From b696ea7c641c2172aff67297e9c0f13d8d46620f Mon Sep 17 00:00:00 2001 From: Hector Martin Date: Thu, 23 Dec 2021 19:30:17 +0900 Subject: [PATCH 098/171] brcmfmac: pcie: Provide a buffer of random bytes to the device Newer Apple firmwares on chipsets without a hardware RNG require the host to provide a buffer of 256 random bytes to the device on initialization. This buffer is present immediately before NVRAM, suffixed by a footer containing a magic number and the buffer length. This won't affect chips/firmwares that do not use this feature, so do it unconditionally. Reviewed-by: Linus Walleij Signed-off-by: Hector Martin --- .../broadcom/brcm80211/brcmfmac/pcie.c | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c index 2ca2c4b603cf..1e2afca5a60b 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -1625,6 +1626,13 @@ brcmf_pcie_init_share_ram_info(struct brcmf_pciedev_info *devinfo, return 0; } +struct brcmf_random_seed_footer { + __le32 length; + __le32 magic; +}; + +#define BRCMF_RANDOM_SEED_MAGIC 0xfeedc0de +#define BRCMF_RANDOM_SEED_LENGTH 0x100 static int brcmf_pcie_download_fw_nvram(struct brcmf_pciedev_info *devinfo, const struct firmware *fw, void *nvram, @@ -1656,11 +1664,32 @@ static int brcmf_pcie_download_fw_nvram(struct brcmf_pciedev_info *devinfo, brcmf_pcie_write_ram32(devinfo, devinfo->ci->ramsize - 4, 0); if (nvram) { + size_t rand_len = BRCMF_RANDOM_SEED_LENGTH; + struct brcmf_random_seed_footer footer = { + .length = cpu_to_le32(rand_len), + .magic = cpu_to_le32(BRCMF_RANDOM_SEED_MAGIC), + }; + void *randbuf; + brcmf_dbg(PCIE, "Download NVRAM %s\n", devinfo->nvram_name); address = devinfo->ci->rambase + devinfo->ci->ramsize - nvram_len; memcpy_toio(devinfo->tcm + address, nvram, nvram_len); brcmf_fw_nvram_free(nvram); + + /* Some Apple chips/firmwares expect a buffer of random data + * to be present before NVRAM + */ + brcmf_dbg(PCIE, "Download random seed\n"); + + address -= sizeof(footer); + memcpy_toio(devinfo->tcm + address, &footer, sizeof(footer)); + + address -= rand_len; + randbuf = kzalloc(rand_len, GFP_KERNEL); + get_random_bytes(randbuf, rand_len); + memcpy_toio(devinfo->tcm + address, randbuf, rand_len); + kfree(randbuf); } else { brcmf_dbg(PCIE, "No matching NVRAM file found %s\n", devinfo->nvram_name); -- 2.34.1