Move INT0 clearing out of common, per-port serial8250_do_startup()
into PCI device probe/resume.
As described in commit 2c0ac5b48a35 ("serial: exar: Fix stuck MSIs"),
the purpose of clearing INT0 is to prevent the PCI interrupt line from
becoming stuck asserted, "which is fatal with edge-triggered MSIs".
Like the clearing via interrupt handler that moved from common code in
commit c7e1b4059075 ("tty: serial: exar: Relocate sleep wake-up
handling"), this clearing at startup can be better handled at the PCI
device level.
Cc: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Cc: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Aaron Sierra <asierra@xxxxxxxxxxx>
---
The only difference from v1 is that this version is rebased onto tty-testing.
The embedded patch was tested on top of 21176ebcd7d0 ("serial: sh-sci: Use
DEVICE_ATTR_RW() for rx_fifo_trigger").
drivers/tty/serial/8250/8250_exar.c | 24 ++++++++++++++++--------
drivers/tty/serial/8250/8250_port.c | 9 ---------
2 files changed, 16 insertions(+), 17 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 357e20a6566f..3e93bd2326c9 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -493,6 +493,16 @@ static void pci_xr17v35x_exit(struct pci_dev *pcidev)
port->port.private_data = NULL;
}
+static inline void exar_misc_clear(struct exar8250 *priv)
+{
+ /* Clear all PCI interrupts by reading INT0. No effect on IIR */
+ readb(priv->virt + UART_EXAR_INT0);
+
+ /* Clear INT0 for Expansion Interface slave ports, too */
+ if (priv->board->num_ports > 8)
+ readb(priv->virt + 0x2000 + UART_EXAR_INT0);
+}
+
/*
* These Exar UARTs have an extra interrupt indicator that could fire for a
* few interrupts that are not presented/cleared through IIR. One of which is
@@ -504,14 +514,7 @@ static void pci_xr17v35x_exit(struct pci_dev *pcidev)
*/
static irqreturn_t exar_misc_handler(int irq, void *data)
{
- struct exar8250 *priv = data;
-
- /* Clear all PCI interrupts by reading INT0. No effect on IIR */
- readb(priv->virt + UART_EXAR_INT0);
-
- /* Clear INT0 for Expansion Interface slave ports, too */
- if (priv->board->num_ports > 8)
- readb(priv->virt + 0x2000 + UART_EXAR_INT0);
+ exar_misc_clear(data);
return IRQ_HANDLED;
}
@@ -584,6 +587,9 @@ exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
if (rc)
return rc;
+ /* Clear interrupts */
+ exar_misc_clear(priv);
+
for (i = 0; i < nr_ports && i < maxnr; i++) {
rc = board->setup(priv, pcidev, &uart, i);
if (rc) {
@@ -642,6 +648,8 @@ static int __maybe_unused exar_resume(struct device *dev)
struct exar8250 *priv = dev_get_drvdata(dev);
unsigned int i;
+ exar_misc_clear(priv);
+
for (i = 0; i < priv->nr; i++)
if (priv->line[i] >= 0)
serial8250_resume_port(priv->line[i]);
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 995a7e8b7839..706645f89132 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -40,11 +40,6 @@
#include "8250.h"
-/*
- * These are definitions for the Exar XR17V35X and XR17(C|D)15X
- */
-#define UART_EXAR_INT0 0x80
-
/* Nuvoton NPCM timeout register */
#define UART_NPCM_TOR 7
#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
@@ -2138,8 +2133,6 @@ int serial8250_do_startup(struct uart_port *port)
serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
- if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
- serial_port_in(port, UART_EXAR_INT0);
/*
* At this point, there's no way the LSR could still be 0xff;
@@ -2297,8 +2290,6 @@ int serial8250_do_startup(struct uart_port *port)
serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
- if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
- serial_port_in(port, UART_EXAR_INT0);
up->lsr_saved_flags = 0;
up->msr_saved_flags = 0;
--
2.17.1
