Hi Alexandre,
I'm trying to figure out the best way to fix the following VLA warnings:
drivers/rtc/rtc-s5m.c:370:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
drivers/rtc/rtc-s5m.c:416:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
drivers/rtc/rtc-s5m.c:453:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
drivers/rtc/rtc-s5m.c:503:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
drivers/rtc/rtc-s5m.c:548:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
drivers/rtc/rtc-s5m.c:601:2: warning: ISO C90 forbids variable length
array ‘data’ [-Wvla]
So I took a look into the following piece of code at
drivers/rtc/rtc-s5m.c:31, please see my comments below.
/*
* Registers used by the driver which are different between chipsets.
*
* Operations like read time and write alarm/time require updating
* specific fields in UDR register. These fields usually are auto-cleared
* (with some exceptions).
*
* Table of operations per device:
*
* Device | Write time | Read time | Write alarm
* =================================================
* S5M8767 | UDR + TIME | | UDR
* S2MPS11/14 | WUDR | RUDR | WUDR + RUDR
* S2MPS13 | WUDR | RUDR | WUDR + AUDR
* S2MPS15 | WUDR | RUDR | AUDR
*/
struct s5m_rtc_reg_config {
/* Number of registers used for setting time/alarm0/alarm1 */
unsigned int regs_count;
Once the maximum number of registers for devices S5M8767, S2MPS11/14
S2MPS13 and S2MPS15 are 8, 7, 7 and 7 correspondingly, I think we can
safely change the type of regs_count to u8/uint8_t. And then define a
macro like the following:
#define MAX_NUM_REGS 8 or 10
so we can replace this kind of code:
u8 data[info->regs->regs_count];
with this:
u8 data[MAX_NUM_REGS];
What do you think?
Is there any chance a new device of this kind with more than 10 or 15
registers can be added in the future?
/* First register for time, seconds */
unsigned int time;
/* RTC control register */
unsigned int ctrl;
/* First register for alarm 0, seconds */
unsigned int alarm0;
/* First register for alarm 1, seconds */
unsigned int alarm1;
/*
* Register for update flag (UDR). Typically setting UDR field to 1
* will enable update of time or alarm register. Then it will be
* auto-cleared after successful update.
*/
unsigned int udr_update;
/* Auto-cleared mask in UDR field for writing time and alarm */
unsigned int autoclear_udr_mask;
/*
* Masks in UDR field for time and alarm operations.
* The read time mask can be 0. Rest should not.
*/
unsigned int read_time_udr_mask;
unsigned int write_time_udr_mask;
unsigned int write_alarm_udr_mask;
};
/* Register map for S5M8763 and S5M8767 */
static const struct s5m_rtc_reg_config s5m_rtc_regs = {
.regs_count = 8,
.time = S5M_RTC_SEC,
.ctrl = S5M_ALARM1_CONF,
.alarm0 = S5M_ALARM0_SEC,
.alarm1 = S5M_ALARM1_SEC,
.udr_update = S5M_RTC_UDR_CON,
.autoclear_udr_mask = S5M_RTC_UDR_MASK,
.read_time_udr_mask = 0, /* Not needed */
.write_time_udr_mask = S5M_RTC_UDR_MASK | S5M_RTC_TIME_EN_MASK,
.write_alarm_udr_mask = S5M_RTC_UDR_MASK,
};
/* Register map for S2MPS13 */
static const struct s5m_rtc_reg_config s2mps13_rtc_regs = {
.regs_count = 7,
.time = S2MPS_RTC_SEC,
.ctrl = S2MPS_RTC_CTRL,
.alarm0 = S2MPS_ALARM0_SEC,
.alarm1 = S2MPS_ALARM1_SEC,
.udr_update = S2MPS_RTC_UDR_CON,
.autoclear_udr_mask = S2MPS_RTC_WUDR_MASK,
.read_time_udr_mask = S2MPS_RTC_RUDR_MASK,
.write_time_udr_mask = S2MPS_RTC_WUDR_MASK,
.write_alarm_udr_mask = S2MPS_RTC_WUDR_MASK | S2MPS13_RTC_AUDR_MASK,
};
/* Register map for S2MPS11/14 */
static const struct s5m_rtc_reg_config s2mps14_rtc_regs = {
.regs_count = 7,
.time = S2MPS_RTC_SEC,
.ctrl = S2MPS_RTC_CTRL,
.alarm0 = S2MPS_ALARM0_SEC,
.alarm1 = S2MPS_ALARM1_SEC,
.udr_update = S2MPS_RTC_UDR_CON,
.autoclear_udr_mask = S2MPS_RTC_WUDR_MASK,
.read_time_udr_mask = S2MPS_RTC_RUDR_MASK,
.write_time_udr_mask = S2MPS_RTC_WUDR_MASK,
.write_alarm_udr_mask = S2MPS_RTC_WUDR_MASK | S2MPS_RTC_RUDR_MASK,
};
/*
* Register map for S2MPS15 - in comparison to S2MPS14 the WUDR and
AUDR bits
* are swapped.
*/
static const struct s5m_rtc_reg_config s2mps15_rtc_regs = {
.regs_count = 7,
.time = S2MPS_RTC_SEC,
.ctrl = S2MPS_RTC_CTRL,
.alarm0 = S2MPS_ALARM0_SEC,
.alarm1 = S2MPS_ALARM1_SEC,
.udr_update = S2MPS_RTC_UDR_CON,
.autoclear_udr_mask = S2MPS_RTC_WUDR_MASK,
.read_time_udr_mask = S2MPS_RTC_RUDR_MASK,
.write_time_udr_mask = S2MPS15_RTC_WUDR_MASK,
.write_alarm_udr_mask = S2MPS15_RTC_AUDR_MASK,
};
Thanks
--
Gustavo
