can: mcp251xfd: __mcp251xfd_chip_set_mode(): increase poll timeout

The mcp251xfd controller needs an idle bus to enter 'Normal CAN 2.0
mode' or . The maximum length of a CAN frame is 736 bits (64 data
bytes, CAN-FD, EFF mode, worst case bit stuffing and interframe
spacing). For low bit rates like 10 kbit/s the arbitrarily chosen
MCP251XFD_POLL_TIMEOUT_US of 1 ms is too small.

Otherwise during polling for the CAN controller to enter 'Normal CAN
2.0 mode' the timeout limit is exceeded and the configuration fails
with:

| $ ip link set dev can1 up type can bitrate 10000
| [ 731.911072] mcp251xfd spi2.1 can1: Controller failed to enter mode CAN 2.0 Mode (6) and stays in Configuration Mode (4) (con=0x068b0760, osc=0x00000468).
| [ 731.927192] mcp251xfd spi2.1 can1: CRC read error at address 0x0e0c (length=4, data=00 00 00 00, CRC=0x0000) retrying.
| [ 731.938101] A link change request failed with some changes committed already. Interface can1 may have been left with an inconsistent configuration, please check.
| RTNETLINK answers: Connection timed out

Make MCP251XFD_POLL_TIMEOUT_US timeout calculation dynamic. Use
maximum of 1ms and bit time of 1 full 64 data bytes CAN-FD frame in
EFF mode, worst case bit stuffing and interframe spacing at the
current bit rate.

For easier backporting define the macro MCP251XFD_FRAME_LEN_MAX_BITS
that holds the max frame length in bits, which is 736. This can be
replaced by can_frame_bits(true, true, true, true, CANFD_MAX_DLEN) in
a cleanup patch later.

Fixes: 55e5b97f003e8 ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Signed-off-by: Fedor Ross <fedor.ross@ifm.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230717-mcp251xfd-fix-increase-poll-timeout-v5-1-06600f34c684@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: regmap: optimizing transfer size for CRC transfers size 1

For CRC transfers with size 1 it is more efficient to use the
write_safe command instead of the write_crc command. This saves the
length byte on the SPI transfer.

changes since v1: https://lore.kernel.org/all/20230127124258.2764-1-thomas.kopp@microchip.com
- change logic to remove 1 level of indention

Link: https://lore.kernel.org/all/20230202141811.2581795-1-mkl@pengutronix.de
Signed-off-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: silence clang's -Wunaligned-access warning

clang emits a -Wunaligned-access warning on union
mcp251xfd_tx_ojb_load_buf.

The reason is that field hw_tx_obj (not declared as packed) is being
packed right after a 16 bits field inside a packed struct:

| union mcp251xfd_tx_obj_load_buf {
| struct __packed {
| struct mcp251xfd_buf_cmd cmd;
| /* ^ 16 bits fields */
| struct mcp251xfd_hw_tx_obj_raw hw_tx_obj;
| /* ^ not declared as packed */
| } nocrc;
| struct __packed {
| struct mcp251xfd_buf_cmd_crc cmd;
| struct mcp251xfd_hw_tx_obj_raw hw_tx_obj;
| __be16 crc;
| } crc;
| } ____cacheline_aligned;

Starting from LLVM 14, having an unpacked struct nested in a packed
struct triggers a warning. c.f. [1].

This is a false positive because the field is always being accessed
with the relevant put_unaligned_*() function. Adding __packed to the
structure declaration silences the warning.

[1] https://github.com/llvm/llvm-project/issues/55520

Link: https://lore.kernel.org/all/20220518114357.55452-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add support for mcp251863

The MCP251863 device is a CAN-FD controller (MCP2518FD) with an
integrated transceiver (ATA6563). This patch add support for the new
device.

Link: https://lore.kernel.org/all/20220419072805.2840340-3-mkl@pengutronix.de
Cc: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: increase number of RX-FIFOs to 3 and increase max TX-FIFO depth to 16

This patch increases the number of RX-FIFOs to 3 and the max TX-FIFO
depth to 16. This leads to the following default ring configuration.

CAN-2.0 mode:

| FIFO setup: TEF: 0x400: 8*12 bytes = 96 bytes
| FIFO setup: RX-0: FIFO 1/0x460: 32*20 bytes = 640 bytes
| FIFO setup: RX-1: FIFO 2/0x6e0: 32*20 bytes = 640 bytes
| FIFO setup: RX-2: FIFO 3/0x960: 16*20 bytes = 320 bytes
| FIFO setup: TX: FIFO 4/0xaa0: 8*16 bytes = 128 bytes
| FIFO setup: free: 224 bytes

CAN-FD mode:

| FIFO setup: TEF: 0x400: 4*12 bytes = 48 bytes
| FIFO setup: RX-0: FIFO 1/0x430: 16*76 bytes = 1216 bytes
| FIFO setup: RX-1: FIFO 2/0x8f0: 4*76 bytes = 304 bytes
| FIFO setup: TX: FIFO 3/0xa20: 4*72 bytes = 288 bytes
| FIFO setup: free: 192 bytes

With the previously added ethtool ring configuration support the RAM
on the chip can now be runtime configured between RX and TX buffers.

