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authorSonic Zhang <sonic.zhang@analog.com>2011-01-11 08:16:43 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2011-02-04 01:44:54 +0300
commit0f66e50af53d39edebf4bc64ef90077e738c171f (patch)
treeb4983675b49343d1e6f7c21352b787168f57eac7 /arch/blackfin
parent3e517f4b1de4787ecff87a73a9865a0b1aa2b10b (diff)
downloadlinux-0f66e50af53d39edebf4bc64ef90077e738c171f.tar.xz
serial: bfin_5xx: split uart RX lock from uart port lock to avoid deadlock
The RX lock is used to protect the RX buffer from concurrent access in DMA mode between the timer and RX interrupt routines. It is independent from the uart lock which is used to protect the TX buffer. It is possible for a uart TX transfer to be started up from the RX interrupt handler if low latency is enabled. So we need to split the locks to avoid deadlocking in this situation. In PIO mode, the RX lock is not necessary because the handle_simple_irq and handle_level_irq functions ensure driver interrupt handlers are called once on one core. And now that the RX path has its own lock, the TX interrupt has nothing to do with the RX path, so disabling it at the same time. Signed-off-by: Sonic Zhang <sonic.zhang@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch/blackfin')
-rw-r--r--arch/blackfin/include/asm/bfin_serial.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/blackfin/include/asm/bfin_serial.h b/arch/blackfin/include/asm/bfin_serial.h
index 1ff9f1468c02..7dbc664eab1e 100644
--- a/arch/blackfin/include/asm/bfin_serial.h
+++ b/arch/blackfin/include/asm/bfin_serial.h
@@ -10,6 +10,7 @@
#define __BFIN_ASM_SERIAL_H__
#include <linux/serial_core.h>
+#include <linux/spinlock.h>
#include <mach/anomaly.h>
#include <mach/bfin_serial.h>
@@ -41,6 +42,7 @@ struct bfin_serial_port {
struct circ_buf rx_dma_buf;
struct timer_list rx_dma_timer;
int rx_dma_nrows;
+ spinlock_t rx_lock;
unsigned int tx_dma_channel;
unsigned int rx_dma_channel;
struct work_struct tx_dma_workqueue;