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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Robert Hancock <robert.hancock@calian.com>,
	Shubhrajyoti Datta <Shubhrajyoti.datta@amd.com>,
	Michal Simek <michal.simek@amd.com>,
	Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 12/26] i2c: cadence: Change large transfer count reset logic to be unconditional
Date: Wed, 27 Jul 2022 18:10:41 +0200	[thread overview]
Message-ID: <20220727160959.618902682@linuxfoundation.org> (raw)
In-Reply-To: <20220727160959.122591422@linuxfoundation.org>

From: Robert Hancock <robert.hancock@calian.com>

[ Upstream commit 4ca8ca873d454635c20d508261bfc0081af75cf8 ]

Problems were observed on the Xilinx ZynqMP platform with large I2C reads.
When a read of 277 bytes was performed, the controller NAKed the transfer
after only 252 bytes were transferred and returned an ENXIO error on the
transfer.

There is some code in cdns_i2c_master_isr to handle this case by resetting
the transfer count in the controller before it reaches 0, to allow larger
transfers to work, but it was conditional on the CDNS_I2C_BROKEN_HOLD_BIT
quirk being set on the controller, and ZynqMP uses the r1p14 version of
the core where this quirk is not being set. The requirement to do this to
support larger reads seems like an inherently required workaround due to
the core only having an 8-bit transfer size register, so it does not
appear that this should be conditional on the broken HOLD bit quirk which
is used elsewhere in the driver.

Remove the dependency on the CDNS_I2C_BROKEN_HOLD_BIT for this transfer
size reset logic to fix this problem.

Fixes: 63cab195bf49 ("i2c: removed work arounds in i2c driver for Zynq Ultrascale+ MPSoC")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Reviewed-by: Shubhrajyoti Datta <Shubhrajyoti.datta@amd.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-cadence.c | 30 +++++-------------------------
 1 file changed, 5 insertions(+), 25 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 9ab056bb834d..fce1906e7df1 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -203,9 +203,9 @@ static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround)
  */
 static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 {
-	unsigned int isr_status, avail_bytes, updatetx;
+	unsigned int isr_status, avail_bytes;
 	unsigned int bytes_to_send;
-	bool hold_quirk;
+	bool updatetx;
 	struct cdns_i2c *id = ptr;
 	/* Signal completion only after everything is updated */
 	int done_flag = 0;
@@ -224,11 +224,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 	 * Check if transfer size register needs to be updated again for a
 	 * large data receive operation.
 	 */
-	updatetx = 0;
-	if (id->recv_count > id->curr_recv_count)
-		updatetx = 1;
-
-	hold_quirk = (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;
+	updatetx = id->recv_count > id->curr_recv_count;
 
 	/* When receiving, handle data interrupt and completion interrupt */
 	if (id->p_recv_buf &&
@@ -251,7 +247,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 			id->recv_count--;
 			id->curr_recv_count--;
 
-			if (cdns_is_holdquirk(id, hold_quirk))
+			if (cdns_is_holdquirk(id, updatetx))
 				break;
 		}
 
@@ -262,7 +258,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 		 * maintain transfer size non-zero while performing a large
 		 * receive operation.
 		 */
-		if (cdns_is_holdquirk(id, hold_quirk)) {
+		if (cdns_is_holdquirk(id, updatetx)) {
 			/* wait while fifo is full */
 			while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) !=
 			       (id->curr_recv_count - CDNS_I2C_FIFO_DEPTH))
@@ -284,22 +280,6 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 						  CDNS_I2C_XFER_SIZE_OFFSET);
 				id->curr_recv_count = id->recv_count;
 			}
-		} else if (id->recv_count && !hold_quirk &&
-						!id->curr_recv_count) {
-
-			/* Set the slave address in address register*/
-			cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
-						CDNS_I2C_ADDR_OFFSET);
-
-			if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) {
-				cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
-						CDNS_I2C_XFER_SIZE_OFFSET);
-				id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
-			} else {
-				cdns_i2c_writereg(id->recv_count,
-						CDNS_I2C_XFER_SIZE_OFFSET);
-				id->curr_recv_count = id->recv_count;
-			}
 		}
 
 		/* Clear hold (if not repeated start) and signal completion */
-- 
2.35.1




  parent reply	other threads:[~2022-07-27 16:22 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 16:10 [PATCH 4.9 00/26] 4.9.325-rc1 review Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 01/26] security,selinux,smack: kill security_task_wait hook Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 02/26] xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 03/26] misc: rtsx_usb: fix use of dma mapped buffer for usb bulk transfer Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 04/26] misc: rtsx_usb: use separate command and response buffers Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 05/26] misc: rtsx_usb: set return value in rsp_buf alloc err path Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 06/26] xfrm: xfrm_policy: fix a possible double xfrm_pols_put() in xfrm_bundle_lookup() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 07/26] power/reset: arm-versatile: Fix refcount leak in versatile_reboot_probe Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 08/26] perf/core: Fix data race between perf_event_set_output() and perf_mmap_close() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 09/26] ip: Fix a data-race around sysctl_fwmark_reflect Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 10/26] tcp/dccp: Fix a data-race around sysctl_tcp_fwmark_accept Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 11/26] tcp: Fix a data-race around sysctl_tcp_probe_threshold Greg Kroah-Hartman
2022-07-27 16:10 ` Greg Kroah-Hartman [this message]
2022-07-27 16:10 ` [PATCH 4.9 13/26] igmp: Fix data-races around sysctl_igmp_llm_reports Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 14/26] igmp: Fix a data-race around sysctl_igmp_max_memberships Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 15/26] tcp: Fix a data-race around sysctl_tcp_notsent_lowat Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 16/26] be2net: Fix buffer overflow in be_get_module_eeprom Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 17/26] Revert "Revert "char/random: silence a lockdep splat with printk()"" Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 18/26] mm/mempolicy: fix uninit-value in mpol_rebind_policy() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 19/26] bpf: Make sure mac_header was set before using it Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 20/26] ALSA: memalloc: Align buffer allocations in page size Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 21/26] tty: drivers/tty/, stop using tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 22/26] tty: the rest, " Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 23/26] tty: drop tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 24/26] tty: extract tty_flip_buffer_commit() from tty_flip_buffer_push() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 25/26] tty: use new tty_insert_flip_string_and_push_buffer() in pty_write() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.9 26/26] net: usb: ax88179_178a needs FLAG_SEND_ZLP Greg Kroah-Hartman
2022-07-27 22:18 ` [PATCH 4.9 00/26] 4.9.325-rc1 review Florian Fainelli
2022-07-28  9:42 ` Pavel Machek
2022-07-28 10:08 ` Naresh Kamboju
2022-07-28 14:32 ` Jon Hunter
2022-07-28 14:52 ` Shuah Khan
2022-07-28 22:57 ` Guenter Roeck

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