The tegra serial driver has two paths through which receive data is
copied up to the tty layer. These are:
1. DMA completion callback
2. UART RX interrupt
A UART RX interrupt occurs for either RX_TIMEOUT (data has been sitting
in the Rx FIFO for more than 4 character times without being read
because there is not enough data to reach the trigger level), End of
Receive Data event (receiver detects that data stops coming in for more
than 4 character times) or a receive error.
In the RX interrupt path, the following happens ...
- All RX DMA transfers are stopped
- Any data in the DMA buffer and RX FIFO are copied up to the tty layer.
- DMA is restarted/primed for the RX path
In the DMA completion callback, the DMA buffer is copied up to the tty
layer but there is no check to see if the RX interrupt could have
occurred between the DMA interrupt firing the the DMA callback running.
Hence, if a RX interrupt was to occur shortly after the DMA completion
interrupt, it is possible that the RX interrupt path has already copied
the DMA buffer before the DMA callback has been called. Therefore, when
the DMA callback is called, if the DMA is already in-progress, then this
indicates that the UART RX interrupt has already occurred and there is
nothing to do in the DMA callback. This race condition can cause
duplicated data to be received.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
[jonathanh@nvidia.com: Moved async_tx_ack() call to after check to see
if DMA has completed because if the DMA is in progress we do not need
to ACK yet. Changed the print from dev_info to dev_debug. Updated
changelog to add more commentary on the race condition based upon
feedback from author.]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is only necessary to read data from the dma buffer when the count
value is non-zero and hence, tegra_uart_copy_rx_to_tty() so only be
called when this is the case.
Although, this was being tested for in two places, there is a third
place where this was not tested. However, instead of adding another
if-statement prior to calling tegra_uart_copy_rx_to_tty(), move the test
inside the function.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
[jonathanh@nvidia.com: Re-worked patch to move the check for the count
value inside the function tegra_uart_copy_rx_to_tty(). Updated
changelog with more commentary.]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For all tegra devices (up to t210), there is a hardware issue that
requires software to wait for 3 UART clock periods after enabling
the TX fifo, otherwise data could be lost.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For all tegra devices (up to t210), there is a hardware issue that
requires software to wait for 32 UART clock periods for the flush
to propagate otherwise TX data could be post. Add a helper function
to wait for N UART clock periods and update delay following FIFO
flush to be 32 UART clock cycles.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port.type has already been set by of_platform_serial_setup()
called from a few lines above.
Setting it to the same value is redundant.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port.fifosize member has already been copied at 8 lines above.
Maybe the compiler optimization can clean it away, but just in case.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Early console functions are only used during the early boot stage.
This change just saves a small amount of memory footprint.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When nr_uarts was set to 0 (via config or 8250_core.nr_uarts), we crash
early on x86 because serial8250_isa_init_ports dereferences base_ops
which remains NULL. In fact, there is nothing to do for all the callers
of serial8250_isa_init_ports if there are no uarts.
Based on suggestions by Peter Hurley.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform_device_id is not modified by the driver and core uses it as
const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Staticize symbols not exported and not used outside of file.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform_device_id is not modified by the driver and core uses it as
const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform_device_id is not modified by the driver and core uses it as
const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The code it refers to was removed in commit b545e4f406 ("serial:
sh-sci: Compute overrun_bit without using baud rate algo").
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
error_mask is the union of all error indicating bits in the SCxSR
register, while overrun_mask may apply to a different register (SCLSR),
depending on the SCI variant.
Hence overrun_mask should only be ORed into error_mask if it applies to
the SCxSR register.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The various SCI implementations use 3 different methods to signal
overrun errors:
- Bit SCI_ORER in register SCxSR on SCI,
- Bit SCIFA_ORER in register SCxSR on SCIFA and SCIFB, and SCIF on
SH7705/SH7720/SH7721,
- Bit SCLSR_ORER in (optional!) register SCLSR on (H)SCIF.
However:
1. sci_handle_fifo_overrun()
a. handles (H)SCIF and SCIFA/SCIFB only,
b. treats SCIF on SH7705/SH7720/SH7721 incorrectly,
2. sci_mpxed_interrupt()
a. treats SCIF on SH7705/SH7720/SH7721 incorrectly,
b. ignores that not all SCIFs have the SCLSR register, causing
"Invalid register access" WARN()ings.
To fix the above:
1. Determine and store the correct register enum during
initialization,
2. Replace the duplicated buggy switch statements by using the stored
register enum,
3. Add the missing existence check to sci_mpxed_interrupt().
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing overrun bit definition for (H)SCIF.
Replace overrun_bit by overrun_mask, so we can use the existing
defines instead of hardcoded values.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing overrun error bit in SCxSR on SCIFA/SCIFB and SCIF on
SH7705/SH7720/SH7721.
Document what the corresponding bit(s) on plain SCIF are used for.
Sort the components of SCIF_DEFAULT_ERROR_MASK by reverse definition
order.
