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wifi: brcmfmac: pcie: Provide a buffer of random bytes to the device

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[ Upstream commit 91918ce88d9fef408bb12c46a27c73d79b604c20 ]

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 for all Apple platforms (those with an Apple OTP).

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Julian Calaby <julian.calaby@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230214080034.3828-3-marcan@marcan.st
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Hector Martin 2023-02-14 17:00:34 +09:00 committed by Greg Kroah-Hartman
parent 4e7a81b5e7
commit c35105f375
1 changed files with 32 additions and 0 deletions
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32
drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
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@ -13,6 +13,7 @@
#include <linux/bcma/bcma.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/random.h>
#include <asm/unaligned.h>
#include <soc.h>
@ -1631,6 +1632,13 @@ 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,
@ -1667,6 +1675,30 @@ static int brcmf_pcie_download_fw_nvram(struct brcmf_pciedev_info *devinfo,
nvram_len;
memcpy_toio(devinfo->tcm + address, nvram, nvram_len);
brcmf_fw_nvram_free(nvram);
if (devinfo->otp.valid) {
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;
/* 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);