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Message-ID: <CANLsYkxPnFCuJLyKsHnXKdbvAwNurtgQgJ-WF+bD26+8EjkfJw@mail.gmail.com>
Date: Wed, 10 Feb 2016 07:41:30 -0700
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Duc Dang <dhdang@....com>
Cc: Jassi Brar <jassisinghbrar@...il.com>,
Rob Herring <robh@...nel.org>, Paul Bolle <pebolle@...cali.nl>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
patches <patches@....com>, Feng Kan <fkan@....com>
Subject: Re: [PATCH v5 1/3] mailbox: Add support for APM X-Gene platform
mailbox driver
On 9 February 2016 at 20:46, Duc Dang <dhdang@....com> wrote:
> On Tue, Feb 9, 2016 at 8:40 AM, Mathieu Poirier
> <mathieu.poirier@...aro.org> wrote:
>> On 8 February 2016 at 15:04, Duc Dang <dhdang@....com> wrote:
>>> X-Gene mailbox controller provides 8 mailbox channels, with
>>> each channel has a dedicated interrupt line.
>>>
>>> Signed-off-by: Feng Kan <fkan@....com>
>>> Signed-off-by: Duc Dang <dhdang@....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@....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.
>
> Can you please clarify or give an example? I looked into several files
> in drivers/mailbox/ and drivers/irqchip but could not find what I need
> to tweak.
http://lxr.free-electrons.com/source/drivers/mailbox/mailbox-sti.c#L42
>
>>
>>> +
>>> +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.
>
> The 'writes' need to be in order as writing to REG_DB_OUT will trigger
> interrupt, so I want the other 2 'writes' complete before it.
>
> After the receiver get the message, it will clear door bell available
> interrupt request, this will also trigger a door bell acknowledge
> interrupt. So the 'read' to get the message and the 'write' to clear
> the door bell available interrupt must be in order as well.
>
> Regards,
> Duc Dang.
>>
>> 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
>>>
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