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SubjectRe: [PATCH v3 2/2] mailbox: sprd: Add Spreadtrum mailbox driver
Hi Jassi,

On Wed, Apr 1, 2020 at 1:57 PM Baolin Wang <baolin.wang7@gmail.com> wrote:
>
> From: Baolin Wang <baolin.wang@unisoc.com>
>
> The Spreadtrum mailbox controller supports 8 channels to communicate
> with MCUs, and it contains 2 different parts: inbox and outbox, which
> are used to send and receive messages by IRQ mode.
>
> Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
> Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>

Do you have any comments for this patch? Thanks.

> ---
> Changes from v2:
> - None.
>
> Changes from v1:
> - None
> ---
> drivers/mailbox/Kconfig | 8 +
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/sprd-mailbox.c | 350 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 360 insertions(+)
> create mode 100644 drivers/mailbox/sprd-mailbox.c
>
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index ab4eb75..a33eaab 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -227,4 +227,12 @@ config ZYNQMP_IPI_MBOX
> message to the IPI buffer and will access the IPI control
> registers to kick the other processor or enquire status.
>
> +config SPRD_MBOX
> + tristate "Spreadtrum Mailbox"
> + depends on ARCH_SPRD || COMPILE_TEST
> + help
> + Mailbox driver implementation for the Spreadtrum platform. It is used
> + to send message between application processors and MCU. Say Y here if
> + you want to build the Spreatrum mailbox controller driver.
> +
> endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index c22fad6..0f47b6b 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -48,3 +48,5 @@ obj-$(CONFIG_STM32_IPCC) += stm32-ipcc.o
> obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o
>
> obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o
> +
> +obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox.o
> diff --git a/drivers/mailbox/sprd-mailbox.c b/drivers/mailbox/sprd-mailbox.c
> new file mode 100644
> index 0000000..58e5388
> --- /dev/null
> +++ b/drivers/mailbox/sprd-mailbox.c
> @@ -0,0 +1,350 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Spreadtrum mailbox driver
> + *
> + * Copyright (c) 2020 Spreadtrum Communications Inc.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +
> +#define SPRD_MBOX_ID 0x0
> +#define SPRD_MBOX_MSG_LOW 0x4
> +#define SPRD_MBOX_MSG_HIGH 0x8
> +#define SPRD_MBOX_TRIGGER 0xc
> +#define SPRD_MBOX_FIFO_RST 0x10
> +#define SPRD_MBOX_FIFO_STS 0x14
> +#define SPRD_MBOX_IRQ_STS 0x18
> +#define SPRD_MBOX_IRQ_MSK 0x1c
> +#define SPRD_MBOX_LOCK 0x20
> +#define SPRD_MBOX_FIFO_DEPTH 0x24
> +
> +/* Bit and mask definiation for inbox's SPRD_MBOX_FIFO_STS register */
> +#define SPRD_INBOX_FIFO_DELIVER_MASK GENMASK(23, 16)
> +#define SPRD_INBOX_FIFO_OVERLOW_MASK GENMASK(15, 8)
> +#define SPRD_INBOX_FIFO_DELIVER_SHIFT 16
> +#define SPRD_INBOX_FIFO_BUSY_MASK GENMASK(7, 0)
> +
> +/* Bit and mask definiation for SPRD_MBOX_IRQ_STS register */
> +#define SPRD_MBOX_IRQ_CLR BIT(0)
> +
> +/* Bit and mask definiation for outbox's SPRD_MBOX_FIFO_STS register */
> +#define SPRD_OUTBOX_FIFO_FULL BIT(0)
> +#define SPRD_OUTBOX_FIFO_WR_SHIFT 16
> +#define SPRD_OUTBOX_FIFO_RD_SHIFT 24
> +#define SPRD_OUTBOX_FIFO_POS_MASK GENMASK(7, 0)
> +
