linux-stable.git/drivers/tty/serial, branch v3.12.52 Linux kernel stable tree serial: 8250_dw: Fix deadlock in LCR workaround 2015-11-14T17:58:27+00:00 Peter Hurley peter@hurleysoftware.com 2015-03-11T13:19:16+00:00 9bc623ed14f83e2facf5ada94405d39c2a7be3fd commit 7fd6f640f2dd17dac6ddd6702c378cb0bb9cfa11 upstream. Trying to write console output from within the serial console driver while the port->lock is held causes recursive deadlock: CPU 0 spin_lock_irqsave(&port->lock) printk() console_unlock() call_console_drivers() serial8250_console_write() spin_lock_irqsave(&port->lock) ** DEADLOCK ** The 8250_dw i/o accessors try to write a console error message if the LCR workaround was unsuccessful. When the port->lock is already held (eg., when called from serial8250_set_termios()), this deadlocks. Make the error message a FIXME until a general solution is devised. Cc: Tim Kryger <tim.kryger@gmail.com> Reported-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 7fd6f640f2dd17dac6ddd6702c378cb0bb9cfa11 upstream.

Trying to write console output from within the serial console driver
while the port->lock is held causes recursive deadlock:

  CPU 0
spin_lock_irqsave(&port->lock)
printk()
  console_unlock()
    call_console_drivers()
      serial8250_console_write()
        spin_lock_irqsave(&port->lock)
** DEADLOCK **

The 8250_dw i/o accessors try to write a console error message if the
LCR workaround was unsuccessful. When the port->lock is already held
(eg., when called from serial8250_set_termios()), this deadlocks.

Make the error message a FIXME until a general solution is devised.

Cc: Tim Kryger <tim.kryger@gmail.com>
Reported-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
serial: 8250_pci: Add support for 12 port Exar boards 2015-11-12T13:09:06+00:00 Soeren Grunewald soeren.grunewald@desy.de 2015-06-11T07:25:04+00:00 cfcdadb344e6bce7f3a80da83322b36d5795c22e commit be32c0cf0462c36f482b5ddcff1d8371be1e183c upstream. The Exar XR17V358 can also be combined with a XR17V354 chip to act as a single 12 port chip. This works the same way as the combining two XR17V358 chips. But the reported device id then is 0x4358. Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit be32c0cf0462c36f482b5ddcff1d8371be1e183c upstream.

The Exar XR17V358 can also be combined with a XR17V354 chip to act as a
single 12 port chip. This works the same way as the combining two XR17V358
chips. But the reported device id then is 0x4358.

Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
serial: 8250_pci: Add support for 16 port Exar boards 2015-11-12T13:09:06+00:00 Soeren Grunewald soeren.grunewald@desy.de 2015-04-28T14:29:49+00:00 3e8c9dd24acc11db838781ca05305ed02484f2c3 commit 96a5d18bc1338786fecac73599f1681f59a59a8e upstream. The Exar XR17V358 chip usually provides only 8 ports. But two chips can be combined to act as a single 16 port chip. Therefor one chip is configured as master the second as slave by connecting the mode pin to VCC (master) or GND (slave). Then the master chip is reporting a different device-id depending on whether a slave is detected or not. The UARTs 8-15 are addressed from 0x2000-0x3fff. So the offset of 0x400 from UART to UART can be used to address all 16 ports as before. See: https://www.exar.com/common/content/document.ashx?id=1587 page 11 Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 96a5d18bc1338786fecac73599f1681f59a59a8e upstream.

The Exar XR17V358 chip usually provides only 8 ports. But two chips can be
combined to act as a single 16 port chip. Therefor one chip is configured
as master the second as slave by connecting the mode pin to VCC (master)
or GND (slave).

Then the master chip is reporting a different device-id depending on
whether a slave is detected or not. The UARTs 8-15 are addressed from
0x2000-0x3fff. So the offset of 0x400 from UART to UART can be used to
address all 16 ports as before.

