031413
> > base: d804987153e7bedf503f8e4ba649afe52cfd7f6d
> > patch link: https://lore.kernel.org/r/20231130191050.3165862-2-hugo%40hugovil.com
> > patch subject: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in
> sc16is7xx_regmap_name()
> > config: x86_64-buildonly-randconfig-001-20231201 (https://download.01.org/0day-
> ci/archive/20231206/[email protected]/config)
> > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-
> ci/archive/20231206/[email protected]/reproduce)
> >
> > 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 <[email protected]>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> >
> > All warnings (new ones prefixed by >>):
> >
> > drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe':
> > >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive output may be truncated writing
> between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~
> > In function 'sc16is7xx_regmap_name',
> > inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7xx.c:1805:17:
> > drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in the range [0, 4294967294]
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~~~~~~~
> > drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output between 6 and 15 bytes into a
> destination of size 6
> > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Hi,
> the only solution I could find is to add this line just before snprintf:
>
> BUG_ON(port_id > MAX310X_MAX_PORTS);
>
> it allows us to have the smallest buffer size possible.

Or "port%c", '0' + port_id);

Or maybe:
size_t buflen = sizeof (buf);
OPTIMIZER_HIDE_VAR(buflen);
snprintf(buf, buflen, fmt, args);

See https://godbolt.org/z/Wjz3xG5c4

Maybe there should be snprintf_may_truncate() (etc) in one of the headers.

David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

2023-12-12 20:03:31

by Hugo Villeneuve

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Thu, 7 Dec 2023 20:24:45 +0200
Andy Shevchenko <[email protected]> wrote:

> On Thu, Dec 7, 2023 at 7:52 PM Hugo Villeneuve <[email protected]> wrote:
> > On Wed, 6 Dec 2023 14:29:39 +0800
> > kernel test robot <[email protected]> wrote:
>
> ...
>
> > > drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe':
> > > >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive output may be truncated writing between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=]
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~
> > > In function 'sc16is7xx_regmap_name',
> > > inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7xx.c:1805:17:
> > > drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in the range [0, 4294967294]
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~~~~~~~
> > > drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output between 6 and 15 bytes into a destination of size 6
> > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id);
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Hi,
> > the only solution I could find is to add this line just before snprintf:
> >
> > BUG_ON(port_id > MAX310X_MAX_PORTS);
> >
> > it allows us to have the smallest buffer size possible.
> >
> > One other solution would be to change port_id from "unsigned int"
> > to "u8", and increase the buffer by an additional 2 bytes to silence
> > the warning, but then wasting 2 bytes for each channel, like so:
>
> I didn't get this. It's a buffer that is rewritten on each port (why
> is it even static?). Just make sure it's enough for any given number
> and drop the static.
>
> ...
>
> While at it, can you look at the following items to improve?
> - sc16is7xx_alloc_line() can be updated to use IDA framework
> - move return xxx; to the default cases in a few functions
> - if (div > 0xffff) { --> if (div >= BIT(16)) { as it better shows why
> the limit is that (we have only 16 bits for the divider)
> - do {} while (0) in the sc16is7xx_port_irq, WTH?!
> - while (1) { -- do { } while (keep_polling); in sc16is7xx_irq()
> - use in_range() in sc16is7xx_setup_mctrl_ports() ? (maybe not, dunno)
> - for (i--; i >= 0; i--) { --> while (i--) {
> - use spi_get_device_match_data() and i2c_get_match_data()
> - 15000000 --> 15 * HZ_PER_MHZ ?
> - dropping MODULE_ALIAS (and fix the ID tables, _if_ needed)
> - split the code to the core / main + SPI + I2C glue drivers
>
> * These just come on the first glance at the code, perhaps there is
> more room to improve.

Hi Andy,
just to let you know that I have implemented almost all of the fixes /
improvements. I will submit them once V2 of this current series
lands in Greg's next tree.

However, for sc16is7xx_alloc_line(), I looked at using the IDA framework
but it doesn't seem possible because there is no IDA function
to search if a bit is set, which is a needed functionality.

Hugo Villeneuve

2023-12-13 14:45:59

by Andy Shevchenko

[permalink] [raw]

Subject: Re: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name()

On Tue, Dec 12, 2023 at 10:03 PM Hugo Villeneuve <[email protected]> wrote:
> On Thu, 7 Dec 2023 20:24:45 +0200
> Andy Shevchenko <[email protected]> wrote:
> > On Thu, Dec 7, 2023 at 7:52 PM Hugo Villeneuve <[email protected]> wrote:

...

> > While at it, can you look at the following items to improve?
> > - sc16is7xx_alloc_line() can be updated to use IDA framework
> > - move return xxx; to the default cases in a few functions
> > - if (div > 0xffff) { --> if (div >= BIT(16)) { as it better shows why
> > the limit is that (we have only 16 bits for the divider)
> > - do {} while (0) in the sc16is7xx_port_irq, WTH?!
> > - while (1) { -- do { } while (keep_polling); in sc16is7xx_irq()
> > - use in_range() in sc16is7xx_setup_mctrl_ports() ? (maybe not, dunno)
> > - for (i--; i >= 0; i--) { --> while (i--) {
> > - use spi_get_device_match_data() and i2c_get_match_data()
> > - 15000000 --> 15 * HZ_PER_MHZ ?
> > - dropping MODULE_ALIAS (and fix the ID tables, _if_ needed)
> > - split the code to the core / main + SPI + I2C glue drivers
> >
> > * These just come on the first glance at the code, perhaps there is
> > more room to improve.
>
> Hi Andy,
> just to let you know that I have implemented almost all of the fixes /
> improvements. I will submit them once V2 of this current series
> lands in Greg's next tree.

Hooray!

> However, for sc16is7xx_alloc_line(), I looked at using the IDA framework
> but it doesn't seem possible because there is no IDA function
> to search if a bit is set, which is a needed functionality.

It can be done via trying to get it, but probably it's uglier than
current behaviour. Okay, let's leave it as is for now.

--
With Best Regards,
Andy Shevchenko