Re: [PATCH v5 05/10] soc: qcom: Add AOSS QMP communication driver
On Fri 01 Feb 15:36 PST 2019, Doug Anderson wrote:
> Hi,
>
> On Wed, Jan 30, 2019 at 4:40 PM Bjorn Andersson
> wrote:
> > +++ b/drivers/soc/qcom/aoss-qmp.c
> > @@ -0,0 +1,317 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018, Linaro Ltd
> > + */
> > +#include
> > +#include
> > +#include
> > +#include
> > +#include
> > +#include
> > +
> > +#define QMP_DESC_MAGIC 0x0
> > +#define QMP_DESC_VERSION 0x4
> > +#define QMP_DESC_FEATURES 0x8
> > +
> > +#define QMP_DESC_UCORE_LINK_STATE 0xc
> > +#define QMP_DESC_UCORE_LINK_STATE_ACK 0x10
> > +#define QMP_DESC_UCORE_CH_STATE0x14
> > +#define QMP_DESC_UCORE_CH_STATE_ACK0x18
> > +#define QMP_DESC_UCORE_MBOX_SIZE 0x1c
> > +#define QMP_DESC_UCORE_MBOX_OFFSET 0x20
> > +
> > +#define QMP_DESC_MCORE_LINK_STATE 0x24
> > +#define QMP_DESC_MCORE_LINK_STATE_ACK 0x28
> > +#define QMP_DESC_MCORE_CH_STATE0x2c
> > +#define QMP_DESC_MCORE_CH_STATE_ACK0x30
> > +#define QMP_DESC_MCORE_MBOX_SIZE 0x34
> > +#define QMP_DESC_MCORE_MBOX_OFFSET 0x38
>
> I sure wish something in this file told me what a mcore and a ucore
> were. The only thing I can think of is that an "m" core is two "u"
> cores flipped upside down and placed really close to each other.
> ...if we had 6 upside down "u" cores we'd have an "mmm" core. Mmm,
> core.
>
I had to look at the code again to figure out which side was which, so
I'll add a comment here to indicate which is which.
>
> > +static int qmp_open(struct qmp *qmp)
> > +{
> > + int ret;
> > + u32 val;
> > +
> > + ret = wait_event_timeout(qmp->event, qmp_magic_valid(qmp), HZ);
>
> I'm a totally noob here, but I'm curious: what kicks this event? Do
> we just assume that an IRQ is pending already when the probe()
> function is called? Maybe you could add a comment?
>
> ...or maybe you never actually get an IRQ here and just rely on the
> magic value being right at boot in which case we should just check
> qmp_magic_valid()
>
> ...or maybe you never actually get an IRQ here and this is equivalent
> to msleep(1000) followed by a check of qmp_magic_valid()?
>
This must be me misinterpreting the downstream driver, the magic is
already in place when we enter here.
>
> > + if (!ret) {
> > + dev_err(qmp->dev, "QMP magic doesn't match\n");
> > + return -ETIMEDOUT;
> > + }
> > +
> > + val = readl(qmp->msgram + QMP_DESC_VERSION);
> > + if (val != QMP_VERSION) {
> > + dev_err(qmp->dev, "unsupported QMP version %d\n", val);
> > + return -EINVAL;
> > + }
> > +
> > + qmp->offset = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_OFFSET);
> > + qmp->size = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_SIZE);
> > + if (!qmp->size) {
> > + dev_err(qmp->dev, "invalid mailbox size 0x%zx\n",
> > qmp->size);
>
> nitty nit: Can you do "%#zx" to avoid the need for the 0x?
>
Didn't know I could do that, but that said this is conditional on
!qmp->size, so I'm dropping the 0x0 from the error...
>
> > + return -EINVAL;
> > + }
> > +
> > + /* Ack remote core's link state */
> > + val = readl(qmp->msgram + QMP_DESC_UCORE_LINK_STATE);
> > + writel(val, qmp->msgram + QMP_DESC_UCORE_LINK_STATE_ACK);
> > +
> > + /* Set local core's link state to up */
> > + writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_LINK_STATE);
> > +
> > + qmp_kick(qmp);
> > +
> > + ret = wait_event_timeout(qmp->event, qmp_link_acked(qmp), HZ);
> > + if (!ret) {
> > + dev_err(qmp->dev, "ucore didn't ack link\n");
> > + goto timeout_close_link;
> > + }
> > +
> > + writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_CH_STATE);
> > +
> > + ret = wait_event_timeout(qmp->event, qmp_ucore_channel_up(qmp), HZ);
>
> Again maybe a noob question, but what kicks the interrupt here? Is
> the other side looping waiting to see us write "QMP_STATE_UP" into
> "QMP_DESC_MCORE_CH_STATE" and then it sends us another interrupt?
> ...or are we just getting lucky that the condition is right to begin
> with?
>
I guess it does, but I think there is a kick inbetween here in the
downstream driver, I'll add one for good measure.
>
> > + if (!ret) {
> > + dev_err(qmp->dev, "ucore didn't open channel\n");
> > + goto timeout_close_channel;
> > + }
> > +
> > + /* Ack remote core's channel state */
> > + val = readl(qmp->msgram + QMP_DESC_UCORE_CH_STATE);
> > + writel(val, qmp->msgram + QMP_DESC_UCORE_CH_STATE_ACK);
>
> nit: the readl() is silly here. Just before this you called
> qmp_ucore_channel_up() and that confirmed that the value you're
> getting here is exactly equal to "QMP_STATE_UP". Just write that.