See: https://www.exar.com/common/content/document.ashx?id=1587 page 11

Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
serial: 8250: don't bind to SMSC IrCC IR port 2015-09-30T08:59:54+00:00 Maciej S. Szmigiero mail@maciej.szmigiero.name 2015-08-02T21:11:52+00:00 01e34fe8efcb116223840e7ceaa42a6dca9bcf98 commit ffa34de03bcfbfa88d8352942bc238bb48e94e2d upstream. SMSC IrCC SIR/FIR port should not be bound to by (legacy) serial driver so its own driver (smsc-ircc2) can bind to it. Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit ffa34de03bcfbfa88d8352942bc238bb48e94e2d upstream.

SMSC IrCC SIR/FIR port should not be bound to by
(legacy) serial driver so its own driver (smsc-ircc2)
can bind to it.

Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
serial: imx: Fix DMA handling for IDLE condition aborts 2015-06-23T12:55:13+00:00 Philipp Zabel p.zabel@pengutronix.de 2015-05-19T08:54:09+00:00 0071013dc98c8e74d3923ed04828f5f9d173b02b commit 392bceedb107a3dc1d4287e63d7670d08f702feb upstream. The driver configures the IDLE condition to interrupt the SDMA engine. Since the SDMA UART ROM script doesn't clear the IDLE bit itself, this caused repeated 1-byte DMA transfers, regardless of available data in the RX FIFO. Also, when returning due to the IDLE condition, the UART ROM script already increased its counter, causing residue to be off by one. This patch clears the IDLE condition to avoid repeated 1-byte DMA transfers and decreases count by when the DMA transfer was aborted due to the IDLE condition, fixing serial transfers using DMA on i.MX6Q. Reported-by: Peter Seiderer <ps.report@gmx.net> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Tested-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 392bceedb107a3dc1d4287e63d7670d08f702feb upstream.

The driver configures the IDLE condition to interrupt the SDMA engine.
Since the SDMA UART ROM script doesn't clear the IDLE bit itself, this
caused repeated 1-byte DMA transfers, regardless of available data in the
RX FIFO. Also, when returning due to the IDLE condition, the UART ROM
script already increased its counter, causing residue to be off by one.

This patch clears the IDLE condition to avoid repeated 1-byte DMA transfers
and decreases count by when the DMA transfer was aborted due to the IDLE
condition, fixing serial transfers using DMA on i.MX6Q.

Reported-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
tty/serial: at91: maxburst was missing for dma transfers 2015-05-15T07:10:48+00:00 Ludovic Desroches ludovic.desroches@atmel.com 2015-04-16T14:58:12+00:00 7a90b15c3bb64b4d59badac51d5dda9a735087e3 commit a8d4e01637902311c5643b69a5c80e2805f04054 upstream. Maxburst was not set when doing the dma slave configuration. This value is checked by the recently introduced xdmac. It causes an error when doing the slave configuration and so prevents from using dma. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit a8d4e01637902311c5643b69a5c80e2805f04054 upstream.

Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
serial: of-serial: Remove device_type = "serial" registration 2015-05-15T07:10:47+00:00 Michal Simek michal.simek@xilinx.com 2015-04-14T10:03:09+00:00 b2ca4db9080145428a76c97e740bb0f857f27e2f commit 6befa9d883385c580369a2cc9e53fbf329771f6d upstream. Do not probe all serial drivers by of_serial.c which are using device_type = "serial"; property. Only drivers which have valid compatible strings listed in the driver should be probed. When PORT_UNKNOWN is setup probe will fail anyway. Arnd quotation about driver historical background: "when I wrote that driver initially, the idea was that it would get used as a stub to hook up all other serial drivers but after that, the common code learned to create platform devices from DT" This patch fix the problem with on the system with xilinx_uartps and 16550a where of_serial failed to register for xilinx_uartps and because of irq_dispose_mapping() removed irq_desc. Then when xilinx_uartps was asking for irq with request_irq() EINVAL is returned. Signed-off-by: Michal Simek <michal.simek@xilinx.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 6befa9d883385c580369a2cc9e53fbf329771f6d upstream.

Do not probe all serial drivers by of_serial.c which are using
device_type = "serial"; property. Only drivers which have valid
compatible strings listed in the driver should be probed.

When PORT_UNKNOWN is setup probe will fail anyway.

