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Message-Id: <20230214080034.3828-3-marcan@marcan.st>
Date: Tue, 14 Feb 2023 17:00:34 +0900
From: Hector Martin <marcan@...can.st>
To: Arend van Spriel <aspriel@...il.com>,
Franky Lin <franky.lin@...adcom.com>,
Hante Meuleman <hante.meuleman@...adcom.com>,
Kalle Valo <kvalo@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: Sven Peter <sven@...npeter.dev>,
Alyssa Rosenzweig <alyssa@...enzweig.io>,
Linus Walleij <linus.walleij@...aro.org>,
asahi@...ts.linux.dev, linux-wireless@...r.kernel.org,
brcm80211-dev-list.pdl@...adcom.com,
SHA-cyfmac-dev-list@...ineon.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Hector Martin <marcan@...can.st>
Subject: [PATCH 2/2] 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 for all Apple platforms (those with an Apple OTP).
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Hector Martin <marcan@...can.st>
---
.../broadcom/brcm80211/brcmfmac/pcie.c | 32 +++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
index f320b6ce8bff..a7b88ab609c2 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
@@ -15,6 +15,7 @@
#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/io.h>
+#include <linux/random.h>
#include <asm/unaligned.h>
#include <soc.h>
@@ -1653,6 +1654,13 @@ 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,
@@ -1689,6 +1697,30 @@ 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);
--
2.35.1
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