> +/* Bit and mask definiation for inbox's SPRD_MBOX_IRQ_MSK register */
> +#define SPRD_INBOX_FIFO_BLOCK_IRQ BIT(0)
> +#define SPRD_INBOX_FIFO_OVERFLOW_IRQ BIT(1)
> +#define SPRD_INBOX_FIFO_DELIVER_IRQ BIT(2)
> +#define SPRD_INBOX_FIFO_IRQ_MASK GENMASK(2, 0)
> +
> +/* Bit and mask definiation for outbox's SPRD_MBOX_IRQ_MSK register */
> +#define SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ BIT(0)
> +#define SPRD_OUTBOX_FIFO_IRQ_MASK GENMASK(4, 0)
> +
> +#define SPRD_MBOX_CHAN_MAX 8
> +
> +struct sprd_mbox_chan {
> + u8 id;
> + struct mbox_chan *chan;
> +};
> +
> +struct sprd_mbox_priv {
> + struct mbox_controller mbox;
> + struct device *dev;
> + void __iomem *inbox_base;
> + void __iomem *outbox_base;
> + struct clk *clk;
> + u32 outbox_fifo_depth;
> +
> + struct sprd_mbox_chan mchan[SPRD_MBOX_CHAN_MAX];
> + struct mbox_chan chan[SPRD_MBOX_CHAN_MAX];
> +};
> +
> +static struct sprd_mbox_priv *to_sprd_mbox_priv(struct mbox_controller *mbox)
> +{
> + return container_of(mbox, struct sprd_mbox_priv, mbox);
> +}
> +
> +static u32 sprd_mbox_get_fifo_len(struct sprd_mbox_priv *priv, u32 fifo_sts)
> +{
> + u32 wr_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_WR_SHIFT) &
> + SPRD_OUTBOX_FIFO_POS_MASK;
> + u32 rd_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_RD_SHIFT) &
> + SPRD_OUTBOX_FIFO_POS_MASK;
> + u32 fifo_len;
> +
> + /*
> + * If the read pointer is equal with write pointer, which means the fifo
> + * is full or empty.
> + */
> + if (wr_pos == rd_pos) {
> + if (fifo_sts & SPRD_OUTBOX_FIFO_FULL)
> + fifo_len = priv->outbox_fifo_depth;
> + else
> + fifo_len = 0;
> + } else if (wr_pos > rd_pos) {
> + fifo_len = wr_pos - rd_pos;
> + } else {
> + fifo_len = priv->outbox_fifo_depth - rd_pos + wr_pos;
> + }
> +
> + return fifo_len;
> +}
> +
> +static irqreturn_t sprd_mbox_outbox_isr(int irq, void *data)
> +{
> + struct sprd_mbox_priv *priv = data;
> + struct sprd_mbox_chan *mchan;
> + u32 fifo_sts, fifo_len, msg[2];
> + int i, id;
> +
> + fifo_sts = readl(priv->outbox_base + SPRD_MBOX_FIFO_STS);
> +
> + fifo_len = sprd_mbox_get_fifo_len(priv, fifo_sts);
> + if (!fifo_len) {
> + dev_warn_ratelimited(priv->dev, "spurious outbox interrupt\n");
> + return IRQ_NONE;
> + }
> +
> + for (i = 0; i < fifo_len; i++) {
> + msg[0] = readl(priv->outbox_base + SPRD_MBOX_MSG_LOW);
> + msg[1] = readl(priv->outbox_base + SPRD_MBOX_MSG_HIGH);
> + id = readl(priv->outbox_base + SPRD_MBOX_ID);
> +
> + mchan = &priv->mchan[id];
> + mbox_chan_received_data(mchan->chan, (void *)msg);
> +
> + /* Trigger to update outbox FIFO pointer */
> + writel(0x1, priv->outbox_base + SPRD_MBOX_TRIGGER);
> + }
> +
> + /* Clear irq status after reading all message. */
> + writel(SPRD_MBOX_IRQ_CLR, priv->outbox_base + SPRD_MBOX_IRQ_STS);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t sprd_mbox_inbox_isr(int irq, void *data)
> +{
> + struct sprd_mbox_priv *priv = data;
> + struct sprd_mbox_chan *mchan;
> + u32 fifo_sts, send_sts, id;
> +
> + fifo_sts = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS);
> +
> + /* Get the inbox data delivery status */
> + send_sts = (fifo_sts & SPRD_INBOX_FIFO_DELIVER_MASK) >>
> + SPRD_INBOX_FIFO_DELIVER_SHIFT;
> + if (!send_sts) {
> + dev_warn_ratelimited(priv->dev, "spurious inbox interrupt\n");
> + return IRQ_NONE;
