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From: Ray Jui <ray.jui@broadcom.com>
To: Dhananjay Phadke <dphadke@linux.microsoft.com>,
	rayagonda.kokatanur@broadcom.com
Cc: andriy.shevchenko@linux.intel.com,
	bcm-kernel-feedback-list@broadcom.com, brendanhiggins@google.com,
	f.fainelli@gmail.com, linux-arm-kernel@lists.infradead.org,
	linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	lori.hikichi@broadcom.com, rjui@broadcom.com,
	sbranden@broadcom.com, wsa@kernel.org
Subject: Re: [PATCH v1 6/6] i2c: iproc: handle rx fifo full interrupt
Date: Fri, 23 Oct 2020 10:42:04 -0700	[thread overview]
Message-ID: <e9d15e5a-e868-baff-177f-81aa1d742ff1@broadcom.com> (raw)
In-Reply-To: <20201011182254.17776-7-rayagonda.kokatanur@broadcom.com>

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On 10/12/2020 3:03 PM, Dhananjay Phadke wrote:
> From: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
> 
> On Sun, 11 Oct 2020 23:52:54 +0530, Rayagonda Kokatanur wrote:
>> Add code to handle IS_S_RX_FIFO_FULL_SHIFT interrupt to support
>> master write request with >= 64 bytes.
>>
>> Iproc has a slave rx fifo size of 64 bytes.
>> Rx fifo full interrupt (IS_S_RX_FIFO_FULL_SHIFT) will be generated
>> when RX fifo becomes full. This can happen if master issues write
>> request of more than 64 bytes.
>>
> 
> ARM cores run much faster than I2C bus, why would rx fifo go full when
> rx interrupt is enabled and bytes are read out by bus driver isr?
> Isn't fifo read pointer updated on these byte reads?

Hi Rayagonda,

Could you please reply on this question? For transactions > 64 bytes, do
we batch until RX FIFO is full before we read out the data?

Thanks,

Ray

> Does controller stretch clock when rx fifo is full (e.g. kernel has
> crashed, bus driver isn't draining fifo)?
> 

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  parent reply	other threads:[~2020-10-23 17:42 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-11 18:22 [PATCH v1 0/6] fix iproc driver to handle master read request Rayagonda Kokatanur
2020-10-11 18:22 ` [PATCH v1 1/6] i2c: iproc: handle Master aborted error Rayagonda Kokatanur
2020-10-23 17:14   ` Ray Jui
2020-10-11 18:22 ` [PATCH v1 2/6] i2c: iproc: handle only slave interrupts which are enabled Rayagonda Kokatanur
2020-10-23 17:18   ` Ray Jui
2020-10-11 18:22 ` [PATCH v1 3/6] i2c: iproc: update slave isr mask (ISR_MASK_SLAVE) Rayagonda Kokatanur
2020-10-23 17:19   ` Ray Jui
2020-10-11 18:22 ` [PATCH v1 4/6] i2c: iproc: fix typo in slave_isr function Rayagonda Kokatanur
2020-10-23 17:20   ` Ray Jui
2020-10-26 13:52     ` Rayagonda Kokatanur
2020-10-11 18:22 ` [PATCH v1 5/6] i2c: iproc: handle master read request Rayagonda Kokatanur
2020-10-14  3:20   ` Dhananjay Phadke
2020-10-14  9:12     ` Rayagonda Kokatanur
     [not found]     ` <CAHO=5PEtoJrFEPin0hH19Ubs9Zmhxiay4jSGAhXBFE=ft=+CYg@mail.gmail.com>
2020-10-23 17:26       ` Ray Jui
2020-10-26 13:55         ` Rayagonda Kokatanur
2020-10-11 18:22 ` [PATCH v1 6/6] i2c: iproc: handle rx fifo full interrupt Rayagonda Kokatanur
2020-10-12 22:03   ` Dhananjay Phadke
2020-10-23 17:42   ` Ray Jui [this message]
2020-10-26 15:13     ` Rayagonda Kokatanur
2020-10-27  0:36       ` Ray Jui

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