On Sat, Jan 28, 2023 at 05:03:02PM +1100, Frank Crawford wrote:
> Disabling configuration mode on some chips can result in system
> hang-ups and access failures to the Super-IO chip at the
> second SIO address. Never exit configuration mode on these
> chips to avoid the problem.
>
> This patch should be applied in conjunction with a previous one to
> initialise the second chip for certain mother boards.
>
> Signed-off-by: Frank Crawford <frank@xxxxxxxxxxxxxxxxxx>
> ---
>
> v3:
> * Correct possible uninitialised pointer issue.
>
> v2:
> * Convert to use feature flag and related macros rather than a separate
> field, as suggested in review.
> * Reverse sense of flag in superio_exit to simplify feature macro.
>
> ---
> drivers/hwmon/it87.c | 26 ++++++++++++++++++--------
> 1 file changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
> index a8a6a0ffee82..923a9563be92 100644
> --- a/drivers/hwmon/it87.c
> +++ b/drivers/hwmon/it87.c
> @@ -128,10 +128,12 @@ static inline int superio_enter(int ioreg)
> return 0;
> }
>
> -static inline void superio_exit(int ioreg)
> +static inline void superio_exit(int ioreg, bool noexit)
> {
> - outb(0x02, ioreg);
> - outb(0x02, ioreg + 1);
> + if (!noexit) {
> + outb(0x02, ioreg);
> + outb(0x02, ioreg + 1);
> + }
> release_region(ioreg, 2);
> }
>
> @@ -300,6 +302,13 @@ struct it87_devices {
> #define FEAT_PWM_FREQ2 BIT(16) /* Separate pwm freq 2 */
> #define FEAT_SIX_TEMP BIT(17) /* Up to 6 temp sensors */
> #define FEAT_VIN3_5V BIT(18) /* VIN3 connected to +5V */
> +/*
> + * Disabling configuration mode on some chips can result in system
> + * hang-ups and access failures to the Super-IO chip at the
> + * second SIO address. Never exit configuration mode on these
> + * chips to avoid the problem.
> + */
> +#define FEAT_CONF_NOEXIT BIT(28) /* Chip should not exit conf mode */
Feature bits are supposed to be numbered sequentially, not randomly
assigned. Please use bit 19.
>
> static const struct it87_devices it87_devices[] = {
> [it87] = {
> @@ -493,6 +502,7 @@ static const struct it87_devices it87_devices[] = {
> #define has_pwm_freq2(data) ((data)->features & FEAT_PWM_FREQ2)
> #define has_six_temp(data) ((data)->features & FEAT_SIX_TEMP)
> #define has_vin3_5v(data) ((data)->features & FEAT_VIN3_5V)
> +#define has_conf_noexit(data) ((data)->features & FEAT_CONF_NOEXIT)
>
> struct it87_sio_data {
> int sioaddr;
> @@ -2404,7 +2414,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
> {
> int err;
> u16 chip_type;
> - const struct it87_devices *config;
> + const struct it87_devices *config = NULL;
>
> err = superio_enter(sioaddr);
> if (err)
> @@ -2489,6 +2499,8 @@ static int __init it87_find(int sioaddr, unsigned short *address,
> goto exit;
> }
>
> + config = &it87_devices[sio_data->type];
> +
> superio_select(sioaddr, PME);
> if (!(superio_inb(sioaddr, IT87_ACT_REG) & 0x01)) {
> pr_info("Device not activated, skipping\n");
> @@ -2508,8 +2520,6 @@ static int __init it87_find(int sioaddr, unsigned short *address,
> it87_devices[sio_data->type].suffix,
> *address, sio_data->revision);
>
> - config = &it87_devices[sio_data->type];
> -
> /* in7 (VSB or VCCH5V) is always internal on some chips */
> if (has_in7_internal(config))
> sio_data->internal |= BIT(1);
> @@ -2827,7 +2837,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
> sio_data->skip_pwm |= dmi_data->skip_pwm;
>
> exit:
> - superio_exit(sioaddr);
> + superio_exit(sioaddr, config ? has_conf_noexit(config) : false);
Nit: "config && has_conf_noexit(config)" would avoid the conditional code.
> return err;
> }
>
> @@ -3213,7 +3223,7 @@ static void it87_resume_sio(struct platform_device *pdev)
> reg2c);
> }
>
> - superio_exit(data->sioaddr);
> + superio_exit(data->sioaddr, has_conf_noexit(data));
> }
>
> static int it87_resume(struct device *dev)
