* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx
@ 2012-05-26 16:11 Roland Stigge
2012-05-27 2:32 ` Arnd Bergmann
0 siblings, 1 reply; 6+ messages in thread
From: Roland Stigge @ 2012-05-26 16:11 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
this is how the modified FIFO is handled in the repositories at
git.lpclinux.com. Is there a better way for doing this (without ifdef)? Looks
like registering additional types (like PORT_16550A) isn't encouraged. Maybe
extending of_serial.c? The latter currently doesn't handle .fifosize and
.tx_loadsz, though.
Any suggestions appreciated.
Thanks in advance,
Roland
---
drivers/tty/serial/8250/8250.c | 7 +++++++
1 file changed, 7 insertions(+)
--- linux-2.6.orig/drivers/tty/serial/8250/8250.c
+++ linux-2.6/drivers/tty/serial/8250/8250.c
@@ -158,9 +158,16 @@ static const struct serial8250_config ua
},
[PORT_16550A] = {
.name = "16550A",
+#ifdef CONFIG_ARCH_LPC32XX
+ .fifo_size = 64,
+ .tx_loadsz = 32,
+ .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
+ UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
+#else
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+#endif
.flags = UART_CAP_FIFO,
},
[PORT_CIRRUS] = {
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx 2012-05-26 16:11 [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx Roland Stigge @ 2012-05-27 2:32 ` Arnd Bergmann 2012-05-27 9:06 ` Roland Stigge 0 siblings, 1 reply; 6+ messages in thread From: Arnd Bergmann @ 2012-05-27 2:32 UTC (permalink / raw) To: linux-arm-kernel On Saturday 26 May 2012, Roland Stigge wrote: > Hi, > > this is how the modified FIFO is handled in the repositories at > git.lpclinux.com. Is there a better way for doing this (without ifdef)? Looks > like registering additional types (like PORT_16550A) isn't encouraged. Maybe > extending of_serial.c? The latter currently doesn't handle .fifosize and > .tx_loadsz, though. > > Any suggestions appreciated. We occasionally add new types, and I think that would be ok here too, if it's actually a new type. It definitely doesn't look like a 16550. I wonder if it's in fact a PORT_16654, or if we can at least pretend it's one. Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx 2012-05-27 2:32 ` Arnd Bergmann @ 2012-05-27 9:06 ` Roland Stigge 2012-05-27 10:23 ` Arnd Bergmann 0 siblings, 1 reply; 6+ messages in thread From: Roland Stigge @ 2012-05-27 9:06 UTC (permalink / raw) To: linux-arm-kernel Hi, On 27/05/12 04:32, Arnd Bergmann wrote: >> this is how the modified FIFO is handled in the repositories at >> git.lpclinux.com. Is there a better way for doing this (without ifdef)? Looks >> like registering additional types (like PORT_16550A) isn't encouraged. Maybe >> extending of_serial.c? The latter currently doesn't handle .fifosize and >> .tx_loadsz, though. >> >> Any suggestions appreciated. > > We occasionally add new types, and I think that would be ok here too, if it's > actually a new type. It definitely doesn't look like a 16550. > > I wonder if it's in fact a PORT_16654, or if we can at least pretend it's one. Thanks for the hint! I did it via the following modification in of_serial.c: --- a/drivers/tty/serial/of_serial.c +++ b/drivers/tty/serial/of_serial.c @@ -179,6 +179,7 @@ static struct of_device_id __devinitdata of_platform_serial_table[] = { { .compatible = "ns16450", .data = (void *)PORT_16450, }, { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, { .compatible = "ns16550", .data = (void *)PORT_16550, }, + { .compatible = "ns16654", .data = (void *)PORT_16654, }, { .compatible = "ns16750", .data = (void *)PORT_16750, }, { .compatible = "ns16850", .data = (void *)PORT_16850, }, { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, }, Works for now, will need to test more thoroughly with LPC32xx (note that the manual explicitly mentions "downwards compatible with the INS16Cx50" and "Register locations conform to ?550 industry standard" but nothing about an EFR register which 16654 is configured for in 8250.c). The patch should be useful in of_serial anyway (even without the LPC32xx case). Wondering if it should rather be .compatible = "st16654"? Will prepare a patch with adjustment of Documentation/.../of-serial.txt when we agree on sth. Thanks, Roland ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx 