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Message-ID: <037f6cea-28c7-4114-b542-7f12aa1bcb1f@quicinc.com>
Date: Thu, 17 Oct 2024 17:22:36 +0530
From: Shivnandan Kumar <quic_kshivnan@...cinc.com>
To: Bjorn Andersson <andersson@...nel.org>
CC: Sibi Sankar <quic_sibis@...cinc.com>,
Jassi Brar
<jassisinghbrar@...il.com>, Rob Herring <robh@...nel.org>,
"Krzysztof
Kozlowski" <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
<cros-qcom-dts-watchers@...omium.org>,
Konrad Dybcio
<konradybcio@...nel.org>,
<linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<devicetree@...r.kernel.org>,
"Ramakrishna
Gottimukkula" <quic_rgottimu@...cinc.com>
Subject: Re: [PATCH 2/3] mailbox: qcom-cpucp-mbox: Add support for SC7280
CPUCP mailbox controller
Thank you, Bjorn, for taking the time to review this patch series.
On 10/6/2024 8:03 AM, Bjorn Andersson wrote:
> On Tue, Sep 24, 2024 at 10:39:40AM GMT, Shivnandan Kumar wrote:
>> The SC7280 CPUCP mailbox controller is compatible with legacy mailbox
>> hardware.
>
> "mailbox hardware" is a very vague description of something.
>
>> Implement support for this functionality which enable HLOS to
>> CPUCP communication.
>>
>
> Please describe the problem that this solves. What "legacy mailbox
> hardware"? Why do you want to talk to the CPUCP? What is a HLOS? What
> is the CPUCP?
>
ACK, I will add description in next patch series.
> It seems from the patch that the current implementation supports
> something we call "version 2" of the cpucp mailbox interface and you're
> adding support for v1. Please make sure that the commit message describe
> such things.
>
ACK
>> Signed-off-by: Shivnandan Kumar <quic_kshivnan@...cinc.com>
>> ---
>> drivers/mailbox/qcom-cpucp-mbox.c | 156 +++++++++++++++++++++++-------
>> 1 file changed, 122 insertions(+), 34 deletions(-)
>>
>> diff --git a/drivers/mailbox/qcom-cpucp-mbox.c b/drivers/mailbox/qcom-cpucp-mbox.c
>> index e5437c294803..faae6e069ea1 100644
>> --- a/drivers/mailbox/qcom-cpucp-mbox.c
>> +++ b/drivers/mailbox/qcom-cpucp-mbox.c
>> @@ -13,18 +13,24 @@
>> #include <linux/platform_device.h>
>>
>> #define APSS_CPUCP_IPC_CHAN_SUPPORTED 3
>> -#define APSS_CPUCP_MBOX_CMD_OFF 0x4
>> -
>> -/* Tx Registers */
>> -#define APSS_CPUCP_TX_MBOX_CMD(i) (0x100 + ((i) * 8))
>>
>> /* Rx Registers */
>> -#define APSS_CPUCP_RX_MBOX_CMD(i) (0x100 + ((i) * 8))
>> -#define APSS_CPUCP_RX_MBOX_MAP 0x4000
>> -#define APSS_CPUCP_RX_MBOX_STAT 0x4400
>> -#define APSS_CPUCP_RX_MBOX_CLEAR 0x4800
>> -#define APSS_CPUCP_RX_MBOX_EN 0x4c00
>> -#define APSS_CPUCP_RX_MBOX_CMD_MASK GENMASK_ULL(63, 0)
>> +#define APSS_CPUCP_V2_RX_MBOX_CMD_MASK GENMASK_ULL(63, 0)
>> +#define APSS_CPUCP_V1_SEND_IRQ_VAL BIT(28)
>> +#define APSS_CPUCP_V1_CLEAR_IRQ_VAL BIT(3)
>> +#define APSS_CPUCP_V1_STATUS_IRQ_VAL BIT(3)
>> +
>> +struct qcom_cpucp_mbox_desc {
>> + u32 enable_reg;
>
> Do you really need these parameters to be dynamic? E.g. you only touch
> enable_reg from the v2 code paths...
>
Will remove this in next patch series.
>> + u32 map_reg;
>> + u32 rx_reg;
>> + u32 tx_reg;
>> + u32 status_reg;
>> + u32 clear_reg;
>> + u32 chan_stride;
>
> "u32" tells me that this has to be 32 bits, e.g. because the value is
> going into a register... But these are just offsets...
>
> Please use "unsigned int" to denote "a natural number".
>
ACK
>> + bool v2_mbox;
>
> How about "version" and give it a value 1 or 2?
>
Ok, will do like that.
>> + u32 num_chans;
>> +};
>>
>> /**
>> * struct qcom_cpucp_mbox - Holder for the mailbox driver
>> @@ -35,6 +41,7 @@
>> */
>> struct qcom_cpucp_mbox {
>> struct mbox_chan chans[APSS_CPUCP_IPC_CHAN_SUPPORTED];
>> + const struct qcom_cpucp_mbox_desc *desc;
>> struct mbox_controller mbox;
>> void __iomem *tx_base;
>> void __iomem *rx_base;
>> @@ -48,13 +55,40 @@ static inline int channel_number(struct mbox_chan *chan)
>> static irqreturn_t qcom_cpucp_mbox_irq_fn(int irq, void *data)
>
> Why is the existing function renamed "v2" and this newly introduced
> function not given a version?
