[PATCH V6 05/12] mailbox: Add NVIDIA Tegra XUSB mailbox driver

Andrew Bresticker
2014-11-25T00:20:37Z

The Tegra xHCI controller's firmware communicates requests to the host
processor through a mailbox interface. While there is only a single
physical channel, messages sent by the controller can be divided
into two groups: those intended for the PHY driver and those intended
for the host-controller driver. The requesting driver is assigned
one of two virtual channels when the single physical channel is
requested. All incoming messages are sent to both virtual channels.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
---
Thierry,

I've left this as a separate driver because I don't think it should be
combined with the xHCI host. Stephen and I discussed this earlier in
review of v1 of this series and he agreed that the mailbox belongs in
its own DT node and driver.

Changes from v5:
- Poll for TX completion using MBOX_OWNER field.
Changes from v4:
- Use chan->cl to indicate channel allocation status
- Addressed review comments from Thierry
No changes from v3.
Changes from v2:
- Fixed mailbox IRQ vs. channel alloc/free race.
- Renamed defines to match TRM.
- Dropped channel specifier and instead allocated virtual channels as they
were requested.
- Removed MODULE_ALIAS.
Changes from v1:
- Converted to common mailbox framework.
- Removed useless polling sequences in TX path.
- Moved xusb include from linux/ to soc/tegra/
---
drivers/mailbox/Kconfig | 3 +
drivers/mailbox/Makefile | 2 +
drivers/mailbox/tegra-xusb-mailbox.c | 278 +++++++++++++++++++++++++++++++++++
include/soc/tegra/xusb.h | 43 ++++++
4 files changed, 326 insertions(+)
create mode 100644 drivers/mailbox/tegra-xusb-mailbox.c
create mode 100644 include/soc/tegra/xusb.h

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 9fd9c67..97369c2 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -33,4 +33,7 @@ config OMAP_MBOX_KFIFO_SIZE
Specify the default size of mailbox's kfifo buffers (bytes).
This can also be changed at runtime (via the mbox_kfifo_size
module parameter).
+
+config TEGRA_XUSB_MBOX
+ def_bool y if ARCH_TEGRA
endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 94ed7ce..7f0af9c 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -5,3 +5,5 @@ obj-$(CONFIG_MAILBOX) += mailbox.o
obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o

obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o
+
+obj-$(CONFIG_TEGRA_XUSB_MBOX) += tegra-xusb-mailbox.o
diff --git a/drivers/mailbox/tegra-xusb-mailbox.c b/drivers/mailbox/tegra-xusb-mailbox.c
new file mode 100644
index 0000000..d5874e4
--- /dev/null
+++ b/drivers/mailbox/tegra-xusb-mailbox.c
@@ -0,0 +1,278 @@
+/*
+ * NVIDIA Tegra XUSB mailbox driver
+ *
+ * Copyright (C) 2014 NVIDIA Corporation
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <soc/tegra/xusb.h>
+
+#define XUSB_MBOX_NUM_CHANS 2 /* Host + PHY */
+
+#define XUSB_CFG_ARU_MBOX_CMD 0xe4
+#define MBOX_DEST_FALC BIT(27)
+#define MBOX_DEST_PME BIT(28)
+#define MBOX_DEST_SMI BIT(29)
+#define MBOX_DEST_XHCI BIT(30)
+#define MBOX_INT_EN BIT(31)
+#define XUSB_CFG_ARU_MBOX_DATA_IN 0xe8
+#define CMD_DATA_SHIFT 0
+#define CMD_DATA_MASK 0xffffff
+#define CMD_TYPE_SHIFT 24
+#define CMD_TYPE_MASK 0xff
+#define XUSB_CFG_ARU_MBOX_DATA_OUT 0xec
+#define XUSB_CFG_ARU_MBOX_OWNER 0xf0
+#define MBOX_OWNER_NONE 0
+#define MBOX_OWNER_FW 1
+#define MBOX_OWNER_SW 2
+#define XUSB_CFG_ARU_SMI_INTR 0x428
+#define MBOX_SMI_INTR_FW_HANG BIT(1)
+#define MBOX_SMI_INTR_EN BIT(3)
+
+struct tegra_xusb_mbox {
+ struct mbox_controller mbox;
+ void __iomem *regs;
+ spinlock_t lock;
+};
+
+static inline u32 mbox_readl(struct tegra_xusb_mbox *mbox, unsigned long offset)
+{
+ return readl(mbox->regs + offset);
+}
+
+static inline void mbox_writel(struct tegra_xusb_mbox *mbox, u32 val,
+ unsigned long offset)
+{
+ writel(val, mbox->regs + offset);
+}
+
+static inline struct tegra_xusb_mbox *to_tegra_mbox(struct mbox_controller *c)
+{
+ return container_of(c, struct tegra_xusb_mbox, mbox);
+}
+
+static inline u32 mbox_pack_msg(struct tegra_xusb_mbox_msg *msg)
+{
+ u32 val;
+
+ val = (msg->cmd & CMD_TYPE_MASK) << CMD_TYPE_SHIFT;
+ val |= (msg->data & CMD_DATA_MASK) << CMD_DATA_SHIFT;
+
+ return val;
+}
+
+static inline void mbox_unpack_msg(u32 val, struct tegra_xusb_mbox_msg *msg)
+{
+ msg->cmd = (val >> CMD_TYPE_SHIFT) & CMD_TYPE_MASK;
+ msg->data = (val >> CMD_DATA_SHIFT) & CMD_DATA_MASK;
+}
+
+static int tegra_xusb_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+ struct tegra_xusb_mbox *mbox = to_tegra_mbox(chan->mbox);
+ struct tegra_xusb_mbox_msg *msg = data;
+ unsigned long flags;
+ u32 reg, owner;
+
+ dev_dbg(mbox->mbox.dev, "TX message %#x:%#x\n", msg->cmd, msg->data);
+
+ /* ACK/NAK must be sent with the controller as the mailbox owner */
+ if (msg->cmd == MBOX_CMD_ACK || msg->cmd == MBOX_CMD_NAK)
+ owner = MBOX_OWNER_FW;
+ else
+ owner = MBOX_OWNER_SW;
+
+ spin_lock_irqsave(&mbox->lock, flags);
+
+ /* Acquire mailbox */
+ if (mbox_readl(mbox, XUSB_CFG_ARU_MBOX_OWNER) != MBOX_OWNER_NONE) {
+ dev_err(mbox->mbox.dev, "Mailbox not idle\n");
+ goto busy;
+ }
+ mbox_writel(mbox, owner, XUSB_CFG_ARU_MBOX_OWNER);
+ if (mbox_readl(mbox, XUSB_CFG_ARU_MBOX_OWNER) != owner) {
+ dev_err(mbox->mbox.dev, "Failed to acquire mailbox");
+ goto busy;
+ }
+
+ mbox_writel(mbox, mbox_pack_msg(msg), XUSB_CFG_ARU_MBOX_DATA_IN);
+ reg = mbox_readl(mbox, XUSB_CFG_ARU_MBOX_CMD);
+ reg |= MBOX_INT_EN | MBOX_DEST_FALC;
+ mbox_writel(mbox, reg, XUSB_CFG_ARU_MBOX_CMD);
+
+ spin_unlock_irqrestore(&mbox->lock, flags);
+
+ return 0;
+busy:
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return -EBUSY;
+}
+
+static int tegra_xusb_mbox_startup(struct mbox_chan *chan)
+{
+ return 0;
+}
+
+static void tegra_xusb_mbox_shutdown(struct mbox_chan *chan)
+{
+}
+
+static bool tegra_xusb_mbox_last_tx_done(struct mbox_chan *chan)
+{
+ struct tegra_xusb_mbox *mbox = to_tegra_mbox(chan->mbox);
+
+ return mbox_readl(mbox, XUSB_CFG_ARU_MBOX_OWNER) == MBOX_OWNER_NONE;
+}
+
+static const struct mbox_chan_ops tegra_xusb_mbox_chan_ops = {
+ .send_data = tegra_xusb_mbox_send_data,
+ .startup = tegra_xusb_mbox_startup,
+ .shutdown = tegra_xusb_mbox_shutdown,
+ .last_tx_done = tegra_xusb_mbox_last_tx_done,
+};
+
+static irqreturn_t tegra_xusb_mbox_irq(int irq, void *p)
+{
+ struct tegra_xusb_mbox *mbox = p;
+ struct tegra_xusb_mbox_msg msg;
+ unsigned int i;
+ u32 reg;
+
+ spin_lock(&mbox->lock);
+
+ /* Clear mbox interrupts */
+ reg = mbox_readl(mbox, XUSB_CFG_ARU_SMI_INTR);
+ if (reg & MBOX_SMI_INTR_FW_HANG)
+ dev_err(mbox->mbox.dev, "Controller firmware hang\n");
+ mbox_writel(mbox, reg, XUSB_CFG_ARU_SMI_INTR);
