[PATCH 2/2] 8250_pci Add EEH support to the 8250 driver for IBM/Digi PCIe 2-port Adapter

[PATCH 2/2] 8250_pci Add EEH support to the 8250 driver for IBM/Digi PCIe 2-port Adapter

[Michael Reed]

When working on the 8250_pci driver on PPC, the rmmod command was resulting in a crash when removing the module.  The serial8250_do_pm() is called after the memory are deallocated, meaning that serial8250_set_sleep->serial_outp() will try to write to a
position that is invalid, crashing the system. The purpose of  this patch is to correct that issue.
This patch was created against  2.6.38.6

Patch-created-by:  Breno Leitao <leitao@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Breno Leitao <leitao@linux.vnet.ibm.com>
Cc: Scott Kilau <scottk@digi.com>
Signed-off-by:   Michael Reed <mreed@linux.vnet.ibm.com>
---
 drivers/tty/serial/8250.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index b3b881b..7617cde 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -145,6 +145,8 @@ struct uart_8250_port {
 	unsigned char		mcr_mask;	/* mask of user bits */
 	unsigned char		mcr_force;	/* mask of forced bits */
 	unsigned char		cur_iotype;	/* Running I/O type */
+#define SERIAL8250_DYING 1
+	unsigned char		status;
 
 	/*
 	 * Some bits in registers are cleared on a read, so they must
@@ -2494,7 +2496,8 @@ void serial8250_do_pm(struct uart_port *port, unsigned int state,
 	struct uart_8250_port *p =
 		container_of(port, struct uart_8250_port, port);
 
-	serial8250_set_sleep(p, state != 0);
+	if (!(p->status & SERIAL8250_DYING))
+		serial8250_set_sleep(p, state != 0);
 }
 EXPORT_SYMBOL(serial8250_do_pm);
 
@@ -2588,6 +2591,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up)
 		release_region(up->port.iobase, size);
 		break;
 	}
+	up->status |= SERIAL8250_DYING;
 }
 
 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
-- 
1.7.1

Re: [PATCH 2/2] 8250_pci Add EEH support to the 8250 driver for IBM/Digi PCIe 2-port Adapter

[Greg KH]

On Thu, May 19, 2011 at 02:03:43PM -0500, Michael Reed wrote:
> When working on the 8250_pci driver on PPC, the rmmod command was resulting in a crash when removing the module.  The serial8250_do_pm() is called after the memory are deallocated, meaning that serial8250_set_sleep->serial_outp() will try to write to a
> position that is invalid, crashing the system. The purpose of  this patch is to correct that issue.
> This patch was created against  2.6.38.6
> 
> Patch-created-by:  Breno Leitao <leitao@linux.vnet.ibm.com>
> Cc: Greg Kroah-Hartman <gregkh@suse.de>
> Cc: Breno Leitao <leitao@linux.vnet.ibm.com>
> Cc: Scott Kilau <scottk@digi.com>
> Signed-off-by:   Michael Reed <mreed@linux.vnet.ibm.com>
> ---
>  drivers/tty/serial/8250.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
> index b3b881b..7617cde 100644
> --- a/drivers/tty/serial/8250.c
> +++ b/drivers/tty/serial/8250.c
> @@ -145,6 +145,8 @@ struct uart_8250_port {
>  	unsigned char		mcr_mask;	/* mask of user bits */
>  	unsigned char		mcr_force;	/* mask of forced bits */
>  	unsigned char		cur_iotype;	/* Running I/O type */
> +#define SERIAL8250_DYING 1
> +	unsigned char		status;

Ick, is this really necessary?

A bitfield would be best, only if that is the absolute last way to do
this (and I really think it isn't...)

thanks,

greg k-h

[PATCH] 8250: Fix capabilities when changing the port type

[leitao]

When changing the port type, the capabilities flags should be changed
also, otherwise the capabilities will not correspond to the port type,
which make set_sleep() crash on rmmod.