2012-05-27 9:06 ` Roland Stigge @ 2012-05-27 10:23 ` Arnd Bergmann 2012-05-27 11:37 ` Roland Stigge 0 siblings, 1 reply; 6+ messages in thread From: Arnd Bergmann @ 2012-05-27 10:23 UTC (permalink / raw) To: linux-arm-kernel On Sunday 27 May 2012, Roland Stigge wrote: > I did it via the following modification in of_serial.c: > > --- a/drivers/tty/serial/of_serial.c > +++ b/drivers/tty/serial/of_serial.c > @@ -179,6 +179,7 @@ static struct of_device_id __devinitdata of_platform_serial_table[] = { > { .compatible = "ns16450", .data = (void *)PORT_16450, }, > { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, > { .compatible = "ns16550", .data = (void *)PORT_16550, }, > + { .compatible = "ns16654", .data = (void *)PORT_16654, }, > { .compatible = "ns16750", .data = (void *)PORT_16750, }, > { .compatible = "ns16850", .data = (void *)PORT_16850, }, > { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, }, > > Works for now, will need to test more thoroughly with LPC32xx (note that > the manual explicitly mentions "downwards compatible with the INS16Cx50" > and "Register locations conform to ?550 industry standard" but nothing > about an EFR register which 16654 is configured for in 8250.c). > > The patch should be useful in of_serial anyway (even without the LPC32xx > case). > > Wondering if it should rather be .compatible = "st16654"? > Will prepare a patch with adjustment of Documentation/.../of-serial.txt when > we agree on sth. I think st16654 would be better than ns16654 here, yes. Actually some of the other entries are wrong, too. The ns8250 entry should be i8250, and I guess the 16750 and 16850 were also not made by national. Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx 2012-05-27 10:23 ` Arnd Bergmann @ 2012-05-27 11:37 ` Roland Stigge 2012-05-27 12:07 ` Arnd Bergmann 0 siblings, 1 reply; 6+ messages in thread From: Roland Stigge @ 2012-05-27 11:37 UTC (permalink / raw) To: linux-arm-kernel Hi, On 27/05/12 12:23, Arnd Bergmann wrote: >> --- a/drivers/tty/serial/of_serial.c >> +++ b/drivers/tty/serial/of_serial.c >> @@ -179,6 +179,7 @@ static struct of_device_id __devinitdata of_platform_serial_table[] = { >> { .compatible = "ns16450", .data = (void *)PORT_16450, }, >> { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, >> { .compatible = "ns16550", .data = (void *)PORT_16550, }, >> + { .compatible = "ns16654", .data = (void *)PORT_16654, }, >> { .compatible = "ns16750", .data = (void *)PORT_16750, }, >> { .compatible = "ns16850", .data = (void *)PORT_16850, }, >> { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, }, >> >> Wondering if it should rather be .compatible = "st16654"? >> Will prepare a patch with adjustment of Documentation/.../of-serial.txt when >> we agree on sth. > > I think st16654 would be better than ns16654 here, yes. OK, will provide a patch accordingly. > Actually some of the other entries are wrong, too. The ns8250 entry should > be i8250, and I guess the 16750 and 16850 were also not made by national. But maybe we should keep the existing compatible strings because existing boards/bootloaders are providing them already? Roland ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx 2012-05-27 11:37 ` Roland Stigge @ 2012-05-27 12:07 ` Arnd Bergmann 0 siblings, 0 replies; 6+ messages in thread From: Arnd Bergmann @ 2012-05-27 12:07 UTC (permalink / raw) To: linux-arm-kernel On Sunday 27 May 2012, Roland Stigge wrote: > > Actually some of the other entries are wrong, too. The ns8250 entry should > > be i8250, and I guess the 16750 and 16850 were also not made by national. > > But maybe we should keep the existing compatible strings because > existing boards/bootloaders are providing them already? Right, we should only add to the list. Any entry that's already used potentially needs to stay in there as you say. Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-05-27 12:07 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-05-26 16:11 [PATCH RFC] serial/8250: Adjusting FIFO parameters for LPC32xx Roland Stigge 2012-05-27 2:32 ` Arnd Bergmann 2012-05-27 9:06 ` Roland Stigge 2012-05-27 10:23 ` Arnd Bergmann 2012-05-27 11:37 ` Roland Stigge 2012-05-27 12:07 ` Arnd Bergmann
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