From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752436Ab1JWW1T (ORCPT ); Sun, 23 Oct 2011 18:27:19 -0400 Received: from mga01.intel.com ([192.55.52.88]:54686 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752198Ab1JWW1R (ORCPT ); Sun, 23 Oct 2011 18:27:17 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.69,395,1315206000"; d="scan'208";a="80960236" Subject: [PATCH] serial/8250_pci: add a quirk for the kt serial controller To: gregkh@suse.de From: Dan Williams Cc: Nhan H Mai , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, alan@linux.intel.com Date: Sun, 23 Oct 2011 15:27:16 -0700 Message-ID: <20111023222711.22713.11434.stgit@localhost6.localdomain6> User-Agent: StGit/0.15-7-g9bfb-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Workaround dropped notifications in the iir register. Prevent reads coincident with new interrupt notifications by reading the iir at most once per interrupt. Reported-by: Nhan H Mai Signed-off-by: Dan Williams --- drivers/tty/serial/8250.c | 6 +++++- drivers/tty/serial/8250_pci.c | 15 +++++++++++++++ include/linux/pci_ids.h | 1 + include/linux/serial_core.h | 1 + 4 files changed, 22 insertions(+), 1 deletions(-) diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c index 7f50999..513e728 100644 --- a/drivers/tty/serial/8250.c +++ b/drivers/tty/serial/8250.c @@ -1652,7 +1652,11 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) up = list_entry(l, struct uart_8250_port, list); - iir = serial_in(up, UART_IIR); + if (pass_counter && up->port.flags & UPF_IIR_ONCE) + iir = UART_IIR_NO_INT; + else + iir = serial_in(up, UART_IIR); + if (!(iir & UART_IIR_NO_INT)) { serial8250_handle_port(up); diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c index 3abeca2..4ad2fb4 100644 --- a/drivers/tty/serial/8250_pci.c +++ b/drivers/tty/serial/8250_pci.c @@ -1092,6 +1092,14 @@ static int skip_tx_en_setup(struct serial_private *priv, return pci_default_setup(priv, board, port, idx); } +static int kt_serial_setup(struct serial_private *priv, + const struct pciserial_board *board, + struct uart_port *port, int idx) +{ + port->flags |= UPF_IIR_ONCE; + return skip_tx_en_setup(priv, board, port, idx); +} + static int pci_eg20t_init(struct pci_dev *dev) { #if defined(CONFIG_SERIAL_PCH_UART) || defined(CONFIG_SERIAL_PCH_UART_MODULE) @@ -1211,6 +1219,13 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { .subdevice = PCI_ANY_ID, .setup = ce4100_serial_setup, }, + { + .vendor = PCI_VENDOR_ID_INTEL, + .device = PCI_DEVICE_ID_INTEL_PATSBURG_KT, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = kt_serial_setup, + }, /* * ITE */ diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h index ae96bbe..ed80d75 100644 --- a/include/linux/pci_ids.h +++ b/include/linux/pci_ids.h @@ -2492,6 +2492,7 @@ #define PCI_DEVICE_ID_INTEL_IOAT 0x1a38 #define PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MIN 0x1c41 #define PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MAX 0x1c5f +#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d #define PCI_DEVICE_ID_INTEL_PATSBURG_LPC_0 0x1d40 #define PCI_DEVICE_ID_INTEL_PATSBURG_LPC_1 0x1d41 #define PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI 0x1e31 diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index a5c3114..a66484b3 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -350,6 +350,7 @@ struct uart_port { #define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16)) #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) +#define UPF_IIR_ONCE ((__force upf_t) (1 << 25)) /* The exact UART type is known and should not be probed. */ #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27)) #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))