| Message ID | 1446855503-25881-1-git-send-email-timur@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Nov 06, 2015 at 06:18:23PM -0600, Timur Tabi wrote: > Add support the "mmio32" earlycon option for the pl011 device. If > specified in the earlycon parameter, all reads/writes to pl011 registers > during early console will use 32-bit accessors. Normally the function > uses 8-bit writes. > > Normal console uses the "access_32b" field of the vendor data structure > to determine whether the registers needs 32-bit accessors. Early console > is used before the vendor data is available, so we need a different > mechanism to choose the accessor. > > Example: > > earlycon=pl011,mmio32,0x3ced1000 > > Signed-off-by: Timur Tabi <timur@codeaurora.org> > --- > > This patch applies on top of Russell's 12-part amba-pl011.c patchset. Which I didn't apply, so can you resend this after he resends his? thanks, greg k-h
Greg Kroah-Hartman wrote: >> > >> >Example: >> > >> > earlycon=pl011,mmio32,0x3ced1000 >> > >> >Signed-off-by: Timur Tabi<timur@codeaurora.org> >> >--- >> > >> >This patch applies on top of Russell's 12-part amba-pl011.c patchset. > Which I didn't apply, so can you resend this after he resends his? Yes, I will resend all of my pl011-releated patches after Russell's patches are reworked and accepted.
On Sun, Dec 13, 2015 at 12:06 AM, Greg Kroah-Hartman <greg@kroah.com> wrote: >> Example: >> >> earlycon=pl011,mmio32,0x3ced1000 >> >> Signed-off-by: Timur Tabi <timur@codeaurora.org> >> --- >> >> This patch applies on top of Russell's 12-part amba-pl011.c patchset. > > Which I didn't apply, so can you resend this after he resends his? I see that some of Russell's patches are now in tty-next. Does that make them official? There was some disagreement about the usage of access_32b vs uap->port.iotype for determining whether we need 32-bit accessors or not.
On Thu, Dec 17, 2015 at 09:55:30AM -0600, Timur Tabi wrote: > On Sun, Dec 13, 2015 at 12:06 AM, Greg Kroah-Hartman <greg@kroah.com> wrote: > > >> Example: > >> > >> earlycon=pl011,mmio32,0x3ced1000 > >> > >> Signed-off-by: Timur Tabi <timur@codeaurora.org> > >> --- > >> > >> This patch applies on top of Russell's 12-part amba-pl011.c patchset. > > > > Which I didn't apply, so can you resend this after he resends his? > > I see that some of Russell's patches are now in tty-next. Does that > make them official? Unless Russell asks me to revert them, they will show up in the next merge window. > There was some disagreement about the usage of > access_32b vs uap->port.iotype for determining whether we need 32-bit > accessors or not. There was? I missed that, please send follow-on patches to resolve the issue if there is one. thanks, greg k-h
Greg Kroah-Hartman wrote: >> >There was some disagreement about the usage of >> >access_32b vs uap->port.iotype for determining whether we need 32-bit >> >accessors or not. > There was? I missed that, please send follow-on patches to resolve the > issue if there is one. I can submit a patch that provides an alternative implementation, but I'm pretty sure Russell won't like it. For reference: http://www.spinics.net/lists/linux-serial/msg19710.html Russell said that UPIO_MEM is supposed to be literally only 8-bit access, but then Peter Hurley posted this: http://www.spinics.net/lists/linux-serial/msg19930.html which you applied. So my patch would remove access_32b and use UPIO_MEM32/UPIO_MEM instead. It would be a little weird having both patches in your tree, I guess.
On 12/17/2015 08:47 AM, Timur Tabi wrote: > Greg Kroah-Hartman wrote: >>> >There was some disagreement about the usage of >>> >access_32b vs uap->port.iotype for determining whether we need 32-bit >>> >accessors or not. >> There was? I missed that, please send follow-on patches to resolve the >> issue if there is one. > > I can submit a patch that provides an alternative implementation, but I'm pretty sure Russell won't like it. > > For reference: > > http://www.spinics.net/lists/linux-serial/msg19710.html > > Russell said that UPIO_MEM is supposed to be literally only 8-bit access, but then Peter Hurley posted this: > > http://www.spinics.net/lists/linux-serial/msg19930.html > > which you applied. So my patch would remove access_32b and use UPIO_MEM32/UPIO_MEM instead. It would be a little weird having both patches in your tree, I guess. I think it'll be ok if you just send a patch to use UPIO_MEM32 instead; I think that situation mostly had to do with inertia and not wanting to rebase a series like that (which I can appreciate). The worst that happens is Russell objects, but I think there's a good case for the simpler UPIO_MEM32 usage, which plays nice with earlycon. Regards, Peter Hurley
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 22a4b68..2436f62 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -992,10 +992,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. unspecified, the h/w is not initialized. pl011,<addr> + pl011,mmio32,<addr> Start an early, polled-mode console on a pl011 serial port at the specified address. The pl011 serial port must already be setup and configured. Options are not - yet supported. + yet supported. If 'mmio32' is specified, then only + the driver will use only 32-bit accessors to read/write + the device registers. msm_serial,<addr> Start an early, polled-mode console on an msm serial diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 373b152..6643ed9 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2301,10 +2301,13 @@ static struct console amba_console = { static void pl011_putc(struct uart_port *port, int c) { - while (readl(port->membase + REG_FR) & UART01x_FR_TXFF) + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) ; - writeb(c, port->membase + REG_DR); - while (readl(port->membase + REG_FR) & UART01x_FR_BUSY) + if (port->iotype == UPIO_MEM32) + writel(c, port->membase + UART01x_DR); + else + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) ; }
Add support the "mmio32" earlycon option for the pl011 device. If specified in the earlycon parameter, all reads/writes to pl011 registers during early console will use 32-bit accessors. Normally the function uses 8-bit writes. Normal console uses the "access_32b" field of the vendor data structure to determine whether the registers needs 32-bit accessors. Early console is used before the vendor data is available, so we need a different mechanism to choose the accessor. Example: earlycon=pl011,mmio32,0x3ced1000 Signed-off-by: Timur Tabi <timur@codeaurora.org> --- This patch applies on top of Russell's 12-part amba-pl011.c patchset. Documentation/kernel-parameters.txt | 5 ++++- drivers/tty/serial/amba-pl011.c | 9 ++++++--- 2 files changed, 10 insertions(+), 4 deletions(-)