Re: [PATCH v5 1/3] mailbox: Add support for APM X-Gene platform mailbox driver

Mathieu Poirier
2016-02-09T16:40:40Z

On 8 February 2016 at 15:04, Duc Dang <dhdang@apm.com> wrote:
> X-Gene mailbox controller provides 8 mailbox channels, with
> each channel has a dedicated interrupt line.
>
> Signed-off-by: Feng Kan <fkan@apm.com>
> Signed-off-by: Duc Dang <dhdang@apm.com>
> ---
> Changes since v4:
> - Rebase over v4.5-rc1
> - Fix section mistmatch warning by removing
> __init in slimpro_mbox_probe declaration
> - Correctly print channel number when
> there is no IRQ for that channel
>
> Changes since v3:
> - Rebase over v4.4
> - Remove 'id' in slimpro_mbox_chan structure
> - Remove small functions that are only called once
> and fold them into the other callers
> - Remove void* pointer type cast
> - Relax the number of mailbox IRQs condition
> - Use subsys_initcall to guarantee mailbox driver
> will be registered before any other dependent driver
> is loaded.
>
> drivers/mailbox/Kconfig | 9 ++
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/mailbox-xgene-slimpro.c | 264 ++++++++++++++++++++++++++++++++
> 3 files changed, 275 insertions(+)
> create mode 100644 drivers/mailbox/mailbox-xgene-slimpro.c
>
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index 546d05f..678e434 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -85,4 +85,13 @@ config MAILBOX_TEST
> Test client to help with testing new Controller driver
> implementations.
>
> +config XGENE_SLIMPRO_MBOX
> + tristate "APM SoC X-Gene SLIMpro Mailbox Controller"
> + depends on ARCH_XGENE
> + help
> + An implementation of the APM X-Gene Interprocessor Communication
> + Mailbox (IPCM) between the ARM 64-bit cores and SLIMpro controller.
> + It is used to send short messages between ARM64-bit cores and
> + the SLIMpro Management Engine, primarily for PM. Say Y here if you
> + want to use the APM X-Gene SLIMpro IPCM support.
> endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index 92435ef..b602ef8 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -17,3 +17,5 @@ obj-$(CONFIG_ALTERA_MBOX) += mailbox-altera.o
> obj-$(CONFIG_BCM2835_MBOX) += bcm2835-mailbox.o
>
> obj-$(CONFIG_STI_MBOX) += mailbox-sti.o
> +
> +obj-$(CONFIG_XGENE_SLIMPRO_MBOX) += mailbox-xgene-slimpro.o
> diff --git a/drivers/mailbox/mailbox-xgene-slimpro.c b/drivers/mailbox/mailbox-xgene-slimpro.c
> new file mode 100644
> index 0000000..0ea1eb8
> --- /dev/null
> +++ b/drivers/mailbox/mailbox-xgene-slimpro.c
> @@ -0,0 +1,264 @@
> +/*
> + * APM X-Gene SLIMpro MailBox Driver
> + *
> + * Copyright (c) 2015, Applied Micro Circuits Corporation
> + * Author: Feng Kan fkan@apm.com
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +
> +#define MBOX_CON_NAME "slimpro-mbox"
> +#define MBOX_REG_SET_OFFSET 0x1000
> +#define MBOX_CNT 8
> +#define MBOX_STATUS_AVAIL_MASK BIT(16)
> +#define MBOX_STATUS_ACK_MASK BIT(0)
> +
> +/* Configuration and Status Registers */
> +#define REG_DB_IN 0x00
> +#define REG_DB_DIN0 0x04
> +#define REG_DB_DIN1 0x08
> +#define REG_DB_OUT 0x10
> +#define REG_DB_DOUT0 0x14
> +#define REG_DB_DOUT1 0x18
> +#define REG_DB_STAT 0x20
> +#define REG_DB_STATMASK 0x24
> +
> +struct slimpro_mbox_chan {
> + struct device *dev;
> + struct mbox_chan *chan;
> + void __iomem *reg;
> + int irq;
> + u32 rx_msg[3];
> +};
> +
> +struct slimpro_mbox {
> + struct mbox_controller mb_ctrl;
> + struct slimpro_mbox_chan mc[MBOX_CNT];
> + struct mbox_chan chans[MBOX_CNT];
> +};

The above two structure declaration could use kernel style documentation.

