[ Upstream commit 1f1496a923 ]
Setup the port uartclk in sifive_serial_probe() so that the base baud
rate is correctly printed during device probe instead of always showing
"0". I.e. the probe message is changed from
38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1,
base_baud = 0) is a SiFive UART v0
to the correct:
38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1,
base_baud = 115200) is a SiFive UART v0
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4cbd7814bb ]
SiFive's UART has a software controller clock divider that produces the
final baud rate clock. Whenever the clock that drives the UART is
changed this divider must be updated accordingly, and given that these
two events are controlled by software they cannot be done atomically.
During the period between updating the UART's driving clock and internal
divider the UART will transmit a different baud rate than what the user
has configured, which will probably result in a corrupted transmission
stream.
The SiFive UART has a FIFO, but due to an issue with the programming
interface there is no way to directly determine when the UART has
finished transmitting. We're essentially restricted to dead reckoning
in order to figure that out: we can use the FIFO's TX busy register to
figure out when the last frame has begun transmission and just delay for
a long enough that the last frame is guaranteed to get out.
As far as the actual implementation goes: I've modified the existing
existing clock notifier function to drain both the FIFO and the shift
register in on PRE_RATE_CHANGE. As far as I know there is no hardware
flow control in this UART, so there's no good way to ask the other end
to stop transmission while we can't receive (inserting software flow
control messages seems like a bad idea here).
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Tested-by: Yash Shah <yash.shah@sifive.com>
Link: https://lore.kernel.org/r/20200307042637.83728-1-palmer@dabbelt.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 17b4efdf4e upstream.
An uninitialised spin lock for sifive serial console raises a bad
magic spin_lock error as reported and discussed here [1].
Initialising the spin lock resolves the issue.
The fix is tested on HiFive Unleashed A00 board with Linux 5.7-rc4
and OpenSBI v0.7
[1] https://lore.kernel.org/linux-riscv/b9fe49483a903f404e7acc15a6efbef756db28ae.camel@wdc.com
Fixes: 45c054d081 ("tty: serial: add driver for the SiFive UART")
Reported-by: Atish Patra <Atish.Patra@wdc.com>
Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1589019852-21505-2-git-send-email-sagar.kadam@sifive.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-45-swboyd@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a serial driver for the SiFive UART, found on SiFive FU540 devices
(among others).
The underlying serial IP block is relatively basic, and currently does
not support serial break detection. Further information on the IP
block can be found in the documentation and Chisel sources:
https://static.dev.sifive.com/FU540-C000-v1.0.pdfhttps://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/uart
This driver was written in collaboration with Wesley Terpstra
<wesley@sifive.com>.
Tested on a SiFive HiFive Unleashed A00 board, using BBL and the open-
source FSBL (using a DT file based on what's targeted for mainline).
This revision incorporates changes based on comments by Julia Lawall
<julia.lawall@lip6.fr>, Emil Renner Berthing <kernel@esmil.dk>, and
Andreas Schwab <schwab@suse.de>. Thanks also to Andreas for testing
the driver with his userspace and reporting a bug with the
set_termios implementation.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Wesley Terpstra <wesley@sifive.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Andreas Schwab <schwab@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Damien Le Moal