+
+ reg = mbox_readl(mbox, XUSB_CFG_ARU_MBOX_DATA_OUT);
+ mbox_unpack_msg(reg, &msg);
+
+ /*
+ * Set the mailbox back to idle. The recipient of the message is
+ * responsible for sending an ACK/NAK, if necessary.
+ */
+ reg = mbox_readl(mbox, XUSB_CFG_ARU_MBOX_CMD);
+ reg &= ~MBOX_DEST_SMI;
+ mbox_writel(mbox, reg, XUSB_CFG_ARU_MBOX_CMD);
+ mbox_writel(mbox, MBOX_OWNER_NONE, XUSB_CFG_ARU_MBOX_OWNER);
+
+ dev_dbg(mbox->mbox.dev, "RX message %#x:%#x\n", msg.cmd, msg.data);
+ for (i = 0; i < XUSB_MBOX_NUM_CHANS; i++) {
+ if (mbox->mbox.chans[i].cl)
+ mbox_chan_received_data(&mbox->mbox.chans[i], &msg);
+ }
+
+ spin_unlock(&mbox->lock);
+
+ return IRQ_HANDLED;
+}
+
+static struct mbox_chan *tegra_xusb_mbox_of_xlate(struct mbox_controller *ctlr,
+ const struct of_phandle_args *sp)
+{
+ struct tegra_xusb_mbox *mbox = to_tegra_mbox(ctlr);
+ struct mbox_chan *chan = ERR_PTR(-EINVAL);
+ unsigned long flags;
+ unsigned int i;
+
+ /* Pick the first available (virtual) channel. */
+ spin_lock_irqsave(&mbox->lock, flags);
+ for (i = 0; XUSB_MBOX_NUM_CHANS; i++) {
+ if (!ctlr->chans[i].cl) {
+ chan = &ctlr->chans[i];
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&mbox->lock, flags);
+
+ return chan;
+}
+
+static const struct of_device_id tegra_xusb_mbox_of_match[] = {
+ { .compatible = "nvidia,tegra124-xusb-mbox" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, tegra_xusb_mbox_of_match);
+
+static int tegra_xusb_mbox_probe(struct platform_device *pdev)
+{
+ struct tegra_xusb_mbox *mbox;
+ struct resource *res;
+ int irq, ret;
+
+ mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, mbox);
+ spin_lock_init(&mbox->lock);
+
+ mbox->mbox.dev = &pdev->dev;
+ mbox->mbox.chans = devm_kcalloc(&pdev->dev, XUSB_MBOX_NUM_CHANS,
+ sizeof(*mbox->mbox.chans), GFP_KERNEL);
+ if (!mbox->mbox.chans)
+ return -ENOMEM;
+ mbox->mbox.num_chans = XUSB_MBOX_NUM_CHANS;
+ mbox->mbox.ops = &tegra_xusb_mbox_chan_ops;
+ mbox->mbox.txdone_poll = true;
+ mbox->mbox.txpoll_period = 1;
+ mbox->mbox.of_xlate = tegra_xusb_mbox_of_xlate;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+ mbox->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+ if (!mbox->regs)
+ return -ENOMEM;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+ ret = devm_request_irq(&pdev->dev, irq, tegra_xusb_mbox_irq, 0,
+ dev_name(&pdev->dev), mbox);
+ if (ret < 0)
+ return ret;
+
+ ret = mbox_controller_register(&mbox->mbox);
+ if (ret < 0)
+ dev_err(&pdev->dev, "failed to register mailbox: %d\n", ret);
+
+ return ret;
+}
+
+static int tegra_xusb_mbox_remove(struct platform_device *pdev)
+{
+ struct tegra_xusb_mbox *mbox = platform_get_drvdata(pdev);
+
+ mbox_controller_unregister(&mbox->mbox);
+
+ return 0;
+}
+
+static struct platform_driver tegra_xusb_mbox_driver = {
+ .probe = tegra_xusb_mbox_probe,
+ .remove = tegra_xusb_mbox_remove,
+ .driver = {
+ .name = "tegra-xusb-mbox",
+ .of_match_table = of_match_ptr(tegra_xusb_mbox_of_match),
+ },
+};
+module_platform_driver(tegra_xusb_mbox_driver);
+
+MODULE_AUTHOR("Andrew Bresticker <abrestic@chromium.org>");
+MODULE_DESCRIPTION("NVIDIA Tegra XUSB mailbox driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/soc/tegra/xusb.h b/include/soc/tegra/xusb.h
new file mode 100644
index 0000000..5ce5e12
--- /dev/null
+++ b/include/soc/tegra/xusb.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2014 NVIDIA Corporation
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#ifndef __SOC_TEGRA_XUSB_H__
+#define __SOC_TEGRA_XUSB_H__
+
+/* Command requests from the firmware */
+enum tegra_xusb_mbox_cmd {
+ MBOX_CMD_MSG_ENABLED = 1,
+ MBOX_CMD_INC_FALC_CLOCK,
+ MBOX_CMD_DEC_FALC_CLOCK,
+ MBOX_CMD_INC_SSPI_CLOCK,
+ MBOX_CMD_DEC_SSPI_CLOCK,
+ MBOX_CMD_SET_BW, /* no ACK/NAK required */
+ MBOX_CMD_SET_SS_PWR_GATING,
+ MBOX_CMD_SET_SS_PWR_UNGATING,
+ MBOX_CMD_SAVE_DFE_CTLE_CTX,
+ MBOX_CMD_AIRPLANE_MODE_ENABLED, /* unused */
+ MBOX_CMD_AIRPLANE_MODE_DISABLED, /* unused */
+ MBOX_CMD_START_HSIC_IDLE,
+ MBOX_CMD_STOP_HSIC_IDLE,
+ MBOX_CMD_DBC_WAKE_STACK, /* unused */
+ MBOX_CMD_HSIC_PRETEND_CONNECT,
+
+ MBOX_CMD_MAX,
+
+ /* Response message to above commands */
+ MBOX_CMD_ACK = 128,
+ MBOX_CMD_NAK
+};
+
+struct tegra_xusb_mbox_msg {
+ u32 cmd;
+ u32 data;
+};
+
+#endif /* __SOC_TEGRA_XUSB_H__ */
--
2.1.0.rc2.206.gedb03e5