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* [PATCH AUTOSEL 5.4 01/33] i2c: rcar: faster irq code to minimize HW race condition
@ 2021-03-02 11:57 Sasha Levin
  2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 02/33] i2c: rcar: optimize cacheline " Sasha Levin
                   ` (31 more replies)
  0 siblings, 32 replies; 48+ messages in thread
From: Sasha Levin @ 2021-03-02 11:57 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Wolfram Sang, Niklas Söderlund, Wolfram Sang, Sasha Levin,
	linux-i2c

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

[ Upstream commit c7b514ec979e23a08c411f3d8ed39c7922751422 ]

To avoid the HW race condition on R-Car Gen2 and earlier, we need to
write to ICMCR as soon as possible in the interrupt handler. We can
improve this by writing a static value instead of masking out bits.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-rcar.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 9c162a01a584..9d54ae935524 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -89,7 +89,6 @@
 
 #define RCAR_BUS_PHASE_START	(MDBS | MIE | ESG)
 #define RCAR_BUS_PHASE_DATA	(MDBS | MIE)
-#define RCAR_BUS_MASK_DATA	(~(ESG | FSB) & 0xFF)
 #define RCAR_BUS_PHASE_STOP	(MDBS | MIE | FSB)
 
 #define RCAR_IRQ_SEND	(MNR | MAL | MST | MAT | MDE)
@@ -616,7 +615,7 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
 /*
  * This driver has a lock-free design because there are IP cores (at least
  * R-Car Gen2) which have an inherent race condition in their hardware design.
- * There, we need to clear RCAR_BUS_MASK_DATA bits as soon as possible after
+ * There, we need to switch to RCAR_BUS_PHASE_DATA as soon as possible after
  * the interrupt was generated, otherwise an unwanted repeated message gets
  * generated. It turned out that taking a spinlock at the beginning of the ISR
  * was already causing repeated messages. Thus, this driver was converted to
@@ -625,13 +624,11 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
 static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
 {
 	struct rcar_i2c_priv *priv = ptr;
-	u32 msr, val;
+	u32 msr;
 
 	/* Clear START or STOP immediately, except for REPSTART after read */
-	if (likely(!(priv->flags & ID_P_REP_AFTER_RD))) {
-		val = rcar_i2c_read(priv, ICMCR);
-		rcar_i2c_write(priv, ICMCR, val & RCAR_BUS_MASK_DATA);
-	}
+	if (likely(!(priv->flags & ID_P_REP_AFTER_RD)))
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
 
 	msr = rcar_i2c_read(priv, ICMSR);
 
-- 
2.30.1


^ permalink raw reply related	[flat|nested] 48+ messages in thread

end of thread, other threads:[~2021-03-03 19:44 UTC | newest]

Thread overview: 48+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-02 11:57 [PATCH AUTOSEL 5.4 01/33] i2c: rcar: faster irq code to minimize HW race condition Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 02/33] i2c: rcar: optimize cacheline " Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 03/33] udf: fix silent AED tagLocation corruption Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 04/33] mmc: mxs-mmc: Fix a resource leak in an error handling path in 'mxs_mmc_probe()' Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 05/33] mmc: sdhci-of-dwcmshc: set SDHCI_QUIRK2_PRESET_VALUE_BROKEN Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 06/33] mmc: mediatek: fix race condition between msdc_request_timeout and irq Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 07/33] Platform: OLPC: Fix probe error handling Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 08/33] powerpc/pci: Add ppc_md.discover_phbs() Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 09/33] HID: i2c-hid: Add I2C_HID_QUIRK_NO_IRQ_AFTER_RESET for ITE8568 EC on Voyo Winpad A15 Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 10/33] spi: stm32: make spurious and overrun interrupts visible Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 11/33] powerpc: improve handling of unrecoverable system reset Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 12/33] powerpc/perf: Record counter overflow always if SAMPLE_IP is unset Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 13/33] HID: logitech-dj: add support for the new lightspeed connection iteration Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 14/33] powerpc/64: Fix stack trace not displaying final frame Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 15/33] iommu/amd: Fix performance counter initialization Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 16/33] sparc32: Limit memblock allocation to low memory Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 17/33] sparc64: Use arch_validate_flags() to validate ADI flag Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 18/33] ACPICA: Fix race in generic_serial_bus (I2C) and GPIO op_region parameter handling Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 19/33] Input: applespi - don't wait for responses to commands indefinitely Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 20/33] x86, build: use objtool mcount Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 21/33] PCI: xgene-msi: Fix race in installing chained irq handler Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 22/33] misc: eeprom_93xx46: Add quirk to support Microchip 93LC46B eeprom Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 23/33] PCI: mediatek: Add missing of_node_put() to fix reference leak Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 24/33] drm/msm/a5xx: Remove overwriting A5XX_PC_DBG_ECO_CNTL register Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 25/33] kbuild: clamp SUBLEVEL to 255 Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 26/33] PCI: Fix pci_register_io_range() memory leak Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 27/33] i40e: Fix memory leak in i40e_probe Sasha Levin
2021-03-02 11:57   ` [Intel-wired-lan] " Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 28/33] s390/smp: __smp_rescan_cpus() - move cpumask away from stack Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 29/33] sysctl.c: fix underflow value setting risk in vm_table Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 30/33] scsi: libiscsi: Fix iscsi_prep_scsi_cmd_pdu() error handling Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 31/33] nbd: handle device refs for DESTROY_ON_DISCONNECT properly Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 32/33] scsi: target: core: Add cmd length set before cmd complete Sasha Levin
2021-03-02 11:57   ` Sasha Levin
2021-03-02 11:57 ` [PATCH AUTOSEL 5.4 33/33] scsi: target: core: Prevent underflow for service actions Sasha Levin

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