Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751994AbbEFVgw (ORCPT ); Wed, 6 May 2015 17:36:52 -0400 Received: from mail-by2on0131.outbound.protection.outlook.com ([207.46.100.131]:26558 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751872AbbEFVgs (ORCPT ); Wed, 6 May 2015 17:36:48 -0400 Authentication-Results: spf=fail (sender IP is 192.88.168.50) smtp.mailfrom=freescale.com; freescale.mail.onmicrosoft.com; dkim=none (message not signed) header.d=none; From: "J. German Rivera" To: , , , CC: , , , , , , , , , "J. German Rivera" Subject: [PATCH v2 6/7] staging: fsl-mc: Add locking to serialize mc_send_command() calls Date: Wed, 6 May 2015 16:28:27 -0500 Message-ID: <1430947708-10521-7-git-send-email-German.Rivera@freescale.com> X-Mailer: git-send-email 2.3.3 In-Reply-To: <1430947708-10521-1-git-send-email-German.Rivera@freescale.com> References: <1430947708-10521-1-git-send-email-German.Rivera@freescale.com> X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:192.88.168.50;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10019020)(6009001)(339900001)(189002)(199003)(50466002)(92566002)(105606002)(36756003)(229853001)(19580405001)(86362001)(19580395003)(189998001)(48376002)(76176999)(46102003)(106466001)(85426001)(50226001)(6806004)(5001960100002)(2950100001)(104016003)(47776003)(50986999)(5001770100001)(107886002)(77156002)(77096005)(62966003)(87936001)(2201001)(4001430100001);DIR:OUT;SFP:1102;SCL:1;SRVR:DM2PR03MB509;H:tx30smr01.am.freescale.net;FPR:;SPF:Fail;MLV:sfv;MX:1;A:1;LANG:en; MIME-Version: 1.0 Content-Type: text/plain X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:DM2PR03MB509; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(5005006)(3002001);SRVR:DM2PR03MB509;BCL:0;PCL:0;RULEID:;SRVR:DM2PR03MB509; X-Forefront-PRVS: 0568F32D91 X-OriginatorOrg: freescale.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 May 2015 21:36:44.6047 (UTC) X-MS-Exchange-CrossTenant-Id: 710a03f5-10f6-4d38-9ff4-a80b81da590d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=710a03f5-10f6-4d38-9ff4-a80b81da590d;Ip=[192.88.168.50];Helo=[tx30smr01.am.freescale.net] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM2PR03MB509 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6863 Lines: 192 Add a locking mechanism to serialize mc_send_command() calls that use the same fsl_mc_io object (same MC portal). When the fsl_mc_io object is created the owner needs to know in which type of context the fsl_mc_io object is going to be used. A flag passed-in to fsl_create_mc_io() will indicate whether the fsl_mc_io object will be used in atomic or non-atomic context. If the fsl_mc_io object is going to be used in non-atomic context only, mc_send_command() calls with it will be serialized using a mutex. Otherwise, if the fsl_mc_io object is going to be used in atomic context, mc_semd_command() calls with it will be serialized using a spinlock. Signed-off-by: J. German Rivera Reviewed-by: Stuart Yoder --- Changes in v2: - Relaxed rules for FSL_MC_IO_ATOMIC_CONTEXT_PORTAL. Some drivers (e.g., DPNI) need to send MC commands with the same mc_io object, from both atomic and non-atomic context. So, we need to relax the rules to use mc_io objects created with the FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag on, to allow this. - Use msecs_to_jiffies() instead of HZ in timeout-related expression drivers/staging/fsl-mc/bus/dprc-driver.c | 6 ++--- drivers/staging/fsl-mc/bus/mc-sys.c | 40 +++++++++++++++++++++++++------- drivers/staging/fsl-mc/include/mc-sys.h | 23 ++++++++++++++++-- 3 files changed, 55 insertions(+), 14 deletions(-) diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c b/drivers/staging/fsl-mc/bus/dprc-driver.c index 72eacee..5e24f46 100644 --- a/drivers/staging/fsl-mc/bus/dprc-driver.c +++ b/drivers/staging/fsl-mc/bus/dprc-driver.c @@ -502,10 +502,8 @@ static int register_dprc_irq_handlers(struct fsl_mc_device *mc_dev) for (i = 0; i < ARRAY_SIZE(irq_handlers); i++) { irq = mc_dev->irqs[i]; - if (WARN_ON(irq->dev_irq_index != i)) { - error = -EINVAL; - goto error_unregister_irq_handlers; - } + if (WARN_ON(irq->dev_irq_index != i)) + return -EINVAL; /* * NOTE: Normally, devm_request_threaded_irq() programs the MSI diff --git a/drivers/staging/fsl-mc/bus/mc-sys.c b/drivers/staging/fsl-mc/bus/mc-sys.c