On Fri, 2015-10-23 at 06:01 -0500, Hou Zhiqiang-B48286 wrote:
-----Original Message----- From: Wood Scott-B07421 Sent: 2015年10月23日 7:11 To: Gong Qianyu-B52263 Cc: u-boot@lists.denx.de; Hu Mingkai-B21284; Sun York-R58495; Hou Zhiqiang-B48286; Xie Shaohui-B21989; Song Wenbin-B53747; Wood Scott- B07421; Kushwaha Prabhakar-B32579; Wang Huan-B18965 Subject: Re: [Patch V7 04/18] net/fm/eth: Use mb() to be compatible for both ARM and PowerPC
On Thu, 2015-10-22 at 18:46 +0800, Gong Qianyu wrote:
From: Shaohui Xie Shaohui.Xie@freescale.com
Use mb() instead of sync() to be compatible for both ARM and PowerPC.
Signed-off-by: Shaohui Xie Shaohui.Xie@freescale.com Signed-off-by: Mingkai Hu Mingkai.Hu@freescale.com Signed-off-by: Gong Qianyu Qianyu.Gong@freescale.com
V7:
- No change.
V6:
- No change.
V5:
- No change.
V4:
- No change.
V3:
- New patch. Separated from patch 'net: Move some header files to
include/'
drivers/net/fm/eth.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/net/fm/eth.c b/drivers/net/fm/eth.c index 368d554..ad02c66 100644 --- a/drivers/net/fm/eth.c +++ b/drivers/net/fm/eth.c @@ -371,7 +371,7 @@ static void fmc_tx_port_graceful_stop_enable(struct fm_eth *fm_eth) pram = fm_eth->tx_pram; /* graceful stop transmission of frames */ setbits_be32(&pram->mode, PRAM_MODE_GRACEFUL_STOP);
sync();
mb();}
static void fmc_tx_port_graceful_stop_disable(struct fm_eth *fm_eth) @@ -381,7 +381,7 @@ static void fmc_tx_port_graceful_stop_disable(struct fm_eth *fm_eth) pram = fm_eth->tx_pram; /* re-enable transmission of frames */ clrbits_be32(&pram->mode, PRAM_MODE_GRACEFUL_STOP);
sync();
mb();}
Why is it needed at all? The I/O accessors should include the necessary barriers.
The I/O accessors of powerpc does include the barrier, but it absents from ARMs'.
Then fix ARM's accessors if they're missing barriers that are required. But first, consider whether the barrier is required on ARM. What is special about FM that it needs it where all other drivers don't?
-Scott