Link: https://lore.kernel.org/20220313083640.501791-13-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add TX IRQ coalescing ethtool support

This patch adds support ethtool based configuration for the TX IRQ
coalescing added in the previous patch.

Link: https://lore.kernel.org/20220313083640.501791-12-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add TX IRQ coalescing support

This patch adds TX IRQ coalescing support to the driver.

The implemented algorithm is similar to the RX IRQ coalescing support
added in the previous patch.

Link: https://lore.kernel.org/20220313083640.501791-11-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add RX IRQ coalescing ethtool support

This patch adds support ethtool based configuration for the RX IRQ
coalescing added in the previous patch.

Link: https://lore.kernel.org/20220313083640.501791-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add RX IRQ coalescing support

This patch adds RX IRQ coalescing support to the driver.

The mcp251xfd chip doesn't support proper hardware based coalescing,
so this patch tries to implemented it in software. The RX-FIFO offers
a "FIFO not empty" interrupt, which is used if no coalescing is
active.

With activated RX IRQ coalescing the "FIFO not empty" interrupt is
disabled in the RX IRQ handler and the "FIFO half full" or "FIFO full
interrupt" (depending on RX max coalesced frames IRQ) is used instead.
To avoid RX CAN frame starvation a hrtimer is setup with RX coalesce
usecs IRQ,on timer expiration the "FIFO not empty" is enabled again.

Support for ethtool configuration is added in the next patch.

Link: https://lore.kernel.org/20220313083640.501791-9-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: add support for runtime configurable RX/TX ring parameters

This patch adds runtime configurable RX and TX ring parameters via
ethtool to the driver.

Link: https://lore.kernel.org/20220313083640.501791-8-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: update macros describing ring, FIFO and RAM layout

So far the configuration of the hardware FIFOs is hard coded and
depend only on the selected CAN mode (CAN-2.0 or CAN-FD).

This patch updates the macros describing the ring, FIFO and RAM layout
to prepare for the next patches that add support for runtime
configurable ring parameters via ethtool.

Link: https://lore.kernel.org/20220313083640.501791-7-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: prepare support for runtime configurable RX/TX ring parameters

This patch prepares the driver for runtime configurable RX and TX ring
parameters. The actual runtime config support will be added in the
next patch.

Link: https://lore.kernel.org/20220313083640.501791-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ethtool: add support

This patch adds basic ethtool support (to query the current and
maximum ring parameters) to the driver.

Link: https://lore.kernel.org/20220313083640.501791-5-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: mcp251xfd_priv: introduce macros specifying the number of supported TEF/RX/TX rings

This patch introduces macros to define the number of supported TEF, RX
and TX rings. As well as some assertions as sanity checks.

Link: https://lore.kernel.org/all/20220217103826.2299157-9-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: prepare for multiple RX-FIFOs

This patch prepares the driver to use more than one RX-FIFO. Having a
bigger RX buffer is beneficial in high load situations, where the
system temporarily cannot keep up reading CAN frames from the chip.
Using a bigger RX buffer also allows to implement RX IRQ coalescing,
which will be added in a later patch series.

If using more than 1 RX-FIFO the driver has to figure out, which FIFOs
have RX'ed CAN frames pending. This is indicated by a set bit in the
RXIF register, which is positioned directly after the interrupt status
register INT. If more than 1 RX-FIFO is used, the driver reads both
registers in 1 transfer.

The mcp251xfd_handle_rxif() function iterates over all RX rings and
reads out the RX'ed CAN frames for for all pending FIFOs. To keep the
logic for the 1 RX-FIFO only case in mcp251xfd_handle_rxif() simple,
the driver marks that FIFO pending in mcp251xfd_ring_init().

The chip has a dedicated RX interrupt line to signal pending RX'ed
frames. If connected to an input GPIO and the driver will skip the
initial read of the interrupt status register (INT) and directly read
the pending RX'ed frames if the line is active. The driver assumes the
1st RX-FIFO pending (a read of the RXIF register would re-introduce
the skipped initial read of the INT register). Any other pending
RX-FIFO will be served in the main interrupt handler.

Link: https://lore.kernel.org/all/20220217103826.2299157-8-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: mcp251xfd_ring_init(): checked RAM usage of ring setup

With this patch the usage of the on-chip RAM is checked. In the
current driver the FIFO setup is fixed and always fits into the RAM.