This patch just assign the correct capabilites when the port changes.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
CC: Michael Reed <mreed@linux.vnet.ibm.com>
---
 drivers/tty/serial/8250.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 6611535..060ce5c 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -3281,7 +3281,7 @@ void serial8250_unregister_port(int line)
 	if (serial8250_isa_devs) {
 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
 		uart->port.type = PORT_UNKNOWN;
-		uart->port.dev = &serial8250_isa_devs->dev;
+		uart->capabilities = uart_config[uart->port.type].flags;
 		uart_add_one_port(&serial8250_reg, &uart->port);
 	} else {
 		uart->port.dev = NULL;
-- 
1.7.1

[PATCH] 8250: Fix capabilities when changing the port type

[leitao]

When changing the port type, the capabilities flags should be changed
also, otherwise the capabilities will not correspond to the port type,
which make set_sleep() crash on rmmod.

This patch just assign the correct capabilites when the port changes.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
CC: Michael Reed <mreed@linux.vnet.ibm.com>
---
 drivers/tty/serial/8250.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index b40f7b9..b4129f5 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -3318,6 +3318,7 @@ void serial8250_unregister_port(int line)
 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
 		uart->port.type = PORT_UNKNOWN;
 		uart->port.dev = &serial8250_isa_devs->dev;
+		uart->capabilities = uart_config[uart->port.type].flags;
 		uart_add_one_port(&serial8250_reg, &uart->port);
 	} else {
 		uart->port.dev = NULL;
-- 
1.7.4.4

[PATCH] 8250_pci Add EEH support to the 8250 driver for IBM/Digi PCIe 2-port Adapter

[mreed]

From: Michael Reed <mreed@linux.vnet.ibm.com>

The purpose of the patch is to add EEH support to the 8250_PCI driver
for the IBM/Digi PCIE 2port Async EIA-232 Adapter that uses a PLX
chipset on the PPC platforrm.  Basic support for this adapter was
recently added https://lkml.org/lkml/2011/5/11/341

This patch was created against the linux-next kernel

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Breno Leitao <leitao@linux.vnet.ibm.com>
Cc: Scott Kilau <scottk@digi.com>
Signed-off-by: Michael Reed <mreed@linux.vnet.ibm.com>
---
 drivers/tty/serial/8250_pci.c |   47 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c
index 4b4968a..5b328e4 100644
--- a/drivers/tty/serial/8250_pci.c
+++ b/drivers/tty/serial/8250_pci.c
@@ -2595,6 +2595,7 @@ pciserial_init_one(struct pci_dev *dev, const struct pci_device_id *ent)
 	board = &pci_boards[ent->driver_data];
 
 	rc = pci_enable_device(dev);
+	pci_save_state(dev);
 	if (rc)
 		return rc;
 
@@ -3868,6 +3869,51 @@ static struct pci_device_id serial_pci_tbl[] = {
 	{ 0, }
 };
 
+static pci_ers_result_t serial8250_io_error_detected(struct pci_dev *dev,
+						pci_channel_state_t state)
+{
+	struct serial_private *priv = pci_get_drvdata(dev);
+
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	if (priv)
+		pciserial_suspend_ports(priv);
+
+	pci_disable_device(dev);
+
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+static pci_ers_result_t serial8250_io_slot_reset(struct pci_dev *dev)
+{
+	int rc;
+
+	rc = pci_enable_device(dev);
+
+	if (rc)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	pci_restore_state(dev);
+	pci_save_state(dev);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void serial8250_io_resume(struct pci_dev *dev)
+{
+	struct serial_private *priv = pci_get_drvdata(dev);
+
+	if (priv)
+		pciserial_resume_ports(priv);
+}
+
+static struct pci_error_handlers serial8250_err_handler = {
+	.error_detected = serial8250_io_error_detected,
+	.slot_reset = serial8250_io_slot_reset,
+	.resume = serial8250_io_resume,
+};
+
 static struct pci_driver serial_pci_driver = {
 	.name		= "serial",
 	.probe		= pciserial_init_one,
@@ -3877,6 +3923,7 @@ static struct pci_driver serial_pci_driver = {
 	.resume		= pciserial_resume_one,
 #endif
 	.id_table	= serial_pci_tbl,
+	.err_handler	= &serial8250_err_handler,
 };
 
 static int __init serial8250_pci_init(void)
-- 
1.7.1