> + }
> +
> + while (send_sts) {
> + id = __ffs(send_sts);
> + send_sts &= (send_sts - 1);
> +
> + mchan = &priv->mchan[id];
> + mbox_chan_txdone(mchan->chan, 0);
> + }
> +
> + /* Clear FIFO delivery and overflow status */
> + writel(fifo_sts &
> + (SPRD_INBOX_FIFO_DELIVER_MASK | SPRD_INBOX_FIFO_OVERLOW_MASK),
> + priv->inbox_base + SPRD_MBOX_FIFO_RST);
> +
> + /* Clear irq status */
> + writel(SPRD_MBOX_IRQ_CLR, priv->inbox_base + SPRD_MBOX_IRQ_STS);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int sprd_mbox_send_data(struct mbox_chan *chan, void *msg)
> +{
> + struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
> + struct sprd_mbox_chan *mchan = chan->con_priv;
> + u32 *data = msg, busy;
> +
> + /*
> + * Check if current channel is busy or not, and we can not send data
> + * if current channel is busy.
> + */
> + busy = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS) &
> + SPRD_INBOX_FIFO_BUSY_MASK;
> + if (busy & BIT(mchan->id)) {
> + dev_err(priv->dev, "Channel %d is busy\n", mchan->id);
> + return -EBUSY;
> + }
> +
> + /* Write data into inbox FIFO, and only support 8 bytes every time */
> + writel(data[0], priv->inbox_base + SPRD_MBOX_MSG_LOW);
> + writel(data[1], priv->inbox_base + SPRD_MBOX_MSG_HIGH);
> +
> + /* Set target core id */
> + writel(mchan->id, priv->inbox_base + SPRD_MBOX_ID);
> +
> + /* Trigger remote request */
> + writel(0x1, priv->inbox_base + SPRD_MBOX_TRIGGER);
> +
> + return 0;
> +}
> +
> +static int sprd_mbox_startup(struct mbox_chan *chan)
> +{
> + struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
> + u32 val;
> +
> + /* Select outbox FIFO mode and reset the outbox FIFO status */
> + writel(0x0, priv->outbox_base + SPRD_MBOX_FIFO_RST);
> +
> + /* Enable inbox FIFO overflow and delivery interrupt */
> + val = readl(priv->inbox_base + SPRD_MBOX_IRQ_MSK);
> + val &= ~(SPRD_INBOX_FIFO_OVERFLOW_IRQ | SPRD_INBOX_FIFO_DELIVER_IRQ);
> + writel(val, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
> +
> + /* Enable outbox FIFO not empty interrupt */
> + val = readl(priv->outbox_base + SPRD_MBOX_IRQ_MSK);
> + val &= ~SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ;
> + writel(val, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
> +
> + return 0;
> +}
> +
> +static void sprd_mbox_shutdown(struct mbox_chan *chan)
> +{
> + struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
> +
> + /* Disable inbox & outbox interrupt */
> + writel(SPRD_INBOX_FIFO_IRQ_MASK, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
> + writel(SPRD_OUTBOX_FIFO_IRQ_MASK, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
> +}
> +
> +static const struct mbox_chan_ops sprd_mbox_ops = {
> + .send_data = sprd_mbox_send_data,
> + .startup = sprd_mbox_startup,
> + .shutdown = sprd_mbox_shutdown,
> +};
> +
> +static void sprd_mbox_disable(void *data)
> +{
> + struct sprd_mbox_priv *priv = data;
> +
> + clk_disable_unprepare(priv->clk);
> +}
> +
> +static int sprd_mbox_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct sprd_mbox_priv *priv;
> + int i, ret, inbox_irq, outbox_irq;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->dev = dev;
> +
> + /*
> + * The Spreadtrum mailbox uses an inbox to send messages to the target
> + * core, and uses an outbox to receive messages from other cores.
