Re: [PATCH net-next 6/7] net/faraday: Fix phy link irq on Aspeed G5 SoCs
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From: Joel Stanley <joel@jms.id.au>
Date: 2016-09-21 02:03:14
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On Wed, Sep 21, 2016 at 12:59 AM, Andrew Lunn [off-list ref] wrote:
On Tue, Sep 20, 2016 at 10:13:14PM +1000, Benjamin Herrenschmidt wrote:quoted
On Tue, 2016-09-20 at 16:00 +0930, Joel Stanley wrote:quoted
On Aspeed SoC with a direct PHY connection (non-NSCI), we receive continual PHYSTS interrupts: [ 20.280000] ftgmac100 1e660000.ethernet eth0: [ISR] = 0x200: PHYSTS_CHG [ 20.280000] ftgmac100 1e660000.ethernet eth0: [ISR] = 0x200: PHYSTS_CHG [ 20.280000] ftgmac100 1e660000.ethernet eth0: [ISR] = 0x200: PHYSTS_CHG [ 20.300000] ftgmac100 1e660000.ethernet eth0: [ISR] = 0x200: PHYSTS_CHG This is because the driver was enabling low-level sensitive interrupt generation where the systems are wired for high-level. All CPU cycles are spent servicing this interrupt.If this is a system wiring issue, should it be represented by a DT property ?Is there a device tree binding document somewhere? Is it possible just to put ACTIVE_HIGH in the right place in the binding?
I wrote "wired for high level" wrt the SoC internals. To be honest I wondered the same thing but it's hard with only one (non-NSCI) system to test on. I had a look at the eval board schematic and it appears that the line has pull down resistors on it, explaining why the IRQ fires when it's configured to active low. Other machines re-use the pin pin as a GPIO. So yes, I will change this to a dt property in v2. That will mean dropping 4/7 "net/faraday: Avoid PHYSTS_CHG interrupt" as well. Cheers, Joel