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authorStefan Richter <stefanr@s5r6.in-berlin.de>2011-06-21 15:24:26 +0200
committerStefan Richter <stefanr@s5r6.in-berlin.de>2011-07-09 17:12:08 +0200
commitb14c369d87d7fbf120ad21919d34a8f1290290f1 (patch)
tree37947e2121f1c205ee4295c8c8c559d9f7693f87 /drivers/firewire
parent9ef28ccd59a23d219c4660f55a11ac06ca91f632 (diff)
downloadop-kernel-dev-b14c369d87d7fbf120ad21919d34a8f1290290f1.zip
op-kernel-dev-b14c369d87d7fbf120ad21919d34a8f1290290f1.tar.gz
firewire: ohci: add a comment on PHY reg access serialization
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/ohci.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 3b6f342..a818dc8 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -513,6 +513,12 @@ static inline void flush_writes(const struct fw_ohci *ohci)
reg_read(ohci, OHCI1394_Version);
}
+/*
+ * Beware! read_phy_reg(), write_phy_reg(), update_phy_reg(), and
+ * read_paged_phy_reg() require the caller to hold ohci->phy_reg_mutex.
+ * In other words, only use ohci_read_phy_reg() and ohci_update_phy_reg()
+ * directly. Exceptions are intrinsically serialized contexts like pci_probe.
+ */
static int read_phy_reg(struct fw_ohci *ohci, int addr)
{
u32 val;
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