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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Raviteja Narayanam <raviteja.narayanam@xilinx.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>,
	linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
Subject: [PATCH AUTOSEL 5.7 17/25] i2c: cadence: Clear HOLD bit at correct time in Rx path
Date: Mon, 27 Jul 2020 19:23:37 -0400	[thread overview]
Message-ID: <20200727232345.717432-17-sashal@kernel.org> (raw)
In-Reply-To: <20200727232345.717432-1-sashal@kernel.org>

From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>

[ Upstream commit 12d4d9ec5eeecd712c73772e422b6d082e66b046 ]

There are few issues on Zynq SOC observed in the stress tests causing
timeout errors. Even though all the data is received, timeout error
is thrown. This is due to an IP bug in which the COMP bit in ISR is
not set at end of transfer and completion interrupt is not generated.

This bug is seen on Zynq platforms when the following condition occurs:
Master read & HOLD bit set & Transfer size register reaches '0'.

One workaround is to clear the HOLD bit before the transfer size
register reaches '0'. The current implementation checks for this at
the start of the loop and also only for less than FIFO DEPTH case
(ignoring the equal to case).

So clear the HOLD bit when the data yet to receive is less than or
equal to the FIFO DEPTH. This avoids the IP bug condition.

Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-cadence.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 97a0bd6ea31f1..1efdabb5adca0 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -230,20 +230,21 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 		/* Read data if receive data valid is set */
 		while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
 		       CDNS_I2C_SR_RXDV) {
-			/*
-			 * Clear hold bit that was set for FIFO control if
-			 * RX data left is less than FIFO depth, unless
-			 * repeated start is selected.
-			 */
-			if ((id->recv_count < CDNS_I2C_FIFO_DEPTH) &&
-			    !id->bus_hold_flag)
-				cdns_i2c_clear_bus_hold(id);
-
 			if (id->recv_count > 0) {
 				*(id->p_recv_buf)++ =
 					cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
 				id->recv_count--;
 				id->curr_recv_count--;
+
+				/*
+				 * Clear hold bit that was set for FIFO control
+				 * if RX data left is less than or equal to
+				 * FIFO DEPTH unless repeated start is selected
+				 */
+				if (id->recv_count <= CDNS_I2C_FIFO_DEPTH &&
+				    !id->bus_hold_flag)
+					cdns_i2c_clear_bus_hold(id);
+
 			} else {
 				dev_err(id->adap.dev.parent,
 					"xfer_size reg rollover. xfer aborted!\n");
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Raviteja Narayanam <raviteja.narayanam@xilinx.com>,
	Sasha Levin <sashal@kernel.org>,
	Michal Simek <michal.simek@xilinx.com>,
	Wolfram Sang <wsa@kernel.org>,
	linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.7 17/25] i2c: cadence: Clear HOLD bit at correct time in Rx path
Date: Mon, 27 Jul 2020 19:23:37 -0400	[thread overview]
Message-ID: <20200727232345.717432-17-sashal@kernel.org> (raw)
In-Reply-To: <20200727232345.717432-1-sashal@kernel.org>

From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>

[ Upstream commit 12d4d9ec5eeecd712c73772e422b6d082e66b046 ]

There are few issues on Zynq SOC observed in the stress tests causing
timeout errors. Even though all the data is received, timeout error
is thrown. This is due to an IP bug in which the COMP bit in ISR is
not set at end of transfer and completion interrupt is not generated.

This bug is seen on Zynq platforms when the following condition occurs:
Master read & HOLD bit set & Transfer size register reaches '0'.

One workaround is to clear the HOLD bit before the transfer size
register reaches '0'. The current implementation checks for this at
the start of the loop and also only for less than FIFO DEPTH case
(ignoring the equal to case).

So clear the HOLD bit when the data yet to receive is less than or
equal to the FIFO DEPTH. This avoids the IP bug condition.

Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-cadence.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 97a0bd6ea31f1..1efdabb5adca0 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -230,20 +230,21 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
 		/* Read data if receive data valid is set */
 		while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
 		       CDNS_I2C_SR_RXDV) {
-			/*
-			 * Clear hold bit that was set for FIFO control if
-			 * RX data left is less than FIFO depth, unless
-			 * repeated start is selected.
-			 */
-			if ((id->recv_count < CDNS_I2C_FIFO_DEPTH) &&
-			    !id->bus_hold_flag)
-				cdns_i2c_clear_bus_hold(id);
-
 			if (id->recv_count > 0) {
 				*(id->p_recv_buf)++ =
 					cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
 				id->recv_count--;
 				id->curr_recv_count--;
+
+				/*
+				 * Clear hold bit that was set for FIFO control
+				 * if RX data left is less than or equal to
+				 * FIFO DEPTH unless repeated start is selected
+				 */
+				if (id->recv_count <= CDNS_I2C_FIFO_DEPTH &&
+				    !id->bus_hold_flag)
+					cdns_i2c_clear_bus_hold(id);
+
 			} else {
 				dev_err(id->adap.dev.parent,
 					"xfer_size reg rollover. xfer aborted!\n");
-- 
2.25.1


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  parent reply	other threads:[~2020-07-27 23:29 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 23:23 [PATCH AUTOSEL 5.7 01/25] mt76: mt7615: fix lmac queue debugsfs entry Sasha Levin
2020-07-27 23:23 ` Sasha Levin
2020-07-27 23:23 ` Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 02/25] iwlwifi: fix crash in iwl_dbg_tlv_alloc_trigger Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 03/25] usb: hso: Fix debug compile warning on sparc32 Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 04/25] selftests: fib_nexthop_multiprefix: fix cleanup() netns deletion Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 05/25] qed: Disable "MFW indication via attention" SPAM every 5 minutes Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 06/25] selftests: net: ip_defrag: modprobe missing nf_defrag_ipv6 support Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 07/25] io_uring: always allow drain/link/hardlink/async sqe flags Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 08/25] habanalabs: prevent possible out-of-bounds array access Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 09/25] nfc: s3fwrn5: add missing release on skb in s3fwrn5_recv_frame Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 10/25] scsi: core: Run queue in case of I/O resource contention failure Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 11/25] riscv: kasan: use local_tlb_flush_all() to avoid uninitialized __sbi_rfence Sasha Levin
2020-07-27 23:23   ` Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 12/25] parisc: add support for cmpxchg on u8 pointers Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 13/25] net: ethernet: ravb: exit if re-initialization fails in tx timeout Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 14/25] selftest: txtimestamp: fix net ns entry logic Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 15/25] drivers/net/wan/x25_asy: Fix to make it work Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 16/25] Revert "i2c: cadence: Fix the hold bit setting" Sasha Levin
2020-07-27 23:23   ` Sasha Levin
2020-07-27 23:23 ` Sasha Levin [this message]
2020-07-27 23:23   ` [PATCH AUTOSEL 5.7 17/25] i2c: cadence: Clear HOLD bit at correct time in Rx path Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 18/25] x86/unwind/orc: Fix ORC for newly forked tasks Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 19/25] x86/stacktrace: Fix reliable check for empty user task stacks Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 20/25] cxgb4: add missing release on skb in uld_send() Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 21/25] io_uring: missed req_init_async() for IOSQE_ASYNC Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 22/25] xen-netfront: fix potential deadlock in xennet_remove() Sasha Levin
2020-07-27 23:23   ` Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 23/25] RISC-V: Set maximum number of mapped pages correctly Sasha Levin
2020-07-27 23:23   ` Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 24/25] drivers/net/wan: lapb: Corrected the usage of skb_cow Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 25/25] riscv: Parse all memory blocks to remove unusable memory Sasha Levin
2020-07-27 23:23   ` Sasha Levin

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