Replace the hardcoded values in the SCxSR_*_CLEAR macros by proper
defines. Use bit masks (negations of sets of bits) to make it more
obvious which bits are being cleared.
Assembler output (on sh) was compared before and after this commit:
- For the first branch of the big "#if defined(...) || ..." construct,
the code has changed slightly, as 32-bit bitmasks can be loaded in a
single instruction, unlike the old large 16-bit constants (the SCxSR
register is 16 bit, so we don't care about the top 16 bits),
- For the second branch, the generated code is identical.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the register definitions for the Serial Port Control and Data
Registers on SCIFA/SCIFB, which are needed for RTS/CTS pin control.
Extracted from patches by Magnus Damm <damm+renesas@opensource.se>.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing register bit definitions to set the RTS pin and read the
CTS pin on (H)SCIF.
Extracted from patches by Magnus Damm <damm+renesas@opensource.se>.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move private register definitions and enums from the public
<linux/serial_sci.h> header file to the driver private "sh-sci.h" header
file.
The common Serial Control Register definitions are left in the public
header file, as they're needed to fill in plat_sci_port.scscr on legacy
systems not using DT.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Pat Gefre <pfg@sgi.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Pat Gefre <pfg@sgi.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
CC: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
CC: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Mikael Starvik <starvik@axis.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
CC: Takashi Iwai <tiwai@suse.de>
CC: Imre Deak <imre.deak@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not be doing assignments within an if () block
so fix up the code to not do this.
change was created using Coccinelle.
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In SiRF platform, there are different fifo size of uart and usp,
with the fifosize configuration changes in different chips, we
can not use port line to decide how to check FIFO full,empty and
level.
There is a direct mapping between FIFO HW register layout with
fifo size, so move to use fifosize as the input to check fifo
status.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In different platform of SiRF SoCs, there is no same uart and usp-uart
numbers, it is not convenient to use hard-coded ports array and port
lines.
here we drop the hard-coded ports table , and drop "cell-index". then
move to use alias id to get line.
for example:
aliases {
serial0 = &uart0;
serial1 = &uart1;
serial2 = &uart2;
serial3 = &uart3;
serial4 = &uart4;
serial5 = &uart5;
serial6 = &uart6;
serial9 = &usp2;
};
at the same, enlarge the max port number according to the chip with the most
UART.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add 8250 MTK UART driver to support earlycon device tree.
Earlycon take effect by
add "earlycon" in kernel boot argument
add "linux,sdtout-path" property in device tree file
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The mtk 8250 needs two clocks, one for providing the baudrate and
one that needs to be enabled for register accesses. The latter has
not been supported, this patch adds support for it. It is optional
for now since not all SoCs provide a bus clock.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The pm_runtime callbacks already enable and disable the device.
Use them in probe() and remove() instead of duplicating the
code. This allows us to concentrate more code for enabling/disabling
the UART in a single place.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a struct device * is present clk_get should be used rather
than of_clk_get. Use the devm variant of this function to be able to
drop the clk_put in the error and remove pathes. While at it fix
a wrong error message.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the driver has probed successfully the clk pointer is always valid,
so no need to test for it.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function meson_uart_release_port() inappropriately try to
iounmap() a resource managed by devm_ioremap_nocache().
The function meson_uart_release_port() maybe called by uart_ioctl()
that means meson_uart_release_port() is not called from within a
probe or remove function, for safety, I convert iounmap() to
devm_iounmap().
Signed-off-by: Firo Yang <firogm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The rx_running flag should show if DMA is currently active. However
there is a window between when the flag is set/cleared and when
the DMA is started/stopped. Because the flag is queried from both
hard and soft irq contexts, the driver can make incorrect
decisions and do things like start a DMA transfer using a buffer
that is already setup to be used for a DMA transfer.
This patch adds a spinlock to synchronize the rx_running flag and
close the above mentioned window.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 8250_omap serial driver relies on dmaengine_pause() actually
pausing the DMA transfer. Before this patch dmaengine_pause() is
a NOP for non-cylic DMA transfers. This allowed the 8250_omap
driver to read DMA buffers while the DMA was still active,
resulting in lost serial data.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When stopping a DMA transfer with interrupts disabled it is possible
that the DMA transfer completes before the events are cleared. In
this case the completion interrupt will be pending, causing a
completion callback after the transfer was stopped.
By clearing the completion interrupt for the stopping channel it is
ensured that no completion event will be generated after the stop.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If NO_DMA=y:
drivers/built-in.o: In function `ifx_spi_free_device':
ifx6x60.c:(.text+0x96d9a): undefined reference to `dma_free_coherent'
drivers/built-in.o: In function `ifx_spi_spi_probe':
ifx6x60.c:(.text+0x978a2): undefined reference to `dma_alloc_coherent'
While DMA is optional in this driver, and is used only if
ifx_modem_platform_data.use_dma is set, there are currently no in-tree
users of ifx_modem_platform_data (and thus of this driver), so just make
it depend on HAS_DMA.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Shardar Shariff Md