Hi Oleksij,
On 07/18/2018 10:12 AM, Oleksij Rempel wrote:
> The Mailbox controller is able to send messages (up to 4 32 bit words)
> between the endpoints.
>
> This driver was tested using the mailbox-test driver sending messages
> between the Cortex-A7 and the Cortex-M4.
>
> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> ---
> drivers/mailbox/Kconfig | 6 +
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/imx-mailbox.c | 300 ++++++++++++++++++++++++++++++++++
> 3 files changed, 308 insertions(+)
> create mode 100644 drivers/mailbox/imx-mailbox.c
>
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index a2bb27446dce..79060ddc380d 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -15,6 +15,12 @@ config ARM_MHU
> The controller has 3 mailbox channels, the last of which can be
> used in Secure mode only.
>
> +config IMX_MBOX
> + tristate "i.MX Mailbox"
> + depends on ARCH_MXC || COMPILE_TEST
> + help
> + Mailbox implementation for i.MX Messaging Unit (MU).
> +
> config PLATFORM_MHU
> tristate "Platform MHU Mailbox"
> depends on OF
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index cc23c3a43fcd..ba2fe1b6dd62 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -7,6 +7,8 @@ obj-$(CONFIG_MAILBOX_TEST) += mailbox-test.o
>
> obj-$(CONFIG_ARM_MHU) += arm_mhu.o
>
> +obj-$(CONFIG_IMX_MBOX) += imx-mailbox.o
> +
> obj-$(CONFIG_PLATFORM_MHU) += platform_mhu.o
>
> obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o
> diff --git a/drivers/mailbox/imx-mailbox.c b/drivers/mailbox/imx-mailbox.c
> new file mode 100644
> index 000000000000..ad8797127b1f
> --- /dev/null
> +++ b/drivers/mailbox/imx-mailbox.c
> @@ -0,0 +1,300 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/clk.h>
> +#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>
> +
> +/* Transmit Register */
> +#define IMX_MU_xTRn(x) (0x00 + 4 * (x))
> +/* Receive Register */
> +#define IMX_MU_xRRn(x) (0x10 + 4 * (x))
> +/* Status Register */
> +#define IMX_MU_xSR 0x20
> +#define IMX_MU_xSR_TEn(x) BIT(20 + (3 - (x)))
> +#define IMX_MU_xSR_RFn(x) BIT(24 + (3 - (x)))
> +#define IMX_MU_xSR_BRDIP BIT(9)
> +
> +/* Control Register */
> +#define IMX_MU_xCR 0x24
> +/* Transmit Interrupt Enable */
> +#define IMX_MU_xCR_TIEn(x) BIT(20 + (3 - (x)))
> +/* Receive Interrupt Enable */
> +#define IMX_MU_xCR_RIEn(x) BIT(24 + (3 - (x)))
> +
> +#define IMX_MU_MAX_CHANS 4u
> +
> +struct imx_mu_priv;
> +
> +struct imx_mu_cfg {
> + unsigned int chans;
Basically this field is not used, everywhere in the driver its usage can
be replaced by IMX_MU_MAX_CHANS, and it makes sense to rename the latter,
and 'chan' local variable from .probe is also removed.
I suggest that you add this field at the time when you to add controller
specific data other than 'imx_mu_cfg_generic'.
