linux-stable.git/drivers/tty/serial/sh-sci.c, branch linux-6.11.y

Revert "serial: sh-sci: Clean sci_ports[0] after at earlycon exit"

2024-12-05T12:54:16+00:00

commit 718632467d88e98816fa01ab12681ef1c2aa56f8 upstream.

This reverts commit 3791ea69a4858b81e0277f695ca40f5aae40f312.

It was reported to cause boot-time issues, so revert it for now.

Reported-by: Geert Uytterhoeven 
Fixes: 3791ea69a485 ("serial: sh-sci: Clean sci_ports[0] after at earlycon exit")
Cc: stable 
Cc: Claudiu Beznea 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Clean sci_ports[0] after at earlycon exit

2024-12-05T12:54:16+00:00

commit 3791ea69a4858b81e0277f695ca40f5aae40f312 upstream.

The early_console_setup() function initializes the sci_ports[0].port with
an object of type struct uart_port obtained from the object of type
struct earlycon_device received as argument by the early_console_setup().

It may happen that later, when the rest of the serial ports are probed,
the serial port that was used as earlycon (e.g., port A) to be mapped to a
different position in sci_ports[] and the slot 0 to be used by a different
serial port (e.g., port B), as follows:

sci_ports[0] = port A
sci_ports[X] = port B

In this case, the new port mapped at index zero will have associated data
that was used for earlycon.

In case this happens, after Linux boot, any access to the serial port that
maps on sci_ports[0] (port A) will block the serial port that was used as
earlycon (port B).

To fix this, add early_console_exit() that clean the sci_ports[0] at
earlycon exit time.

Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea 
Link: https://lore.kernel.org/r/20241106120118.1719888-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Add support for RZ/V2H(P) SoC

2024-06-24T14:09:37+00:00

Add serial support for RZ/V2H(P) SoC with earlycon.

The SCIF interface in the Renesas RZ/V2H(P) is similar to that available
in the RZ/G2L (R9A07G044) SoC, with the following differences:

- RZ/V2H(P) SoC has three additional interrupts: one for Tx end/Rx ready
  and two for Rx and Tx buffer full, all of which are edge-triggered.
- RZ/V2H(P) supports asynchronous mode, whereas RZ/G2L supports both
  synchronous and asynchronous modes.
- There are differences in the configuration of certain registers such
  as SCSMR, SCFCR, and SCSPTR between the two SoCs.

To handle these differences on RZ/V2H(P) SoC SCIx_RZV2H_SCIF_REGTYPE
is added.

Signed-off-by: Lad Prabhakar 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20240604170513.522631-6-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: simplify locking when re-issuing RXDMA fails

2024-05-10T10:48:33+00:00

Avoid a superfluous unlock/lock-pair by simply moving the printout to
the end of bailing out.

Signed-off-by: Wolfram Sang 
Link: https://lore.kernel.org/r/20240506114016.30498-10-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: let timeout timer only run when DMA is scheduled

2024-05-10T10:48:33+00:00

The hrtimer for RXDMA timeout was unconditionally restarted in the RXDMA
complete handler ignoring the fact that setting up DMA may fail and PIO
is used instead. Explicitly stop the timer when DMA is completed and
only restart it when setting up DMA was successful. This makes the
intention of the timer much clearer, the driver easier to understand and
simplifies assumptions about the timer. The latter avoids race
conditions if these assumptions were not met or confused.

Signed-off-by: Wolfram Sang 
Link: https://lore.kernel.org/r/20240506114016.30498-9-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: describe locking requirements for invalidating RXDMA

2024-05-10T10:48:33+00:00

Make sure everyone knows that calling this function needs protection.

Signed-off-by: Wolfram Sang 
Link: https://lore.kernel.org/r/20240506114016.30498-8-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: protect invalidating RXDMA on shutdown

2024-05-10T10:48:33+00:00

The to-be-fixed commit removed locking when invalidating the DMA RX
descriptors on shutdown. It overlooked that there is still a rx_timer
running which may still access the protected data. So, re-add the
locking.

Reported-by: Dirk Behme 
Closes: https://lore.kernel.org/r/ee6c9e16-9f29-450e-81da-4a8dceaa8fc7@de.bosch.com
Fixes: 2c4ee23530ff ("serial: sh-sci: Postpone DMA release when falling back to PIO")
Signed-off-by: Wolfram Sang 
Link: https://lore.kernel.org/r/20240506114016.30498-7-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: switch from circ_buf to kfifo

2024-04-09T13:28:03+00:00

Switch from struct circ_buf to proper kfifo. kfifo provides much better
API, esp. when wrap-around of the buffer needs to be taken into account.
Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example.

Kfifo API can also fill in scatter-gather DMA structures, so it easier
for that use case too. Look at lpuart_dma_tx() for example. Note that
not all drivers can be converted to that (like atmel_serial), they
handle DMA specially.

Note that usb-serial uses kfifo for TX for ages.

omap needed a bit more care as it needs to put a char into FIFO to start
the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to
do kfifo_dma_out_prepare twice: once to find out the tx_size (to find
out if it is worths to do DMA at all -- size >= 4), the second time for
the actual transfer.

All traces of circ_buf are removed from serial_core.h (and its struct
uart_state).

Signed-off-by: Jiri Slaby (SUSE) 
Cc: Al Cooper 
Cc: Matthias Brugger 
Cc: AngeloGioacchino Del Regno 
Cc: Kumaravel Thiagarajan 
Cc: Tharun Kumar P 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Richard Genoud 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Claudiu Beznea 
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: Maciej W. Rozycki 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Fabio Estevam 
Cc: Neil Armstrong 
Cc: Kevin Hilman 
Cc: Jerome Brunet 
Cc: Martin Blumenstingl 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Bjorn Andersson 
Cc: Konrad Dybcio 
Cc: Pali Rohár 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: Aneesh Kumar K.V 
Cc: Naveen N. Rao 
Cc: Manivannan Sadhasivam 
Cc: Krzysztof Kozlowski 
Cc: Alim Akhtar 
Cc: Laxman Dewangan 
Cc: Thierry Reding 
Cc: Jonathan Hunter 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: David S. Miller 
Cc: Hammer Hsieh 
Cc: Peter Korsgaard 
Cc: Timur Tabi 
Cc: Michal Simek 
Cc: Sumit Semwal 
Cc: Christian König 
Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Call sci_serial_{in,out}() directly

2024-03-05T13:37:32+00:00

Unlike the 8250 serial driver complex, the sh-sci driver uses only a
single pair of functions to read and write serial port registers.
Hence there is no need to incur the overhead of calling them through
indirection, like the serial_port_{in,out}() wrappers do.

Replace all calls to these wrappers by direct calls to
sci_serial_{in,out}().

Remove the setup of the uart_port.serial_{in,out}() callbacks.  After
removal of all calls to serial_port_{in,out}() in the sh-sci driver, the
only remaining user is uart_xchar_out(), which the sh-sci driver does
not use.

Signed-off-by: Geert Uytterhoeven 
Acked-by: John Paul Adrian Glaubitz 
Link: https://lore.kernel.org/r/51e79d601cb9d9d63822d3773d3cf05a96868612.1709548811.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: convert not to use dma_request_slave_channel()

2023-11-23T19:33:03+00:00

dma_request_slave_channel() is deprecated. dma_request_chan() should
be used directly instead.

Switch to the preferred function and update the error handling accordingly.

Signed-off-by: Christophe JAILLET 
Link: https://lore.kernel.org/r/d6773b9bd88dbbbea06bc6d5cd59aa117b1ee2ee.1700416841.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman