MIPS: OCTEON: Add semaphore to serialize bootbus accesses.

Some hardware blocks attached to the OCTEON bootbus run asynchronously
to accesses from the CPUs.  These include MMC/SD host, CF(when using
DMA), and NAND controller.  A bus error, or corrupt data may occur if
a CPU is trying to access a bootbus connected device at the same time
the bus is running asynchronous operations.

To work around these problems we add this semaphore that must be
acquired before initiating bootbus activity.  Subsequent patches will
add users for this.

Signed-off-by: David Daney <david.daney@cavium.com>
[aleksey.makarov@auriga.com: combine the patches]
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Signed-off-by: Chandrakala Chavva <cchavva@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9459/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index a42110e7edbcabefdea9a011de9e032f88388a87..01130e93126deb087ccc0da3cad9bf18256eea00 100644 (file)
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -51,6 +51,9 @@ extern void pci_console_init(const char *arg);
 
 static unsigned long long MAX_MEMORY = 512ull << 20;
 
+DEFINE_SEMAPHORE(octeon_bootbus_sem);
+EXPORT_SYMBOL(octeon_bootbus_sem);
+
 struct octeon_boot_descriptor *octeon_boot_desc_ptr;
 
 struct cvmx_bootinfo *octeon_bootinfo;

diff --git a/arch/mips/include/asm/octeon/octeon.h b/arch/mips/include/asm/octeon/octeon.h
index 0415965708565c7ddf8d5fe3451f67e907ce9a9c..de9f74ee5dd0d2ace8165085918ea49d38f6242d 100644 (file)
--- a/arch/mips/include/asm/octeon/octeon.h
+++ b/arch/mips/include/asm/octeon/octeon.h
@@ -335,4 +335,6 @@ void octeon_irq_set_ip4_handler(octeon_irq_ip4_handler_t);
 
 extern void octeon_fixup_irqs(void);
 
+extern struct semaphore octeon_bootbus_sem;
+
 #endif /* __ASM_OCTEON_OCTEON_H */