> + void (*init_hw)(struct imx_mu_priv *priv);
> +};
> +
> +struct imx_mu_con_priv {
> + int irq;
> + unsigned int idx;
> + char *irq_desc;
> +};
> +
> +struct imx_mu_priv {
> + struct device *dev;
> + const struct imx_mu_cfg *dcfg;
> + void __iomem *base;
> +
> + struct mbox_controller mbox;
> + struct mbox_chan mbox_chans[IMX_MU_MAX_CHANS];
> +
> + struct imx_mu_con_priv con_priv[IMX_MU_MAX_CHANS];
> + struct clk *clk;
> +
> + bool side_b;
> +};
> +
> +static struct imx_mu_priv *to_imx_mu_priv(struct mbox_controller *mbox)
> +{
> + return container_of(mbox, struct imx_mu_priv, mbox);
> +}
> +
> +static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs)
> +{
> + iowrite32(val, priv->base + offs);
> +}
> +
> +static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs)
> +{
> + return ioread32(priv->base + offs);
> +}
> +
> +static u32 imx_mu_rmw(struct imx_mu_priv *priv, u32 offs, u32 set, u32 clr)
> +{
> + u32 val;
> +
> + val = imx_mu_read(priv, offs);
> + val &= ~clr;
> + val |= set;
> + imx_mu_write(priv, val, offs);
> +
> + return val;
> +}
> +
> +static irqreturn_t imx_mu_isr(int irq, void *p)
> +{
> + struct mbox_chan *chan = p;
> + struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> + struct imx_mu_con_priv *cp = chan->con_priv;
> + u32 val, ctrl, dat;
> +
> + ctrl = imx_mu_read(priv, IMX_MU_xCR);
> + val = imx_mu_read(priv, IMX_MU_xSR);
> + val &= IMX_MU_xSR_TEn(cp->idx) | IMX_MU_xSR_RFn(cp->idx);
> + val &= ctrl & (IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
> + if (!val)
> + return IRQ_NONE;
> +
> + if (val & IMX_MU_xSR_TEn(cp->idx)) {
> + imx_mu_rmw(priv, IMX_MU_xCR, 0, IMX_MU_xCR_TIEn(cp->idx));
> + mbox_chan_txdone(chan, 0);
> + }
> +
> + if (val & IMX_MU_xSR_RFn(cp->idx)) {
> + dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
> + mbox_chan_received_data(chan, (void *)&dat);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static bool imx_mu_last_tx_done(struct mbox_chan *chan)
> +{
> + struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> + struct imx_mu_con_priv *cp = chan->con_priv;
> + u32 val;
> +
> + val = imx_mu_read(priv, IMX_MU_xSR);
> + /* test if transmit register is empty */
> + return (!!(val & IMX_MU_xSR_TEn(cp->idx)));
Because the function returns bool value, double negation is not needed.
return val & IMX_MU_xSR_TEn(cp->idx);
is good enough.
> +}
> +
> +static int imx_mu_send_data(struct mbox_chan *chan, void *data)
> +{
> + struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> + struct imx_mu_con_priv *cp = chan->con_priv;
> + u32 *arg = data;
> +
> + if (!imx_mu_last_tx_done(chan))
> + return -EBUSY;
> +
> + imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
> + imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xSR_TEn(cp->idx), 0);
> +
> + return 0;
> +}
> +
> +static int imx_mu_startup(struct mbox_chan *chan)
> +{
> + struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> + struct imx_mu_con_priv *cp = chan->con_priv;
> + int ret;
> +
> + cp->irq_desc = devm_kasprintf(priv->dev, GFP_KERNEL, "imx_mu_chan[%i]",
> + cp->idx);
> + if (!cp->irq_desc)
> + return -ENOMEM;
> +
> + ret = devm_request_irq(priv->dev, cp->irq, imx_mu_isr,
> + IRQF_SHARED, cp->irq_desc, chan);
> + if (ret) {
> + dev_err(priv->dev,
> + "Unable to acquire IRQ %d\n", cp->irq);
> + return ret;
> + }
> +
> + imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xCR_RIEn(cp->idx), 0);
> +
> + return 0;
> +}
> +
> +static void imx_mu_shutdown(struct mbox_chan *chan)
> +{
> + struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> + struct imx_mu_con_priv *cp = chan->con_priv;
> +
> + imx_mu_rmw(priv, IMX_MU_xCR, 0,
> + IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
> +
> + devm_free_irq(priv->dev, cp->irq, chan);
> + devm_kfree(priv->dev, cp->irq_desc);
> +}
> +
> +static const struct mbox_chan_ops imx_mu_ops = {
> + .send_data = imx_mu_send_data,
> + .startup = imx_mu_startup,
> + .shutdown = imx_mu_shutdown,
> +};
> +
> +static int imx_mu_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct resource *iomem;
> + struct imx_mu_priv *priv;
> + const struct imx_mu_cfg *dcfg;
> + unsigned int i, chans;
> + int irq, ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + dcfg = of_device_get_match_data(dev);
> + if (!dcfg)
> + return -EINVAL;
> +
> + priv->dcfg = dcfg;
> + priv->dev = dev;
> +
> + iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + priv->base = devm_ioremap_resource(&pdev->dev, iomem);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq <= 0)
> + return irq < 0 ? irq : -EINVAL;
Please don't check or handle 'irq == 0' case specially, it is dead code.
if (irq < 0)
return irq;
is good enough.
