Messages in this thread | | | Date | Fri, 9 Apr 2021 02:01:04 -0500 | From | Zev Weiss <> | Subject | Re: [PATCH v5 2/4] drivers/tty/serial/8250: refactor sirq and lpc address setting code |
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On Fri, Apr 09, 2021 at 12:06:16AM CDT, Andrew Jeffery wrote: > > >On Thu, 8 Apr 2021, at 10:46, Zev Weiss wrote: >> This splits dedicated aspeed_vuart_set_{sirq,lpc_address}() functions >> out of the sysfs store functions in preparation for adding DT >> properties that will be poking the same registers. While we're at it, >> these functions now provide some basic bounds-checking on their >> arguments. >> >> Signed-off-by: Zev Weiss <zev@bewilderbeest.net> >> --- >> drivers/tty/serial/8250/8250_aspeed_vuart.c | 51 ++++++++++++++------- >> 1 file changed, 35 insertions(+), 16 deletions(-) >> >> diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c >> b/drivers/tty/serial/8250/8250_aspeed_vuart.c >> index c33e02cbde93..8433f8dbb186 100644 >> --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c >> +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c >> @@ -72,22 +72,31 @@ static ssize_t lpc_address_show(struct device *dev, >> return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr); >> } >> >> +static int aspeed_vuart_set_lpc_address(struct aspeed_vuart *vuart, u32 addr) >> +{ >> + if (addr > U16_MAX) >> + return -EINVAL; >> + >> + writeb(addr >> 8, vuart->regs + ASPEED_VUART_ADDRH); >> + writeb(addr >> 0, vuart->regs + ASPEED_VUART_ADDRL); >> + >> + return 0; >> +} >> + >> static ssize_t lpc_address_store(struct device *dev, >> struct device_attribute *attr, >> const char *buf, size_t count) >> { >> struct aspeed_vuart *vuart = dev_get_drvdata(dev); >> - unsigned long val; >> + u32 val; >> int err; >> >> - err = kstrtoul(buf, 0, &val); >> + err = kstrtou32(buf, 0, &val); >> if (err) >> return err; >> >> - writeb(val >> 8, vuart->regs + ASPEED_VUART_ADDRH); >> - writeb(val >> 0, vuart->regs + ASPEED_VUART_ADDRL); >> - >> - return count; >> + err = aspeed_vuart_set_lpc_address(vuart, val); >> + return err ? : count; >> } >> >> static DEVICE_ATTR_RW(lpc_address); >> @@ -105,27 +114,37 @@ static ssize_t sirq_show(struct device *dev, >> return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg); >> } >> >> +static int aspeed_vuart_set_sirq(struct aspeed_vuart *vuart, u32 sirq) >> +{ >> + u8 reg; >> + >> + if (sirq > (ASPEED_VUART_GCRB_HOST_SIRQ_MASK >> ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT)) >> + return -EINVAL; >> + >> + sirq <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT; >> + sirq &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK; > >This might be less verbose if we reordered things a little: > >``` >sirq <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT; >if (sirq & ASPEED_VUART_GCRB_HOST_SIRQ_MASK) > return -EINVAL; >sirq &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK; >```
Hmm, that (or something similar, perhaps with a '~' on the mask in the if condition?) does seem like it'd be a nice improvement, though I suppose it'd also mean we'd fail to reject some way-out-of-range sirq values (e.g. if it had its MSB set) -- so I think I'll leave it as is, just in the name of thoroughness/paranoia?
> >But otherwise it looks okay, so > >Reviewed-by: Andrew Jeffery <andrew@aj.id.au> >
Thanks.
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