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  1. 21 May, 2021 8 commits
    • Peng Li's avatar
      net: wan: fix the code style issue about trailing statements · eab99481
      Peng Li authored 
      Trailing statements should be on next line.
Signed-off-by: default avatarPeng Li <lipeng321@huawei.com>
Signed-off-by: default avatarGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      eab99481
    • Peng Li's avatar
      net: wan: add some required spaces · 974221c6
      Peng Li authored 
      Add space required after that close brace '}'.
Add space required before the open parenthesis '('.
Signed-off-by: default avatarPeng Li <lipeng321@huawei.com>
Signed-off-by: default avatarGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      974221c6
    • Peng Li's avatar
      net: wan: fix an code style issue about "foo* bar" · 49262579
      Peng Li authored 
      Fix the checkpatch error as "foo* bar" should be "foo *bar".
Signed-off-by: default avatarPeng Li <lipeng321@huawei.com>
Signed-off-by: default avatarGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      49262579
    • David S. Miller's avatar
      Merge branch 'sja1105-spi' · 44be5c42
      David S. Miller authored 
      Vladimir Oltean says:

====================
Adapt the sja1105 DSA driver to the SPI controller's transfer limits

This series changes the SPI transfer procedure in sja1105 to take into
consideration the buffer size limitations that the SPI controller driver
might have.

Changes in v2:
Remove the driver's use of cs_change and send multiple, smaller SPI
messages instead of a single large one.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      44be5c42
    • Vladimir Oltean's avatar
      net: dsa: sja1105: adapt to a SPI controller with a limited max transfer size · 718bad0e
      Vladimir Oltean authored 
      The static config of the sja1105 switch is a long stream of bytes which
is programmed to the hardware in chunks (portions with the chip select
continuously asserted) of max 256 bytes each. Each chunk is a
spi_message composed of 2 spi_transfers: the buffer with the data and a
preceding buffer with the SPI access header.

Only that certain SPI controllers, such as the spi-sc18is602 I2C-to-SPI
bridge, cannot keep the chip select asserted for that long.
The spi_max_transfer_size() and spi_max_message_size() functions are how
the controller can impose its hardware limitations upon the SPI
peripheral driver.

For the sja1105 driver to work with these controllers, both buffers must
be smaller than the transfer limit, and their sum must be smaller than
the message limit.

Regression-tested on a switch connected to a controller with no
limitations (spi-fsl-dspi) as well as with one with caps for both
max_transfer_size and max_message_size (spi-sc18is602).
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      718bad0e
    • Vladimir Oltean's avatar
      net: dsa: sja1105: send multiple spi_messages instead of using cs_change · ca021f0d
      Vladimir Oltean authored 
      The sja1105 driver has been described by Mark Brown as "not using the
[ SPI ] API at all idiomatically" due to the use of cs_change:
https://patchwork.kernel.org/project/netdevbpf/patch/20210520135031.2969183-1-olteanv@gmail.com/

According to include/linux/spi/spi.h, the chip select is supposed to be
asserted for the entire length of a SPI message, as long as cs_change is
false for all member transfers. The cs_change flag changes the following:

(i) When a non-final SPI transfer has cs_change = true, the chip select
    should temporarily deassert and then reassert starting with the next
    transfer.
(ii) When a final SPI transfer has cs_change = true, the chip select
     should remain asserted until the following SPI message.

The sja1105 driver only uses cs_change for its first property, to form a
single SPI message whose layout can be seen below:

                                             this is an entire, single spi_message
           _______________________________________________________________________________________________
          /                                                                                               \
          +-------------+---------------+-------------+---------------+ ... +-------------+---------------+
          | hdr_xfer[0] | chunk_xfer[0] | hdr_xfer[1] | chunk_xfer[1] |     | hdr_xfer[n] | chunk_xfer[n] |
          +-------------+---------------+-------------+---------------+ ... +-------------+---------------+
cs_change      false          true           false           true                false          false

           ____________________________  _____________________________       _____________________________
CS line __/                            \/                             \ ... /                             \__

The fact of the matter is that spi_max_message_size() has an ambiguous
meaning if any non-final transfer has cs_change = true.

If the SPI master has a limitation in that it cannot keep the chip
select asserted for more than, say, 200 bytes (like the spi-sc18is602),
the normal thing for it to do is to implement .max_transfer_size and
.max_message_size, and limit both to 200: in the "worst case" where
cs_change is always false, then the controller can, indeed, not send
messages larger than 200 bytes.

But the fact that the SPI controller's max_message_size does not
necessarily mean that we cannot send messages larger than that.
Notably, if the SPI master special-cases the transfers with cs_change
and treats every chip select toggling as an entirely new transaction,
then a SPI message can easily exceed that limit. So there is a
temptation to ignore the controller's reported max_message_size when
using cs_change = true in non-final transfers.

But that can lead to false conclusions. As Mark points out, the SPI
controller might have a different kind of limitation with the max
message size, that has nothing at all to do with how long it can keep
the chip select asserted.
For example, that might be the case if the device is able to offload the
chip select changes to the hardware as part of the data stream, and it
packs the entire stream of commands+data (corresponding to a SPI
message) into a single DMA transfer that is itself limited in size.

So the only thing we can do is avoid ambiguity by not using cs_change at
all. Instead of sending a single spi_message, we now send multiple SPI
messages as follows:

                  spi_message 0                 spi_message 1                       spi_message n
           ____________________________   ___________________________        _____________________________
          /                            \ /                           \      /                             \
          +-------------+---------------+-------------+---------------+ ... +-------------+---------------+
          | hdr_xfer[0] | chunk_xfer[0] | hdr_xfer[1] | chunk_xfer[1] |     | hdr_xfer[n] | chunk_xfer[n] |
          +-------------+---------------+-------------+---------------+ ... +-------------+---------------+
cs_change      false          true           false           true                false          false

           ____________________________  _____________________________       _____________________________
CS line __/                            \/                             \ ... /                             \__

which is clearer because the max_message_size limit is now easier to
enforce. What is transmitted on the wire stays, of course, the same.

Additionally, because we send no more than 2 transfers at a time, we now
avoid dynamic memory allocation too, which might be seen as an
improvement by some.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ca021f0d
    • Peter Geis's avatar
      net: phy: add driver for Motorcomm yt8511 phy · 48e8c6f1
      Peter Geis authored 
      Add a driver for the Motorcomm yt8511 phy that will be used in the
production Pine64 rk3566-quartz64 development board.
It supports gigabit transfer speeds, rgmii, and 125mhz clk output.
Signed-off-by: default avatarPeter Geis <pgwipeout@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      48e8c6f1
    • YueHaibing's avatar
      net: xilinx_emaclite: Do not print real IOMEM pointer · d0d62baa
      YueHaibing authored 
      Printing kernel pointers is discouraged because they might leak kernel
memory layout.  This fixes smatch warning:

drivers/net/ethernet/xilinx/xilinx_emaclite.c:1191 xemaclite_of_probe() warn:
 argument 4 to %08lX specifier is cast from pointer
Signed-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d0d62baa
  3. 20 May, 2021 32 commits
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