linux-kernel - [PATCH v3 1/4] tpm: Use a threaded interrupt handler

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Message-Id: <20210501135727.17747-2-LinoSanfilippo@gmx.de>
Date:   Sat,  1 May 2021 15:57:24 +0200
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     peterhuewe@....de, jarkko@...nel.org, jgg@...pe.ca
Cc:     stefanb@...ux.vnet.ibm.com, James.Bottomley@...senpartnership.com,
        keescook@...omium.org, jsnitsel@...hat.com, ml.linux@...oe.vision,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        LinoSanfilippo@....de, Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH v3 1/4] tpm: Use a threaded interrupt handler

The interrupt handler uses tpm_tis_read32() and tpm_tis_write32() to access
the interrupt status register. In case of SPI those accesses are done with
the spi_bus_lock mutex held. This means that the status register cannot
be read or written in interrupt context.

For this reason request a threaded interrupt handler so that the required
accesses can be done in process context.

Reviewed-by: Stefan Berger <stefanb@...ux.ibm.com>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....de>
---
 drivers/char/tpm/tpm_tis_core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index a2e0395cbe61..a12992ae2a3e 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -737,8 +737,10 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 	int rc;
 	u32 int_status;
 
-	if (devm_request_irq(chip->dev.parent, irq, tis_int_handler, flags,
-			     dev_name(&chip->dev), chip) != 0) {
+
+	if (devm_request_threaded_irq(chip->dev.parent, irq, NULL,
+				      tis_int_handler, IRQF_ONESHOT | flags,
+				      dev_name(&chip->dev), chip) != 0) {
 		dev_info(&chip->dev, "Unable to request irq: %d for probe\n",
 			 irq);
 		return -1;
-- 
2.31.1