From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: [PATCH v3 1/2] serial/8250_pci: setup-quirk workaround for the kt serial controller Date: Tue, 22 Nov 2011 13:41:24 -0800 Message-ID: <20111122214124.13786.20202.stgit@localhost6.localdomain6> References: <20111122213859.13786.7738.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20111122213859.13786.7738.stgit@localhost6.localdomain6> Sender: linux-kernel-owner@vger.kernel.org To: gregkh@suse.de Cc: Nhan H Mai , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, alan@linux.intel.com List-Id: linux-serial@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 | 4 +++- drivers/tty/serial/8250_pci.c | 17 ++++++++++++++++- include/linux/serial_core.h | 1 + 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c index eeadf1b..3a8e5bf 100644 --- a/drivers/tty/serial/8250.c +++ b/drivers/tty/serial/8250.c @@ -1619,11 +1619,13 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) do { struct uart_8250_port *up; struct uart_port *port; + bool skip; up = list_entry(l, struct uart_8250_port, list); port = &up->port; + skip = pass_counter && up->port.flags & UPF_IIR_ONCE; - if (port->handle_irq(port)) { + if (!skip && port->handle_irq(port)) { handled = 1; end = NULL; } else if (end == NULL) diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c index 825937a..8742ef5 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) @@ -1110,7 +1118,6 @@ pci_xr17c154_setup(struct serial_private *priv, return pci_default_setup(priv, board, port, idx); } -/* This should be in linux/pci_ids.h */ #define PCI_VENDOR_ID_SBSMODULARIO 0x124B #define PCI_SUBVENDOR_ID_SBSMODULARIO 0x124B #define PCI_DEVICE_ID_OCTPRO 0x0001 @@ -1136,6 +1143,7 @@ pci_xr17c154_setup(struct serial_private *priv, #define PCI_DEVICE_ID_OXSEMI_16PCI958 0x9538 #define PCIE_DEVICE_ID_NEO_2_OX_IBM 0x00F6 #define PCI_DEVICE_ID_PLX_CRONYX_OMEGA 0xc001 +#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d /* Unknown vendors/cards - this should not be in linux/pci_ids.h */ #define PCI_SUBDEVICE_ID_UNKNOWN_0x1584 0x1584 @@ -1220,6 +1228,13 @@ 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/serial_core.h b/include/linux/serial_core.h index 945e02c..b67305e 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -351,6 +351,7 @@ struct uart_port { #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) #define UPF_EXAR_EFR ((__force upf_t) (1 << 25)) +#define UPF_IIR_ONCE ((__force upf_t) (1 << 26)) /* 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))