From 61bd5e5683244a564ecfe31c73575ee0bc708ccc Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 12 Jan 2012 12:19:34 -0800 Subject: [PATCH] brcmsmac: fix reading of PCI sprom contents It appears that you can only read the sprom contents with aligned 16-bit reads: anything else causes at least some versions of the broadcom chipset to abort the PCI transaction, returning 0xff. This apparently doesn't trigger very often, because most setups don't use an external srom chip, and the OTP sprom loading doesn't have this issue. But at least the current 11" Macbook Air does trigger it, and wireless communications were broken as a result. Acked-by: Arend van Spriel Signed-off-by: Linus Torvalds --- .../net/wireless/brcm80211/brcmsmac/srom.c | 31 ++++++++++++------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireless/brcm80211/brcmsmac/srom.c b/drivers/net/wireless/brcm80211/brcmsmac/srom.c index 61092156755..56374364303 100644 --- a/drivers/net/wireless/brcm80211/brcmsmac/srom.c +++ b/drivers/net/wireless/brcm80211/brcmsmac/srom.c @@ -763,6 +763,22 @@ _initvars_srom_pci(u8 sromrev, u16 *srom, struct list_head *var_list) } } +/* + * The crc check is done on a little-endian array, we need + * to switch the bytes around before checking crc (and + * then switch it back). + */ +static int do_crc_check(u16 *buf, unsigned nwords) +{ + u8 crc; + + cpu_to_le16_buf(buf, nwords); + crc = crc8(brcms_srom_crc8_table, (void *)buf, nwords << 1, CRC8_INIT_VALUE); + le16_to_cpu_buf(buf, nwords); + + return crc == CRC8_GOOD_VALUE(brcms_srom_crc8_table); +} + /* * Read in and validate sprom. * Return 0 on success, nonzero on error. @@ -772,8 +788,6 @@ sprom_read_pci(struct si_pub *sih, u16 *buf, uint nwords, bool check_crc) { int err = 0; uint i; - u8 *bbuf = (u8 *)buf; /* byte buffer */ - uint nbytes = nwords << 1; struct bcma_device *core; uint sprom_offset; @@ -786,9 +800,9 @@ sprom_read_pci(struct si_pub *sih, u16 *buf, uint nwords, bool check_crc) sprom_offset = CHIPCREGOFFS(sromotp); } - /* read the sprom in bytes */ - for (i = 0; i < nbytes; i++) - bbuf[i] = bcma_read8(core, sprom_offset+i); + /* read the sprom */ + for (i = 0; i < nwords; i++) + buf[i] = bcma_read16(core, sprom_offset+i*2); if (buf[0] == 0xffff) /* @@ -798,13 +812,8 @@ sprom_read_pci(struct si_pub *sih, u16 *buf, uint nwords, bool check_crc) */ return -ENODATA; - if (check_crc && - crc8(brcms_srom_crc8_table, bbuf, nbytes, CRC8_INIT_VALUE) != - CRC8_GOOD_VALUE(brcms_srom_crc8_table)) + if (check_crc && !do_crc_check(buf, nwords)) err = -EIO; - else - /* now correct the endianness of the byte array */ - le16_to_cpu_buf(buf, nwords); return err; } -- 2.20.1