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bcm27xx: patches: cherry-pick for RP1 kmods
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Cherry-pick patches to support building RP1 modules.

Signed-off-by: John Audia <therealgraysky@proton.me>
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graysky2 committed Dec 12, 2024
1 parent a2f0cd3 commit ee05db1
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252 changes: 252 additions & 0 deletions target/linux/bcm27xx/patches-6.6/950-1351-mailbox-Add-RP1-mailbox-support.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,252 @@
From 0d58d8cfb6f989f290d983552fcaa116e582e84a Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 31 Oct 2024 17:33:38 +0000
Subject: [PATCH] mailbox: Add RP1 mailbox support

The Raspberry Pi RP1 includes 2 M3 cores running firmware. This driver
adds a mailbox communication channel to them via a doorbell and some
shared memory.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/mailbox/Kconfig | 9 ++
drivers/mailbox/Makefile | 2 +
drivers/mailbox/rp1-mailbox.c | 208 ++++++++++++++++++++++++++++++++++
3 files changed, 219 insertions(+)
create mode 100644 drivers/mailbox/rp1-mailbox.c

--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -295,4 +295,13 @@ config QCOM_IPCC
acts as an interrupt controller for receiving interrupts from clients.
Say Y here if you want to build this driver.

+config MBOX_RP1
+ tristate "RP1 Mailbox"
+ depends on MFD_RP1
+ help
+ An implementation of a mailbox interface to the Raspberry Pi RP1 I/O
+ interface. Although written as a mailbox driver, the hardware only
+ provides an array of 32 doorbells.
+ Say Y here if you want to use the RP1 Mailbox.
+
endif
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -62,3 +62,5 @@ obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox
obj-$(CONFIG_QCOM_IPCC) += qcom-ipcc.o

