Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031215AbbEEU2H (ORCPT ); Tue, 5 May 2015 16:28:07 -0400 Received: from gabe.freedesktop.org ([131.252.210.177]:49368 "EHLO gabe.freedesktop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753476AbbEEU1r (ORCPT ); Tue, 5 May 2015 16:27:47 -0400 From: Eric Anholt To: linux-arm-kernel@lists.infradead.org Cc: linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Stephen Warren , Lee Jones , devicetree@vger.kernel.org, Jassi Brar , Craig McGeachie , Lubomir Rintel , Eric Anholt Subject: [PATCH 2/3 v8] mailbox: Enable BCM2835 mailbox support Date: Tue, 5 May 2015 13:27:45 -0700 Message-Id: <1430857666-18877-2-git-send-email-eric@anholt.net> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1430857666-18877-1-git-send-email-eric@anholt.net> References: <1430857666-18877-1-git-send-email-eric@anholt.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10610 Lines: 321 From: Lubomir Rintel This mailbox driver provides a single mailbox channel to write 32-bit values to the VPU and get a 32-bit response. The Raspberry Pi firmware uses this mailbox channel to implement firmware calls, while Roku 2 (despite being derived from the same firmware tree) doesn't. The driver was originally submitted by Lubomir, based on the out-of-tree 2708 mailbox driver. Eric Anholt fixed it up for upstreaming, with the major functional change being that it now has no notion of multiple channels (since that is a firmware-dependent concept) and instead the raspberrypi-firmware driver will do that bit-twiddling in its own messages. Signed-off-by: Lubomir Rintel Signed-off-by: Craig McGeachie Signed-off-by: Eric Anholt Cc: Jassi Brar Acked-by: Stephen Warren --- v2: Squashed Craig's work for review, carried over to new version of Mailbox framework (changes by Lubomir) v3: Fix multi-line comment style. Refer to the documentation by filename. Only declare one MODULE_AUTHOR. Alphabetize includes. Drop some excessive dev_dbg()s (changes by anholt). v4: Use the new bcm2835_peripheral_read_workaround(), drop the unnecessary wmb()s, make the messages be a pointer to u32, rather than u32-cast-as-pointer, fold in small static functions, drop extra error messages, clean up sizeof() arg for malloc, disable interrupts on unload (changes by anholt). v5: Rewrite as a single-channel driver, where the old notion of channels will now be interpreted by an rpi-specific driver. Minor style fix. Drop peripheral_read_workaround() since it's been noted that readl() covers the non-interrupt half of it, and I found that we would need to resolve read ordering in the interrupt handler anyway (changes by anholt). v6: rewrite commit message, only turn on interrupts when a client is present, drop the started flag, use BIT() macro, update Broadcom copyright (changes by anholt, from Jassi's review). Drop s-o-b of Jassi and Suman, who appear to have been accidentally added by Craig (noted by Lubomir). v7: Drop the txdone-style check in send_data, since the core will make sure we're not called until the previous one is done. Fix "mbox" to be static (changes by anholt, from review by Jassi). v8: Fix compiler warning from txdone check removal. Add a summary of anholt's changes to the commit message. Supply our own of_xlate to insist that 0 mbox-cells are provided. Replace global *mbox with container_of()s. Drop our driver's extra "struct device *dev". drivers/mailbox/Kconfig | 8 ++ drivers/mailbox/Makefile | 2 + drivers/mailbox/bcm2835-mailbox.c | 217 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 227 insertions(+) create mode 100644 drivers/mailbox/bcm2835-mailbox.c diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index 84b0a2d..ab574da 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -60,4 +60,12 @@ config ALTERA_MBOX An implementation of the Altera Mailbox soft core. It is used to send message between processors. Say Y here if you want to use the Altera mailbox support. + +config BCM2835_MBOX + tristate "BCM2835 Mailbox" + depends on ARCH_BCM2835 + help + An implementation of the BCM2385 Mailbox. It is used to invoke + the services of the Videocore. Say Y here if you want to use the + BCM2835 Mailbox. endif diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index b18201e..8e6d822 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -11,3 +11,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o obj-$(CONFIG_PCC) += pcc.o obj-$(CONFIG_ALTERA_MBOX) += mailbox-altera.o + +obj-$(CONFIG_BCM2835_MBOX) += bcm2835-mailbox.o diff --git a/drivers/mailbox/bcm2835-mailbox.c b/drivers/mailbox/bcm2835-mailbox.c new file mode 100644 index 0000000..16c3453 --- /dev/null +++ b/drivers/mailbox/bcm2835-mailbox.c @@ -0,0 +1,217 @@ +/* + * Copyright (C) 2010,2015 Broadcom + * Copyright (C) 2013-2014 Lubomir Rintel + * Copyright (C) 2013 Craig McGeachie + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This device provides a mechanism for writing to the mailboxes, + * that are shared between the ARM and the VideoCore processor + * + * Parts of the driver are based on: + * - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was + * obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/ + * linux.git + * - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at + * https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/ + * mailbox/bcm2835-ipc.c + * - documentation available on the following web site: + * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Mailboxes */ +#define ARM_0_MAIL0 0x00 +#define ARM_0_MAIL1 0x20 + +/* + * Mailbox registers. We basically only support mailbox 0 & 1. We + * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See + * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about + * the placement of memory barriers. + */ +#define MAIL0_RD (ARM_0_MAIL0 + 0x00) +#define MAIL0_POL (ARM_0_MAIL0 + 0x10) +#define MAIL0_STA (ARM_0_MAIL0 + 0x18) +#define MAIL0_CNF (ARM_0_MAIL0 + 0x1C) +#define MAIL1_WRT (ARM_0_MAIL1 + 0x00) + +/* Status register: FIFO state. */ +#define ARM_MS_FULL BIT(31) +#define ARM_MS_EMPTY BIT(30) + +/* Configuration register: Enable interrupts. */ +#define ARM_MC_IHAVEDATAIRQEN BIT(0) + +struct bcm2835_mbox { + void __iomem *regs; + spinlock_t lock; + struct mbox_controller controller; +}; + +static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link) +{ + return container_of(link->mbox, struct bcm2835_mbox, controller); +} + +static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id) +{ + struct bcm2835_mbox *mbox = dev_id; + struct device *dev = mbox->controller.dev; + struct mbox_chan *link = &mbox->controller.chans[0]; + + while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) { + u32 msg = readl(mbox->regs + MAIL0_RD); + dev_dbg(dev, "Reply 0x%08X\n", msg); + mbox_chan_received_data(link, &msg); + } + return IRQ_HANDLED; +} + +static int bcm2835_send_data(struct mbox_chan *link, void *data) +{ + struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); + int ret = 0; + u32 msg = *(u32 *)data; + + spin_lock(&mbox->lock); + writel(msg, mbox->regs + MAIL1_WRT); + dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg); + spin_unlock(&mbox->lock); + return ret; +} + +static int bcm2835_startup(struct mbox_chan *link) +{ + struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); + + /* Enable the interrupt on data reception */ + writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF); + + return 0; +} + +static void bcm2835_shutdown(struct mbox_chan *link) +{ + struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); + + writel(0, mbox->regs + MAIL0_CNF); +} + +static bool bcm2835_last_tx_done(struct mbox_chan *link) +{ + struct bcm2835_mbox *mbox = bcm2835_link_mbox(link); + bool ret; + + spin_lock(&mbox->lock); + ret = !(readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL); + spin_unlock(&mbox->lock); + return ret; +} + +static struct mbox_chan_ops bcm2835_mbox_chan_ops = { + .send_data = bcm2835_send_data, + .startup = bcm2835_startup, + .shutdown = bcm2835_shutdown, + .last_tx_done = bcm2835_last_tx_done +}; + +static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox, + const struct of_phandle_args *sp) +{ + if (sp->args_count != 0) + return NULL; + + return &mbox->chans[0]; +} + +static int bcm2835_mbox_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + int ret = 0; + struct resource *iomem; + struct bcm2835_mbox *mbox; + + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); + if (mbox == NULL) + return -ENOMEM; + spin_lock_init(&mbox->lock); + + ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0), + bcm2835_mbox_irq, 0, dev_name(dev), mbox); + if (ret) { + dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n", + ret); + return -ENODEV; + } + + iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + mbox->regs = devm_ioremap_resource(&pdev->dev, iomem); + if (IS_ERR(mbox->regs)) { + ret = PTR_ERR(mbox->regs); + dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret); + return ret; + } + + mbox->controller.txdone_poll = true; + mbox->controller.txpoll_period = 5; + mbox->controller.ops = &bcm2835_mbox_chan_ops; + mbox->controller.of_xlate = &bcm2835_mbox_index_xlate; + mbox->controller.dev = dev; + mbox->controller.num_chans = 1; + mbox->controller.chans = devm_kzalloc(dev, + sizeof(*mbox->controller.chans), GFP_KERNEL); + if (!mbox->controller.chans) + return -ENOMEM; + + ret = mbox_controller_register(&mbox->controller); + if (ret) + return ret; + + platform_set_drvdata(pdev, mbox); + dev_info(dev, "mailbox enabled\n"); + + return ret; +} + +static int bcm2835_mbox_remove(struct platform_device *pdev) +{ + struct bcm2835_mbox *mbox = platform_get_drvdata(pdev); + mbox_controller_unregister(&mbox->controller); + return 0; +} + +static const struct of_device_id bcm2835_mbox_of_match[] = { + { .compatible = "brcm,bcm2835-mbox", }, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match); + +static struct platform_driver bcm2835_mbox_driver = { + .driver = { + .name = "bcm2835-mbox", + .owner = THIS_MODULE, + .of_match_table = bcm2835_mbox_of_match, + }, + .probe = bcm2835_mbox_probe, + .remove = bcm2835_mbox_remove, +}; +module_platform_driver(bcm2835_mbox_driver); + +MODULE_AUTHOR("Lubomir Rintel "); +MODULE_DESCRIPTION("BCM2835 mailbox IPC driver"); +MODULE_LICENSE("GPL v2"); -- 2.1.4 -- 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/