index 9ae000c..2b3d18c 100644 --- a/drivers/staging/fsl-mc/bus/mc-sys.c +++ b/drivers/staging/fsl-mc/bus/mc-sys.c @@ -40,9 +40,9 @@ #include /** - * Timeout in jiffies to wait for the completion of an MC command + * Timeout in milliseconds to wait for the completion of an MC command */ -#define MC_CMD_COMPLETION_TIMEOUT_JIFFIES (HZ / 2) /* 500 ms */ +#define MC_CMD_COMPLETION_TIMEOUT_MS 500 /* * usleep_range() min and max values used to throttle down polling @@ -86,6 +86,11 @@ int __must_check fsl_create_mc_io(struct device *dev, mc_io->portal_phys_addr = mc_portal_phys_addr; mc_io->portal_size = mc_portal_size; mc_io->resource = resource; + if (flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL) + spin_lock_init(&mc_io->spinlock); + else + mutex_init(&mc_io->mutex); + res = devm_request_mem_region(dev, mc_portal_phys_addr, mc_portal_size, @@ -230,14 +235,21 @@ static inline enum mc_cmd_status mc_read_response(struct mc_command __iomem * * @cmd: command to be sent * * Returns '0' on Success; Error code otherwise. - * - * NOTE: This function cannot be invoked from from atomic contexts. */ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) { + int error; enum mc_cmd_status status; unsigned long jiffies_until_timeout = - jiffies + MC_CMD_COMPLETION_TIMEOUT_JIFFIES; + jiffies + msecs_to_jiffies(MC_CMD_COMPLETION_TIMEOUT_MS); + + if (WARN_ON(in_irq())) + return -EINVAL; + + if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL) + spin_lock(&mc_io->spinlock); + else + mutex_lock(&mc_io->mutex); /* * Send command to the MC hardware: @@ -259,6 +271,8 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) if (preemptible()) { usleep_range(MC_CMD_COMPLETION_POLLING_MIN_SLEEP_USECS, MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS); + } else { + udelay(MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS); } if (time_after_eq(jiffies, jiffies_until_timeout)) { @@ -269,7 +283,8 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) (unsigned int) MC_CMD_HDR_READ_CMDID(cmd->header)); - return -ETIMEDOUT; + error = -ETIMEDOUT; + goto common_exit; } } @@ -281,9 +296,18 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) mc_status_to_string(status), (unsigned int)status); - return mc_status_to_error(status); + error = mc_status_to_error(status); + goto common_exit; } - return 0; + error = 0; + +common_exit: + if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL) + spin_unlock(&mc_io->spinlock); + else + mutex_unlock(&mc_io->mutex); + + return error; } EXPORT_SYMBOL(mc_send_command); diff --git a/drivers/staging/fsl-mc/include/mc-sys.h b/drivers/staging/fsl-mc/include/mc-sys.h index cb3b5a2..7ea12a6 100644 --- a/drivers/staging/fsl-mc/include/mc-sys.h +++ b/drivers/staging/fsl-mc/include/mc-sys.h @@ -39,6 +39,13 @@ #include #include #include +#include +#include + +/** + * Bit masks for a MC I/O object (struct fsl_mc_io) flags + */ +#define FSL_MC_IO_ATOMIC_CONTEXT_PORTAL 0x0001 struct fsl_mc_resource; struct mc_command; @@ -53,14 +60,26 @@ struct mc_command; * @resource: generic resource associated with the MC portal if * the MC portal came from a resource pool, or NULL if the MC portal * is permanently bound to a device (e.g., a DPRC) + * @mutex: Mutex to serialize mc_send_command() calls that use the same MC + * portal, if the fsl_mc_io object was created with the + * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag off. mc_send_command() calls for this + * fsl_mc_io object must be made only from non-atomic context. + * @spinlock: Spinlock to serialize mc_send_command() calls that use the same MC + * portal, if the fsl_mc_io object was created with the + * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag on. mc_send_command() calls for this + * fsl_mc_io object can be made from atomic or non-atomic context. */ struct fsl_mc_io { struct device *dev; - uint32_t flags; - uint32_t portal_size; + uint16_t flags; + uint16_t portal_size; phys_addr_t portal_phys_addr; void __iomem *portal_virt_addr; struct fsl_mc_resource *resource; + union { + struct mutex mutex; /* serializes mc_send_command() calls */ + spinlock_t spinlock; /* serializes mc_send_command() calls */ + }; }; int __must_check fsl_create_mc_io(struct device *dev, -- 2.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/