With an upcoming patch series the ring and FIFO setup will be more
dynamic. Although using more RAM than available should not happen, but
add this safety check, just in case.

Link: https://lore.kernel.org/all/20220217103826.2299157-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: change order of TX and RX FIFOs

This patch actually changes the order of the TX and RX FIFOs.

This gives the opportunity to minimize the number of SPI transfers in
the IRQ handler. The read of the IRQ status register and RX FIFO
status registers can be combined into single SPI transfer. If the RX
ring uses FIFO 1, the overall length of the transfer is smaller than
in the original layout, where the RX FIFO comes after the TX FIFO.

Link: https://lore.kernel.org/all/20220217103826.2299157-5-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: ring: prepare to change order of TX and RX FIFOs

This patch improves the initialization of the TX and RX rings. The
initialization functions are now called with pointers to the next free
address (in the on chip RAM) and next free hardware FIFO. The rings
are initialized using these values and the pointers are modified to
point to the next free elements.

This means the order of the mcp251xfd_ring_init_*() functions
specifies the order of the rings in the hardware FIFO. This makes it
possible to change the order of the TX and RX FIFOs, which is done in
the next patch.

This gives the opportunity to minimize the number of SPI transfers in
the IRQ handler. The read of the IRQ status register and RX FIFO
status registers can be combined into single SPI transfer. If the RX
ring uses FIFO 1, the overall length of the transfer is smaller than
in the original layout, where the RX FIFO comes after the TX FIFO.

Link: https://lore.kernel.org/all/20220217103826.2299157-4-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: introduce struct mcp251xfd_tx_ring::nr and ::fifo_nr and make use of it

This patch removes the hard coded assumption that the TX ring uses
hardware FIFO 1. This allows the hardware FIFO 1 to be used for RX and
the next free FIFO for TX.

This gives the opportunity to minimize the number of SPI transfers in
the IRQ handler. The read of the IRQ status register and RX FIFO
status registers can be combined into single SPI transfer. If the RX
ring uses FIFO 1, the overall length of the transfer is smaller than
in the original layout, where the RX FIFO comes after the TX FIFO.

Link: https://lore.kernel.org/all/20220217103826.2299157-2-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add support for internal PLL

The PLL is enabled if the configured clock is less than or equal to 10 times
the max clock frequency.

The device will operate with two different SPI speeds. A slow speed determined
by the clock without the PLL enabled, and a fast speed derived from the
frequency with the PLL enabled.

Link: https://lore.kernel.org/all/20220207131047.282110-16-mkl@pengutronix.de
Link: https://lore.kernel.org/all/20201015124401.2766-3-mas@csselectronics.com
Co-developed-by: Magnus Aagaard Sørensen <mas@csselectronics.com>
Signed-off-by: Magnus Aagaard Sørensen <mas@csselectronics.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: introduce and make use of mcp251xfd_is_fd_mode()

This patch replaces the open coded check, if the chip's FIFOs are
configured for CAN-FD mode, by the newly introduced function
mcp251xfd_is_fd_mode().

Link: https://lore.kernel.org/all/20220105154300.1258636-14-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move ring init into separate function

This patch moves the ring initialization from the mcp251xfd core file
into a separate one to make the driver a bit more orderly.

Link: https://lore.kernel.org/all/20220105154300.1258636-13-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move chip FIFO init into separate file

This patch moves the chip FIFO initialization from the mcp251xfd core
file into a separate one to make the driver a bit more orderly.

Link: https://lore.kernel.org/all/20220105154300.1258636-12-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move TEF handling into separate file

This patch moves the TEF handling from the mcp251xfd core file into a
separate one to make the driver a bit more orderly.

Link: https://lore.kernel.org/all/20220105154300.1258636-11-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move TX handling into separate file

This patch moves the TX handling from the mcp251xfd core file into a
separate one to make the driver a bit more orderly.

Link: https://lore.kernel.org/all/20220105154300.1258636-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move RX handling into separate file

This patch moves the RX handling from the mcp251xfd core file into a
separate one to make the driver a bit more orderly.

Link: https://lore.kernel.org/all/20220105154300.1258636-9-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: mcp251xfd.h: sort function prototypes

The .c files in the Makefile are ordered alphabetically. This patch
groups the function prototypes by their corresponding .c file and
brings the into the same order.

Link: https://lore.kernel.org/all/20220105154300.1258636-8-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: mark some instances of struct mcp251xfd_priv as const

With the patch 07ff4aed015c ("time/timecounter: Mark 1st argument of
timecounter_cyc2time() as const") some instances of the struct
mcp251xfd_priv can be marked as const. This patch marks these as
const.

