wifi: rtw88: add RTL8723B/RTL8723BS support

This is the second of two series adding support for the Realtek RTL8723B 802.11n chipset and its RTL8723BS SDIO variant to rtw88. The preparation series has landed in rtw-next, so this series carries the chip register definitions, the BB/RF/AGC tables, the chip driver, the SDIO bind and the build glue.

The first and fourth patches are the shared-core changes. The first moves the CCK power detect setter out of rtw88xxa.c into phy.c as rtw_phy_cck_pd_set(), so this chip can use it without pulling in rtw88_88xxa. The fourth moves the definitions RTL8723B shares with RTL8703B into rtw8723x.h. The five chip patches apply on top and can be read on their own.

The driver supports:

- RTL8723B / RTL8723BS, SDIO only
- 2.4 GHz 802.11n, HT20 and HT40
- one spatial stream
- station mode

Only station mode has been validated. The common rtw88 core advertises AP and IBSS for all chips, so those modes are advertised for RTL8723BS as well, but neither has been tested. An out-of-tree tester has reported AP mode associating without DHCP completing. The five additional SDIO IDs are included for parity with the existing staging driver, and only the 0xb723 device has been exercised.

The chip driver requests:

rtw88/rtw8723b_fw.bin

This is the version 41 firmware extracted from the Realtek rtl8723bs vendor driver. It was submitted separately to linux-firmware with its extraction provenance and carries Ping-Ke Shih's Reviewed-by. There is no known native rtw88 RTL8723B firmware.

The implementation is based on the initial RTL8723B work by Michael Straube:

https://github.com/mistraube/rtw88/tree/rtl8723bs

Michael's Co-developed-by and Signed-off-by tags are present on the three chip-code patches containing code derived from that work.

The known limitations are unchanged. Bluetooth coexistence depends on the BT firmware's status reports. During A2DP streaming those reports identify a connected link but do not expose the active profile, so the WiFi coexistence logic cannot make a correct traffic-aware decision. WiFi throughput can fall sharply while audio remains smooth. This is documented rather than guessed around in the WiFi driver. The intermittent RTL8723BS firmware failure to leave LPS also remains, and instrumentation shows a firmware stall rather than a polling timeout that a longer budget would fix.

Testing
=======

The exact seven-commit branch builds with W=1, with no new warnings, and links all rtw88 modules with real modpost. Sparse and smatch were run over the rtw88 directory. Sparse is clean. Smatch reports nothing in the 8723B files, and its only output is an existing container_of static assertion from include/net/neighbour.h while checking usb.c. checkpatch --strict is clean apart from the complex-macro report on TRANS_SEQ_END, which is an initializer macro that rtw8703b.c already defines in the same way, and the "does MAINTAINERS need updating" reminder on the file-adding patches, which the existing REALTEK WIRELESS DRIVER (rtw88) entry already answers with its
F: line. git diff --check is clean and all seven commits are GPG-signed.

Hardware validation covered module identity, boot, scan, authentication, association, WPA2 key negotiation and DHCP, TCP and UDP traffic in both directions, ten scans while connected, and twenty module reload and reassociate cycles. dmesg is clean, with no warnings, no errors and no TX-report, H2C or leave-LPS messages. The extended soak added six 30 second TCP runs, UDP saturation in both access categories with no loss, a 2000 packet ping run with no loss, and three idle power save periods with a clean wake. The test machine provides only s2idle, so suspend and resume are not covered.

Changes in v8:
- a new patch moves the receive PHY status layout, the SDIO aggregation burst fields and four baseband registers out of rtw8703b.h into rtw8723x.h, and renames struct phy_status_8703b to struct phy_status_8723x. The chip driver no longer includes the header of a sibling chip. It is a pure move, rtw8703b.c only follows the new struct name;
- the vendor driver's name for that layout, phy_status_rpt_8192cd, is in

    the commit message rather than in the source;

- dropped the long comment above the CCK swing table;
- the two receive PHY status helpers take void *phy_raw and read the CCK LNA and VGA fields with u8_get_bits().

Luka Gejak (7):
wifi: rtw88: move the 88xxa CCK power detect setter to phy.c
wifi: rtw88: 8723b: add the RTL8723B register definitions
wifi: rtw88: 8723b: add the RTL8723B BB, RF and AGC tables
wifi: rtw88: move the shared 8723x definitions to rtw8723x.h
wifi: rtw88: 8723b: add the RTL8723B chip driver
wifi: rtw88: 8723bs: add the RTL8723BS SDIO bind
wifi: rtw88: 8723bs: enable building the RTL8723BS driver

 drivers/net/wireless/realtek/rtw88/Kconfig    |   18 +
 drivers/net/wireless/realtek/rtw88/Makefile   |    6 +
 drivers/net/wireless/realtek/rtw88/phy.c      |   39 +
 drivers/net/wireless/realtek/rtw88/phy.h      |    1 +
 drivers/net/wireless/realtek/rtw88/reg.h      |   34 +
 drivers/net/wireless/realtek/rtw88/rtw8703b.c |    4 +-
 drivers/net/wireless/realtek/rtw88/rtw8703b.h |   63 -
 drivers/net/wireless/realtek/rtw88/rtw8723b.c | 2534 +++++++++++++++++
 drivers/net/wireless/realtek/rtw88/rtw8723b.h |   14 +
 .../wireless/realtek/rtw88/rtw8723b_table.c   |  861 ++++++
 .../wireless/realtek/rtw88/rtw8723b_table.h   |   17 +
 .../net/wireless/realtek/rtw88/rtw8723bs.c    |   59 +
 drivers/net/wireless/realtek/rtw88/rtw8723x.h |   60 +
 drivers/net/wireless/realtek/rtw88/rtw8812a.c |    2 +-
 drivers/net/wireless/realtek/rtw88/rtw8821a.c |    2 +-
 drivers/net/wireless/realtek/rtw88/rtw88xxa.c |   38 -
 drivers/net/wireless/realtek/rtw88/rtw88xxa.h |    1 -
 17 files changed, 3647 insertions(+), 106 deletions(-)
 create mode 100644 drivers/net/wireless/realtek/rtw88/rtw8723b.c
 create mode 100644 drivers/net/wireless/realtek/rtw88/rtw8723b.h
 create mode 100644 drivers/net/wireless/realtek/rtw88/rtw8723b_table.c
 create mode 100644 drivers/net/wireless/realtek/rtw88/rtw8723b_table.h
 create mode 100644 drivers/net/wireless/realtek/rtw88/rtw8723bs.c

2.55.0