serial: cpm_uart: Switch to irq_get_nr_irqs()

Use the irq_get_nr_irqs() function instead of the global variable
'nr_irqs'. Prepare for changing 'nr_irqs' from an exported global
variable into a vari

serial: cpm_uart: Switch to irq_get_nr_irqs()

Use the irq_get_nr_irqs() function instead of the global variable
'nr_irqs'. Prepare for changing 'nr_irqs' from an exported global
variable into a variable with file scope.

Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

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serial: Switch back to struct platform_driver::remove()

After commit 0edb555a65d1 ("platform: Make platform_driver::remove()
return void") .remove() is (again) the right callback to implement for
pl

serial: Switch back to struct platform_driver::remove()

After commit 0edb555a65d1 ("platform: Make platform_driver::remove()
return void") .remove() is (again) the right callback to implement for
platform drivers.

Convert all platform drivers below drivers/tty/serial to use .remove(),
with the eventual goal to drop struct platform_driver::remove_new(). As
.remove() and .remove_new() have the same prototypes, conversion is done
by just changing the structure member name in the driver initializer.

Signed-off-by: Uwe Kleine-König <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tty: serial: switch from circ_buf to kfifo

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 pl

tty: serial: switch from circ_buf to kfifo

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

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serial: cpm: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error h

serial: cpm: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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serial: cpm_uart: Use port lock wrappers

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, a

serial: cpm_uart: Use port lock wrappers

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.

So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.

All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.

To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.

Converted with coccinelle. No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: John Ogness <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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serial: cpm_uart: Remove cpm_uart/ subdirectory

cpm_uart/ subdirectory only has cpm_uart_core.c and cpm_uart.h now.

Move them up and remove cpm_uart/ directory while renaming
cpm_uart_core.c as cpm

serial: cpm_uart: Remove cpm_uart/ subdirectory

cpm_uart/ subdirectory only has cpm_uart_core.c and cpm_uart.h now.

Move them up and remove cpm_uart/ directory while renaming
cpm_uart_core.c as cpm_uart.c

Signed-off-by: Christophe Leroy <[email protected]>
Link: https://lore.kernel.org/r/9b8b8f89fc386480030f5339abe307541ae436a6.1691068700.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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