obj-$(CONFIG_APPLE_MAILBOX) += apple-mailbox.o
+
+obj-$(CONFIG_MBOX_RP1) += rp1-mailbox.o
--- /dev/null
+++ b/drivers/mailbox/rp1-mailbox.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Raspberry Pi Ltd.
+ *
+ * Parts of this driver are based on:
+ * - bcm2835-mailbox.c
+ * Copyright (C) 2010,2015 Broadcom
+ * Copyright (C) 2013-2014 Lubomir Rintel
+ * Copyright (C) 2013 Craig McGeachie
+ */
+
+#include <linux/compat.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+/*
+ * RP1's PROC_EVENTS register can generate interrupts on the M3 cores (when
+ * enabled). The 32-bit register is treated as 32 events, all of which share a
+ * common interrupt. HOST_EVENTS is the same in the reverse direction.
+ */
+#define SYSCFG_PROC_EVENTS 0x00000008
+#define SYSCFG_HOST_EVENTS 0x0000000c
+#define SYSCFG_HOST_EVENT_IRQ_EN 0x00000010
+#define SYSCFG_HOST_EVENT_IRQ 0x00000014
+
+#define HW_SET_BITS 0x00002000
+#define HW_CLR_BITS 0x00003000
+
+#define MAX_CHANS 4 /* 32 is the hardware limit */
+
+struct rp1_mbox {
+ void __iomem *regs;
+ unsigned int irq;
+ struct mbox_controller controller;
+};
+
+static struct rp1_mbox *rp1_chan_mbox(struct mbox_chan *chan)
+{
+ return container_of(chan->mbox, struct rp1_mbox, controller);
+}
+
+static unsigned int rp1_chan_event(struct mbox_chan *chan)
+{
+ return (unsigned int)(uintptr_t)chan->con_priv;
+}
+
+static irqreturn_t rp1_mbox_irq(int irq, void *dev_id)
+{
+ struct rp1_mbox *mbox = dev_id;
+ struct mbox_chan *chan;
+ unsigned int doorbell;
+ unsigned int evs;
+
+ evs = readl(mbox->regs + SYSCFG_HOST_EVENT_IRQ);
+ writel(evs, mbox->regs + SYSCFG_HOST_EVENTS + HW_CLR_BITS);
+
+ while (evs) {
+ doorbell = __ffs(evs);
+ chan = &mbox->controller.chans[doorbell];
+ mbox_chan_received_data(chan, NULL);
+ evs &= ~(1 << doorbell);
+ }
+ return IRQ_HANDLED;
+}
+
+static int rp1_send_data(struct mbox_chan *chan, void *data)
+{
+ struct rp1_mbox *mbox = rp1_chan_mbox(chan);
+ unsigned int event = rp1_chan_event(chan);
+
+ writel(event, mbox->regs + SYSCFG_PROC_EVENTS + HW_SET_BITS);
+
+ return 0;
+}
+
+static int rp1_startup(struct mbox_chan *chan)
+{
+ struct rp1_mbox *mbox = rp1_chan_mbox(chan);
+ unsigned int event = rp1_chan_event(chan);
+
+ writel(event, mbox->regs + SYSCFG_HOST_EVENT_IRQ_EN + HW_SET_BITS);
+
+ return 0;
+}
+
+static void rp1_shutdown(struct mbox_chan *chan)
+{
+ struct rp1_mbox *mbox = rp1_chan_mbox(chan);
+ unsigned int event = rp1_chan_event(chan);
+
+ writel(event, mbox->regs + SYSCFG_HOST_EVENT_IRQ_EN + HW_CLR_BITS);
+}
+
+static bool rp1_last_tx_done(struct mbox_chan *chan)
+{
+ struct rp1_mbox *mbox = rp1_chan_mbox(chan);
+ unsigned int event = rp1_chan_event(chan);
+ unsigned int evs;
+
+ evs = readl(mbox->regs + SYSCFG_HOST_EVENT_IRQ);
+
+ return !(evs & event);
+}
+
+static const struct mbox_chan_ops rp1_mbox_chan_ops = {
+ .send_data = rp1_send_data,
+ .startup = rp1_startup,
+ .shutdown = rp1_shutdown,
+ .last_tx_done = rp1_last_tx_done
+};
+
+static struct mbox_chan *rp1_mbox_xlate(struct mbox_controller *mbox,
+ const struct of_phandle_args *spec)
+{
+ struct mbox_chan *chan;
+ unsigned int doorbell;
+
+ if (spec->args_count != 1)
+ return ERR_PTR(-EINVAL);
+
+ doorbell = spec->args[0];
+ if (doorbell >= MAX_CHANS)
+ return ERR_PTR(-EINVAL);
+
+ chan = &mbox->chans[doorbell];
+ if (chan->con_priv)
+ return ERR_PTR(-EBUSY);
+
+ chan->con_priv = (void *)(uintptr_t)(1 << doorbell);
+
+ return chan;
+}
+
+static int rp1_mbox_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mbox_chan *chans;
+ struct rp1_mbox *mbox;
+ int ret = 0;
+
+ mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+ if (mbox == NULL)
+ return -ENOMEM;
+
+ ret = devm_request_irq(dev, platform_get_irq(pdev, 0),
+ rp1_mbox_irq, 0, dev_name(dev), mbox);
+ if (ret) {
+ dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
+ ret);
+ return -ENODEV;
+ }
+
+ mbox->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(mbox->regs)) {
+ ret = PTR_ERR(mbox->regs);
+ return ret;
+ }
+
+ chans = devm_kcalloc(dev, MAX_CHANS, sizeof(*chans), GFP_KERNEL);
+ if (!chans)
+ return -ENOMEM;
+
+ mbox->controller.txdone_poll = true;
+ mbox->controller.txpoll_period = 5;
+ mbox->controller.ops = &rp1_mbox_chan_ops;
+ mbox->controller.of_xlate = &rp1_mbox_xlate;
+ mbox->controller.dev = dev;
+ mbox->controller.num_chans = MAX_CHANS;
+ mbox->controller.chans = chans;
+
+ ret = devm_mbox_controller_register(dev, &mbox->controller);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, mbox);
+
+ return 0;
+}
+
+static const struct of_device_id rp1_mbox_of_match[] = {
+ { .compatible = "raspberrypi,rp1-mbox", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rp1_mbox_of_match);
+
+static struct platform_driver rp1_mbox_driver = {
+ .driver = {
+ .name = "rp1-mbox",
+ .of_match_table = rp1_mbox_of_match,
+ },
+ .probe = rp1_mbox_probe,
+};
+
+module_platform_driver(rp1_mbox_driver);
+
+MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
+MODULE_DESCRIPTION("RP1 mailbox IPC driver");
+MODULE_LICENSE("GPL v2");
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