Link: https://lore.kernel.org/r/20210813091027.159379-1-mkl@pengutronix.de
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add HW timestamp infrastructure

This patch add the HW timestamping infrastructure. The mcp251xfd has a
free running timer of 32 bit width, running at max 40MHz, which wraps
around every 107 seconds. The current timestamp is latched into RX and
TEF objects automatically be the CAN controller.

This patch sets up a cyclecounter, timecounter and delayed worker
infrastructure (which runs every 45 seconds) to convert the timer into
a proper 64 bit based ns timestamp.

Link: https://lore.kernel.org/r/20210304160328.2752293-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: mcp251xfd_get_timestamp(): move to mcp251xfd.h

This is a preparation patch, it moves the mcp251xfd_get_timestamp()
function into the mcp251xfd.h file.

Link: https://lore.kernel.org/r/20210304160328.2752293-5-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move netdevice.h to mcp251xfd.h

The netdevice.h header is needed in mcp251xfd.h, so that it can be
included without further headers.

Link: https://lore.kernel.org/r/20210304160328.2752293-4-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add dev coredump support

For easier debugging this patch adds dev coredump support to the
driver. A dev coredump is generated in case the chip fails to start or
an error in the interrupt handler is detected.

The dev coredump consists of all chip registers and chip memory, as
well as the driver's internal state of the TEF-, RX- and TX-FIFOs, it
can be analyzed with the mcp251xfd-dump tool of the can-utils:

https://github.com/linux-can/can-utils/tree/master/mcp251xfd
Link: https://lore.kernel.org/r/20210304160328.2752293-2-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: add missing _MASK postfix to MCP251XFD_OBJ_FLAGS_DLC

As MCP251XFD_OBJ_FLAGS_DLC is a mask, add the missing _MASK postfix,
that all other masks in the driver have.

Link: https://lore.kernel.org/r/20210128104644.2982125-7-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: tef-path: reduce number of SPI core requests to set UINC bit

Reduce the number of separate SPI core requests when setting the UINC bit in
the TEF FIFO, and instead batch them up into a single SPI core request.

Link: https://lore.kernel.org/r/20201126132144.351154-6-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: move struct mcp251xfd_tef_ring definition

This patch moves the struct mcp251xfd_tef_ring upwards, so that the union
mcp251xfd_write_reg_buf and struct spi_transfer can be made members of it.

Link: https://lore.kernel.org/r/20201126132144.351154-5-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: struct mcp251xfd_priv::tef to array of length 1

This patch converts the struct mcp251xfd_tef_ring member within the struct
mcp251xfd_priv into an array of length one. This way all rings (tef, tx and rx)
can be accessed in the same way.

Link: https://lore.kernel.org/r/20201126132144.351154-4-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp25xxfd: rx-path: reduce number of SPI core requests to set UINC bit

Reduce the number of separate SPI core requests when setting the UINC bit in
the RX FIFO, and instead batch them up into a single SPI core request.

Link: https://github.com/marckleinebudde/linux/issues/4
Link: https://lore.kernel.org/r/20201126132144.351154-3-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Ursula Maplehurst <ursula@kangatronix.co.uk>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: mcp25xxfd_ring_alloc(): add define instead open coding the maximum number of RX objects

This patch add a define for the maximum number of RX objects instead of open
coding it.

Link: https://lore.kernel.org/r/20201126132144.351154-2-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: rename all remaining occurrence to mcp251xfd

In [1] Geert noted that the autodetect compatible for the mcp25xxfd driver,
which is "microchip,mcp25xxfd" might be too generic and overlap with upcoming,
but incompatible chips.

In the previous patch the autodetect DT compatbile has been renamed to
"microchip,mcp251xfd", this patch changes all non user facing occurrence of
"mcp25xxfd" to "mcp251xfd" and "MCP25XXFD" to "MCP251XFD".

[1] http://lore.kernel.org/r/CAMuHMdVkwGjr6dJuMyhQNqFoJqbh6Ec5V2b5LenCshwpM2SDsQ@mail.gmail.com

Link: https://lore.kernel.org/r/20200930091424.792165-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: mcp251xfd: rename driver files and subdir to mcp251xfd

In [1] Geert noted that the autodetect compatible for the mcp25xxfd driver,
which is "microchip,mcp25xxfd" might be too generic and overlap with upcoming,
but incompatible chips.

In the previous patch the autodetect DT compatbile has been renamed to
"microchip,mcp251xfd", this patch changes the name of the driver subdir and the
individual files accordinly.

[1] http://lore.kernel.org/r/CAMuHMdVkwGjr6dJuMyhQNqFoJqbh6Ec5V2b5LenCshwpM2SDsQ@mail.gmail.com

Link: https://lore.kernel.org/r/20200930091424.792165-8-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>