> +
> +static void mb_chan_send_msg(struct slimpro_mbox_chan *mb_chan, u32 *msg)
> +{
> + writel(msg[1], mb_chan->reg + REG_DB_DOUT0);
> + writel(msg[2], mb_chan->reg + REG_DB_DOUT1);
> + writel(msg[0], mb_chan->reg + REG_DB_OUT);
> +}
> +
> +static void mb_chan_recv_msg(struct slimpro_mbox_chan *mb_chan)
> +{
> + mb_chan->rx_msg[1] = readl(mb_chan->reg + REG_DB_DIN0);
> + mb_chan->rx_msg[2] = readl(mb_chan->reg + REG_DB_DIN1);
> + mb_chan->rx_msg[0] = readl(mb_chan->reg + REG_DB_IN);
> +}

Is there a requirement that operations in the above two functions be
ordered? If not significant gains could be achieved by using
writel/readl_relaxed(). Same comment for the rest of this driver.

Thanks,
Mathieu

> +
> +static int mb_chan_status_ack(struct slimpro_mbox_chan *mb_chan)
> +{
> + u32 val = readl(mb_chan->reg + REG_DB_STAT);
> +
> + if (val & MBOX_STATUS_ACK_MASK) {
> + writel(MBOX_STATUS_ACK_MASK, mb_chan->reg + REG_DB_STAT);
> + return 1;
> + }
> + return 0;
> +}
> +
> +static int mb_chan_status_avail(struct slimpro_mbox_chan *mb_chan)
> +{
> + u32 val = readl(mb_chan->reg + REG_DB_STAT);
> +
> + if (val & MBOX_STATUS_AVAIL_MASK) {
> + mb_chan_recv_msg(mb_chan);
> + writel(MBOX_STATUS_AVAIL_MASK, mb_chan->reg + REG_DB_STAT);
> + return 1;
> + }
> + return 0;
> +}
> +
> +static irqreturn_t slimpro_mbox_irq(int irq, void *id)
> +{
> + struct slimpro_mbox_chan *mb_chan = id;
> +
> + if (mb_chan_status_ack(mb_chan))
> + mbox_chan_txdone(mb_chan->chan, 0);
> +
> + if (mb_chan_status_avail(mb_chan))
> + mbox_chan_received_data(mb_chan->chan, mb_chan->rx_msg);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int slimpro_mbox_send_data(struct mbox_chan *chan, void *msg)
> +{
> + struct slimpro_mbox_chan *mb_chan = chan->con_priv;
> +
> + mb_chan_send_msg(mb_chan, msg);
> + return 0;
> +}
> +
> +static int slimpro_mbox_startup(struct mbox_chan *chan)
> +{
> + struct slimpro_mbox_chan *mb_chan = chan->con_priv;
> + int rc;
> + u32 val;
> +
> + rc = devm_request_irq(mb_chan->dev, mb_chan->irq, slimpro_mbox_irq, 0,
> + MBOX_CON_NAME, mb_chan);
> + if (unlikely(rc)) {
> + dev_err(mb_chan->dev, "failed to register mailbox interrupt %d\n",
> + mb_chan->irq);
> + return rc;
> + }
> +
> + /* Enable HW interrupt */
> + writel(MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK,
> + mb_chan->reg + REG_DB_STAT);
> + /* Unmask doorbell status interrupt */
> + val = readl(mb_chan->reg + REG_DB_STATMASK);
> + val &= ~(MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK);
> + writel(val, mb_chan->reg + REG_DB_STATMASK);
> +
> + return 0;
> +}
> +
> +static void slimpro_mbox_shutdown(struct mbox_chan *chan)
> +{
> + struct slimpro_mbox_chan *mb_chan = chan->con_priv;
> + u32 val;
> +
> + /* Mask doorbell status interrupt */
> + val = readl(mb_chan->reg + REG_DB_STATMASK);
> + val |= (MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK);
> + writel(val, mb_chan->reg + REG_DB_STATMASK);
> +
> + devm_free_irq(mb_chan->dev, mb_chan->irq, mb_chan);
> +}
> +
> +static struct mbox_chan_ops slimpro_mbox_ops = {
> + .send_data = slimpro_mbox_send_data,
> + .startup = slimpro_mbox_startup,
> + .shutdown = slimpro_mbox_shutdown,
> +};
> +
> +static int slimpro_mbox_probe(struct platform_device *pdev)
> +{
> + struct slimpro_mbox *ctx;
> + struct resource *regs;
> + void __iomem *mb_base;
> + int rc;
> + int i;
> +
> + ctx = devm_kzalloc(&pdev->dev, sizeof(struct slimpro_mbox), GFP_KERNEL);
> + if (IS_ERR(ctx))
> + return PTR_ERR(ctx);
> +
> + platform_set_drvdata(pdev, ctx);
> +
> + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + mb_base = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
> + if (IS_ERR(mb_base))
> + return PTR_ERR(mb_base);
> +
> + /* Setup mailbox links */
> + for (i = 0; i < MBOX_CNT; i++) {
> + ctx->mc[i].irq = platform_get_irq(pdev, i);
> + if (ctx->mc[i].irq < 0) {
> + if (i == 0) {
> + dev_err(&pdev->dev, "no available IRQ\n");
> + return -EINVAL;
> + }
> + dev_info(&pdev->dev, "no IRQ for channel %d\n", i);
> + break;
> + }
> +
> + ctx->mc[i].dev = &pdev->dev;
> + ctx->mc[i].reg = mb_base + i * MBOX_REG_SET_OFFSET;
> + ctx->mc[i].chan = &ctx->chans[i];
> + ctx->chans[i].con_priv = &ctx->mc[i];
> + }
> +
> + /* Setup mailbox controller */
> + ctx->mb_ctrl.dev = &pdev->dev;
> + ctx->mb_ctrl.chans = ctx->chans;
> + ctx->mb_ctrl.txdone_irq = true;
> + ctx->mb_ctrl.ops = &slimpro_mbox_ops;
> + ctx->mb_ctrl.num_chans = i;
> +
> + rc = mbox_controller_register(&ctx->mb_ctrl);
> + if (rc) {
> + dev_err(&pdev->dev,
> + "APM X-Gene SLIMpro MailBox register failed:%d\n", rc);
> + return rc;
> + }
> +
> + dev_info(&pdev->dev, "APM X-Gene SLIMpro MailBox registered\n");
> + return 0;
> +}
> +
> +static int slimpro_mbox_remove(struct platform_device *pdev)
> +{
> + struct slimpro_mbox *smb = platform_get_drvdata(pdev);
> +
> + mbox_controller_unregister(&smb->mb_ctrl);
> + return 0;
> +}
> +
> +static const struct of_device_id slimpro_of_match[] = {
> + {.compatible = "apm,xgene-slimpro-mbox" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, slimpro_of_match);
> +
> +#ifdef CONFIG_ACPI
> +static const struct acpi_device_id slimpro_acpi_ids[] = {
> + {"APMC0D01", 0},
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, slimpro_acpi_ids);
> +#endif
> +
> +static struct platform_driver slimpro_mbox_driver = {
> + .probe = slimpro_mbox_probe,
> + .remove = slimpro_mbox_remove,
> + .driver = {
> + .name = "xgene-slimpro-mbox",
> + .of_match_table = of_match_ptr(slimpro_of_match),
> + .acpi_match_table = ACPI_PTR(slimpro_acpi_ids)
> + },
> +};
> +
> +static int __init slimpro_mbox_init(void)
> +{
> + return platform_driver_register(&slimpro_mbox_driver);
> +}
> +
> +static void __exit slimpro_mbox_exit(void)
> +{
> + platform_driver_unregister(&slimpro_mbox_driver);
> +}
> +
> +subsys_initcall(slimpro_mbox_init);
> +module_exit(slimpro_mbox_exit);
> +
> +MODULE_DESCRIPTION("APM X-Gene SLIMpro Mailbox Driver");
> +MODULE_LICENSE("GPL");
> --
> 1.9.1
>