> +
> + priv->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(priv->clk)) {
> + if (PTR_ERR(priv->clk) != -ENOENT)
> + return PTR_ERR(priv->clk);
> +
> + priv->clk = NULL;
> + }
> +
> + ret = clk_prepare_enable(priv->clk);
> + if (ret) {
> + dev_err(dev, "Failed to enable clock\n");
> + return ret;
> + }
> +
> + chans = min(dcfg->chans, IMX_MU_MAX_CHANS);
> + /* Initialize channel identifiers */
The comment above is trivial, please remove it.
> + for (i = 0; i < chans; i++) {
> + struct imx_mu_con_priv *cp = &priv->con_priv[i];
> +
> + cp->idx = i;
> + cp->irq = irq;
I read it as a single irq for all channels.
Why do you dynamically init more channel data imx_mu_startup() based on irq value?
Aren't 'cp->irq_desc' all equal? Isn't just a single devm_request_irq() in .probe
sufficient?
> + priv->mbox_chans[i].con_priv = cp;
> + }
> +
> + if (of_property_read_bool(np, "fsl,mu-side-b"))
> + priv->side_b = true;
> +
> + priv->mbox.dev = dev;
> + priv->mbox.ops = &imx_mu_ops;
> + priv->mbox.chans = priv->mbox_chans;
> + priv->mbox.num_chans = chans;
> + priv->mbox.txdone_irq = true;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + if (priv->dcfg->init_hw)
> + priv->dcfg->init_hw(priv);
> +
> + return mbox_controller_register(&priv->mbox);
> +}
> +
> +static int imx_mu_remove(struct platform_device *pdev)
> +{
> + struct imx_mu_priv *priv = platform_get_drvdata(pdev);
> +
> + mbox_controller_unregister(&priv->mbox);
> + clk_disable_unprepare(priv->clk);
> +
> + return 0;
> +}
> +
> +static void imx_mu_init_generic(struct imx_mu_priv *priv)
> +{
> + if (priv->side_b)
> + return;
> +
> + /* Set default MU configuration */
> + imx_mu_write(priv, 0, IMX_MU_xCR);
> +}
> +
> +static const struct imx_mu_cfg imx_mu_cfg_generic = {
> + .chans = IMX_MU_MAX_CHANS,
Here IMX_MU_MAX_CHANS macro name is questionable, see my top comment.
For clarity here 'MAX' is not expected, it shall be the exact controller
specific value, something like s/MAX/NUM/ may be considered.
> + .init_hw = imx_mu_init_generic,
> +};
> +
> +static const struct of_device_id imx_mu_dt_ids[] = {
> + { .compatible = "fsl,imx6sx-mu", .data = &imx_mu_cfg_generic },
> + { .compatible = "fsl,imx7d-mu", .data = &imx_mu_cfg_generic },
> + { .compatible = "fsl,imx7s-mu", .data = &imx_mu_cfg_generic },
> + { .compatible = "fsl,imx7ulp-mu", .data = &imx_mu_cfg_generic },
> + { .compatible = "fsl,imx8qm-mu", .data = &imx_mu_cfg_generic },
> + { .compatible = "fsl,imx8qxp-mu", .data = &imx_mu_cfg_generic },
It sounds like the list will be constantly extending. Is there any chance
to introduce just one generic compatible in the driver, and describe
the whole set of compatibles in documentation section only?
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);
> +
> +static struct platform_driver imx_mu_driver = {
> + .probe = imx_mu_probe,
> + .remove = imx_mu_remove,
> + .driver = {
> + .name = "imx_mu",
> + .of_match_table = imx_mu_dt_ids,
> + },
> +};
> +module_platform_driver(imx_mu_driver);
> +
> +MODULE_AUTHOR("Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Message Unit driver for i.MX");
> +MODULE_LICENSE("GPL v2");
>
--
Best wishes,
Vladimir
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