Arnd quotation about driver historical background:
"when I wrote that driver initially, the idea was that it would
get used as a stub to hook up all other serial drivers but after
that, the common code learned to create platform devices from DT"

This patch fix the problem with on the system with xilinx_uartps and
16550a where of_serial failed to register for xilinx_uartps and because
of irq_dispose_mapping() removed irq_desc. Then when xilinx_uartps was asking
for irq with request_irq() EINVAL is returned.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
tty: serial: fsl_lpuart: clear receive flag on FIFO flush 2015-04-22T06:58:42+00:00 Stefan Agner stefan@agner.ch 2015-03-13T13:51:51+00:00 dabdec3b92b1da15cf89f6140d33c6e7744c1c94 commit 8e4934c6d6c659e22b1b746af4196683e77ce6ca upstream. When the receiver was enabled during startup, a character could have been in the FIFO when the UART get initially used. The driver configures the (receive) watermark level, and flushes the FIFO. However, the receive flag (RDRF) could still be set at that stage (as mentioned in the register description of UARTx_RWFIFO). This leads to an interrupt which won't be handled properly in interrupt mode: The receive interrupt function lpuart_rxint checks the FIFO count, which is 0 at that point (due to the flush during initialization). The problem does not manifest when using DMA to receive characters. Fix this situation by explicitly read the status register, which leads to clearing of the RDRF flag. Due to the flush just after the status flag read, a explicit data read is not to required. Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 8e4934c6d6c659e22b1b746af4196683e77ce6ca upstream.

When the receiver was enabled during startup, a character could
have been in the FIFO when the UART get initially used. The
driver configures the (receive) watermark level, and flushes the
FIFO. However, the receive flag (RDRF) could still be set at that
stage (as mentioned in the register description of UARTx_RWFIFO).
This leads to an interrupt which won't be handled properly in
interrupt mode: The receive interrupt function lpuart_rxint checks
the FIFO count, which is 0 at that point (due to the flush
during initialization). The problem does not manifest when using
DMA to receive characters.

Fix this situation by explicitly read the status register, which
leads to clearing of the RDRF flag. Due to the flush just after
the status flag read, a explicit data read is not to required.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Change email address for 8250_pci 2015-04-09T11:14:04+00:00 Russell King rmk+kernel@arm.linux.org.uk 2015-03-06T10:49:21+00:00 6be916ce95ab1159dea6e6bc89f465ee758f4e0d commit f2e0ea861117bda073d1d7ffbd3120c07c0d5d34 upstream. I'm still receiving reports to my email address, so let's point this at the linux-serial mailing list instead. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit f2e0ea861117bda073d1d7ffbd3120c07c0d5d34 upstream.

I'm still receiving reports to my email address, so let's point this
at the linux-serial mailing list instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
tty/serial: at91: fix error handling in atmel_serial_probe() 2015-03-01T22:34:20+00:00 Cyrille Pitchen cyrille.pitchen@atmel.com 2014-12-09T13:31:34+00:00 79abbf657e16a14ab146498001f94398c5a5de32 commit 6fbb9bdf0f3fbe23aeff806489791aa876adaffb upstream. -EDEFER error wasn't handle properly by atmel_serial_probe(). As an example, when atmel_serial_probe() is called for the first time, we pass the test_and_set_bit() test to check whether the port has already been initalized. Then we call atmel_init_port(), which may return -EDEFER, possibly returned before by clk_get(). Consequently atmel_serial_probe() used to return this error code WITHOUT clearing the port bit in the "atmel_ports_in_use" mask. When atmel_serial_probe() was called for the second time, it used to fail on the test_and_set_bit() function then returning -EBUSY. When atmel_serial_probe() fails, this patch make it clear the port bit in the "atmel_ports_in_use" mask, if needed, before returning the error code. Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 6fbb9bdf0f3fbe23aeff806489791aa876adaffb upstream.

-EDEFER error wasn't handle properly by atmel_serial_probe().
As an example, when atmel_serial_probe() is called for the first time, we pass
the test_and_set_bit() test to check whether the port has already been
initalized. Then we call atmel_init_port(), which may return -EDEFER, possibly
returned before by clk_get(). Consequently atmel_serial_probe() used to return
this error code WITHOUT clearing the port bit in the "atmel_ports_in_use" mask.
When atmel_serial_probe() was called for the second time, it used to fail on
the test_and_set_bit() function then returning -EBUSY.

When atmel_serial_probe() fails, this patch make it clear the port bit in the
"atmel_ports_in_use" mask, if needed, before returning the error code.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>