> + *
> + * Thus the mailbox controller supplies 2 different register addresses
> + * and IRQ numbers for inbox and outbox.
> + */
> + priv->inbox_base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->inbox_base))
> + return PTR_ERR(priv->inbox_base);
> +
> + priv->outbox_base = devm_platform_ioremap_resource(pdev, 1);
> + if (IS_ERR(priv->outbox_base))
> + return PTR_ERR(priv->outbox_base);
> +
> + priv->clk = devm_clk_get(dev, "enable");
> + if (IS_ERR(priv->clk)) {
> + dev_err(dev, "failed to get mailbox clock\n");
> + return PTR_ERR(priv->clk);
> + }
> +
> + ret = clk_prepare_enable(priv->clk);
> + if (ret)
> + return ret;
> +
> + ret = devm_add_action_or_reset(dev, sprd_mbox_disable, priv);
> + if (ret) {
> + dev_err(dev, "failed to add mailbox disable action\n");
> + return ret;
> + }
> +
> + inbox_irq = platform_get_irq(pdev, 0);
> + if (inbox_irq < 0)
> + return inbox_irq;
> +
> + ret = devm_request_irq(dev, inbox_irq, sprd_mbox_inbox_isr,
> + IRQF_NO_SUSPEND, dev_name(dev), priv);
> + if (ret) {
> + dev_err(dev, "failed to request inbox IRQ: %d\n", ret);
> + return ret;
> + }
> +
> + outbox_irq = platform_get_irq(pdev, 1);
> + if (outbox_irq < 0)
> + return outbox_irq;
> +
> + ret = devm_request_irq(dev, outbox_irq, sprd_mbox_outbox_isr,
> + IRQF_NO_SUSPEND, dev_name(dev), priv);
> + if (ret) {
> + dev_err(dev, "failed to request outbox IRQ: %d\n", ret);
> + return ret;
> + }
> +
> + /* Get the default outbox FIFO depth */
> + priv->outbox_fifo_depth =
> + readl(priv->outbox_base + SPRD_MBOX_FIFO_DEPTH) + 1;
> + priv->mbox.dev = dev;
> + priv->mbox.chans = &priv->chan[0];
> + priv->mbox.num_chans = SPRD_MBOX_CHAN_MAX;
> + priv->mbox.ops = &sprd_mbox_ops;
> + priv->mbox.txdone_irq = true;
> +
> + for (i = 0; i < SPRD_MBOX_CHAN_MAX; i++) {
> + priv->chan[i].con_priv = &priv->mchan[i];
> +
> + priv->mchan[i].chan = &priv->chan[i];
> + priv->mchan[i].id = i;
> + }
> +
> + ret = devm_mbox_controller_register(dev, &priv->mbox);
> + if (ret) {
> + dev_err(dev, "failed to register mailbox: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id sprd_mbox_of_match[] = {
> + { .compatible = "sprd,sc9860-mailbox", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, sprd_mbox_of_match);
> +
> +static struct platform_driver sprd_mbox_driver = {
> + .driver = {
> + .name = "sprd-mailbox",
> + .of_match_table = sprd_mbox_of_match,
> + },
> + .probe = sprd_mbox_probe,
> +};
> +module_platform_driver(sprd_mbox_driver);
> +
> +MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
> +MODULE_DESCRIPTION("Spreadtrum mailbox driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>


--
Baolin Wang

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