>
Right
>
> > +static int qmp_probe(struct platform_device *pdev)
> > +{
>
Re: [PATCH v5 05/10] soc: qcom: Add AOSS QMP communication driver
Hi,
On Wed, Jan 30, 2019 at 4:40 PM Bjorn Andersson
wrote:
> +++ b/drivers/soc/qcom/aoss-qmp.c
> @@ -0,0 +1,317 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018, Linaro Ltd
> + */
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +#define QMP_DESC_MAGIC 0x0
> +#define QMP_DESC_VERSION 0x4
> +#define QMP_DESC_FEATURES 0x8
> +
> +#define QMP_DESC_UCORE_LINK_STATE 0xc
> +#define QMP_DESC_UCORE_LINK_STATE_ACK 0x10
> +#define QMP_DESC_UCORE_CH_STATE0x14
> +#define QMP_DESC_UCORE_CH_STATE_ACK0x18
> +#define QMP_DESC_UCORE_MBOX_SIZE 0x1c
> +#define QMP_DESC_UCORE_MBOX_OFFSET 0x20
> +
> +#define QMP_DESC_MCORE_LINK_STATE 0x24
> +#define QMP_DESC_MCORE_LINK_STATE_ACK 0x28
> +#define QMP_DESC_MCORE_CH_STATE0x2c
> +#define QMP_DESC_MCORE_CH_STATE_ACK0x30
> +#define QMP_DESC_MCORE_MBOX_SIZE 0x34
> +#define QMP_DESC_MCORE_MBOX_OFFSET 0x38
I sure wish something in this file told me what a mcore and a ucore
were. The only thing I can think of is that an "m" core is two "u"
cores flipped upside down and placed really close to each other.
...if we had 6 upside down "u" cores we'd have an "mmm" core. Mmm,
core.
> +static int qmp_open(struct qmp *qmp)
> +{
> + int ret;
> + u32 val;
> +
> + ret = wait_event_timeout(qmp->event, qmp_magic_valid(qmp), HZ);
I'm a totally noob here, but I'm curious: what kicks this event? Do
we just assume that an IRQ is pending already when the probe()
function is called? Maybe you could add a comment?
...or maybe you never actually get an IRQ here and just rely on the
magic value being right at boot in which case we should just check
qmp_magic_valid()
...or maybe you never actually get an IRQ here and this is equivalent
to msleep(1000) followed by a check of qmp_magic_valid()?
> + if (!ret) {
> + dev_err(qmp->dev, "QMP magic doesn't match\n");
> + return -ETIMEDOUT;
> + }
> +
> + val = readl(qmp->msgram + QMP_DESC_VERSION);
> + if (val != QMP_VERSION) {
> + dev_err(qmp->dev, "unsupported QMP version %d\n", val);
> + return -EINVAL;
> + }
> +
> + qmp->offset = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_OFFSET);
> + qmp->size = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_SIZE);
> + if (!qmp->size) {
> + dev_err(qmp->dev, "invalid mailbox size 0x%zx\n", qmp->size);
nitty nit: Can you do "%#zx" to avoid the need for the 0x?
> + return -EINVAL;
> + }
> +
> + /* Ack remote core's link state */
> + val = readl(qmp->msgram + QMP_DESC_UCORE_LINK_STATE);
> + writel(val, qmp->msgram + QMP_DESC_UCORE_LINK_STATE_ACK);
> +
> + /* Set local core's link state to up */
> + writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_LINK_STATE);
> +
> + qmp_kick(qmp);
> +
> + ret = wait_event_timeout(qmp->event, qmp_link_acked(qmp), HZ);
> + if (!ret) {
> + dev_err(qmp->dev, "ucore didn't ack link\n");
> + goto timeout_close_link;
> + }
> +
> + writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_CH_STATE);
> +
> + ret = wait_event_timeout(qmp->event, qmp_ucore_channel_up(qmp), HZ);
Again maybe a noob question, but what kicks the interrupt here? Is
the other side looping waiting to see us write "QMP_STATE_UP" into
"QMP_DESC_MCORE_CH_STATE" and then it sends us another interrupt?
...or are we just getting lucky that the condition is right to begin
with?
> + if (!ret) {
> + dev_err(qmp->dev, "ucore didn't open channel\n");
> + goto timeout_close_channel;
> + }
> +
> + /* Ack remote core's channel state */
> + val = readl(qmp->msgram + QMP_DESC_UCORE_CH_STATE);
> + writel(val, qmp->msgram + QMP_DESC_UCORE_CH_STATE_ACK);
nit: the readl() is silly here. Just before this you called
qmp_ucore_channel_up() and that confirmed that the value you're
getting here is exactly equal to "QMP_STATE_UP". Just write that.
> +static int qmp_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + struct qmp *qmp;
> + int irq;
> + int ret;
> +
> + qmp = devm_kzalloc(>dev, sizeof(*qmp), GFP_KERNEL);
> + if (!qmp)
> + return -ENOMEM;
> +
> + qmp->dev = >dev;
> + init_waitqueue_head(>event);
> + mutex_init(>tx_lock);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + qmp->msgram = devm_ioremap_resource(>dev, res);
> + if (IS_ERR(qmp->msgram))
> + return PTR_ERR(qmp->msgram);
> +
> + qmp->mbox_client.dev = >dev;
> + qmp->mbox_client.knows_txdone = true;
> + qmp->mbox_chan = mbox_request_channel(>mbox_client, 0);
nit: your code would be simplified a bit if you created
devm_mbox_request_channel() in a prior patch.
