Marking structures as packed as the following 2 results:
- the compiler doesn't insert any holes in the structures
e.g. if variables are not naturally aligned
- the compiler doesn't assume the base address of the struct to be
naturally aligned
The 2nd effect results in the compiler (depending on the target
architecture) to generate bad code, as unaligned access is not
possible on all archs.
Mark the structs as aligned to 4 bytes, using the not-so-beautiful
__ALIGN_BEGIN and __ALIGN_END macros.
This saves some bytes and generates probably faster code.
| add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-468 (-468)
| Function old new delta
| USBD_GS_CAN_EP0_RxReady 684 568 -116
| main 2712 2360 -352
| Total: Before=17138, After=16670, chg -2.73%
There is a pair of USB requests ( GS_USB_BREQ_GET_USER_ID and
_SET_USER_ID) that is not supported by the linux driver, and not used by
any known software :
https://github.com/candle-usb/candleLight_fw/issues/91
Since the firmware returns a unique serial #, there doesn't appear to be
any use case for assigning a user ID. Using a whole flash page for that
purpose can be wasteful on bigger targets .
This removes all the relevant code and adjusts the linker scripts
accordingly.
In commit
40e1997d45
[1] GS_CAN_FEATURE_GET_STATE has been added to the Linux driver.
Document this bit here accordingly.
The new feature ("GS_CAN_FEATURE_GET_STATE") indicates that the state
of the CAN controller can be queried with the new
GS_USB_BREQ_GET_STATE control message.
[1] https://git.kernel.org/torvalds/c/40e1997d4551e6053fc2f61959628da474775dc5
In commit
1f1835264d
[1] Bus Error Reporting has been added to the Linux driver. Document
this bit here accordingly.
The new feature ("GS_CAN_FEATURE_BERR_REPORTING") indicates that the
bus error reporting in the CAN controller can switched on and off with
the GS_CAN_MODE_BERR_REPORTING mode bit in the GS_USB_BREQ_MODE
control message.
[1] https://git.kernel.org/torvalds/c/1f1835264d81da03fcd05646542a622678b379d6
Add a USB message which controls a GPIO for a specified CAN bus.
The GPIO activates a SSR to connect a 120Ohm terminating resistor
to the specified CAN bus.
Signed-off-by: Daniel Trevitz <daniel.trevitz@wika.com>
with help from include-what-you-use (iwyu-tool). It's not quite clever
enough to understand our intent of including "hal_include.h" but still
offers good suggestions.
Use tabs for leading whitespace and spaces for continuation lines.
Besides that inconsistent whitespace looks odd, it causes unnecessary
merge conflicts.
The documents a workaround for a NXP chip errata on LPC546xx
controllers (Errata sheet LPC546xx / USB.15).
According to the document corruption can occur when the following
conditions are met:
* A TX (IN) transfer happens after a RX (OUT) transfer.
* The RX (OUT) transfer length is 4 + N * 16 (N >= 0) bytes.
Even though the struct gs_host_frame has a size of 76 bytes for a FD
frame, which does not apply to the above rule, corruption could be
seen.
Adding a dummy byte to break the second condition also on transfer
lengths with 4 + N * 8 bytes reliably circumvents USB transfer data
corruption.
The firmware can now request this quirk by setting
GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX.
The CANtact FD and other devices implement a gs-usb compatible USB
protocol. The protocol has been extended to support CAN-FD and the
changes on the Linux gs_usb driver will be mainlined soon.
This patch adds the new GS_CAN_MODE_*, GS_CAN_FEATURE_*,
GS_USB_BREQ_DATA_BITTIMING, and GS_CAN_FLAG_* bits as well as struct
gs_host_frame_canfd to the candlelight driver.
This is mainly for documentation purpose, as the STM32F042 and
STM32F072 don't support CAN-FD. But there are some ports to CAN-FD
capable STM32 µC that can make use of these definitions.
[1] https://github.com/linklayer/gs_usb_fd/issues/2
The bits in GS_CAN_MODE_ correspond to the bits in GS_CAN_FEATURE_*.
This means the bits 5 and 6 of GS_CAN_MODE_ are not "free", document
this by adding a comment to the corresponding GS_CAN_FEATURE_*.
The project uses tabs with a length of 4 spaces, and spaces for
continuation, so lets use that for the whole project. There are
many trailing whitespaces and empty lines here and there; get
rid of them as well.