>
ACK
>> {
>> struct qcom_cpucp_mbox *cpucp = data;
>> + const struct qcom_cpucp_mbox_desc *desc = cpucp->desc;
>> + int i;
>> +
>> + for (i = 0; i < desc->num_chans; i++) {
>> + u32 val = readl(cpucp->rx_base + desc->status_reg + (i * desc->chan_stride));
>> + struct mbox_chan *chan = &cpucp->chans[i];
>> + unsigned long flags;
>> +
>> + if (val & APSS_CPUCP_V1_STATUS_IRQ_VAL) {
>> + writel(APSS_CPUCP_V1_CLEAR_IRQ_VAL,
>> + cpucp->rx_base + desc->clear_reg + (i * desc->chan_stride));
>> + /* Make sure reg write is complete before proceeding */
>> + mb();
>> + spin_lock_irqsave(&chan->lock, flags);
>> + if (chan->cl)
>> + mbox_chan_received_data(chan, NULL);
>> + spin_unlock_irqrestore(&chan->lock, flags);
>> + }
>> + }
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t qcom_cpucp_v2_mbox_irq_fn(int irq, void *data)
>> +{
>> + struct qcom_cpucp_mbox *cpucp = data;
>> + const struct qcom_cpucp_mbox_desc *desc = cpucp->desc;
>> u64 status;
>> int i;
>>
>> - status = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_STAT);
>> + status = readq(cpucp->rx_base + desc->status_reg);
>>
>> - for_each_set_bit(i, (unsigned long *)&status, APSS_CPUCP_IPC_CHAN_SUPPORTED) {
>> - u32 val = readl(cpucp->rx_base + APSS_CPUCP_RX_MBOX_CMD(i) + APSS_CPUCP_MBOX_CMD_OFF);
>> + for_each_set_bit(i, (unsigned long *)&status, desc->num_chans) {
>> + u32 val = readl(cpucp->rx_base + desc->rx_reg + (i * desc->chan_stride));
>> struct mbox_chan *chan = &cpucp->chans[i];
>> unsigned long flags;
>>
>> @@ -62,7 +96,7 @@ static irqreturn_t qcom_cpucp_mbox_irq_fn(int irq, void *data)
>> spin_lock_irqsave(&chan->lock, flags);
>> if (chan->cl)
>> mbox_chan_received_data(chan, &val);
>> - writeq(BIT(i), cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
>> + writeq(BIT(i), cpucp->rx_base + desc->clear_reg);
>> spin_unlock_irqrestore(&chan->lock, flags);
>> }
>>
>> @@ -72,12 +106,15 @@ static irqreturn_t qcom_cpucp_mbox_irq_fn(int irq, void *data)
>> static int qcom_cpucp_mbox_startup(struct mbox_chan *chan)
>> {
>> struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
>> + const struct qcom_cpucp_mbox_desc *desc = cpucp->desc;
>> unsigned long chan_id = channel_number(chan);
>> u64 val;
>>
>> - val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
>> - val |= BIT(chan_id);
>> - writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
>> + if (desc->v2_mbox) {
>> + val = readq(cpucp->rx_base + desc->enable_reg);
>> + val |= BIT(chan_id);
>> + writeq(val, cpucp->rx_base + desc->enable_reg);
>> + }
>
> No equivalent in "legacy"?
Yes, right
>>
>> return 0;
>> }
>> @@ -85,22 +122,26 @@ static int qcom_cpucp_mbox_startup(struct mbox_chan *chan)
>> static void qcom_cpucp_mbox_shutdown(struct mbox_chan *chan)
>> {
>> struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
>> + const struct qcom_cpucp_mbox_desc *desc = cpucp->desc;
>> unsigned long chan_id = channel_number(chan);
>> u64 val;
>>
>> - val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
>> - val &= ~BIT(chan_id);
>> - writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
>> + if (desc->v2_mbox) {
>> + val = readq(cpucp->rx_base + desc->enable_reg);
>> + val &= ~BIT(chan_id);
>> + writeq(val, cpucp->rx_base + desc->enable_reg);
>> + }
>
> Ditto
>
We do not have equivalent in "legacy".
>> }
>>
>> static int qcom_cpucp_mbox_send_data(struct mbox_chan *chan, void *data)
>> {
>> struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
>> + const struct qcom_cpucp_mbox_desc *desc = cpucp->desc;
>> + u32 val = desc->v2_mbox ? *(u32 *)data : APSS_CPUCP_V1_SEND_IRQ_VAL;
>
> Please rewrite this without ternary operators.
>
ACK
>> unsigned long chan_id = channel_number(chan);
>> - u32 *val = data;
>> -
>> - writel(*val, cpucp->tx_base + APSS_CPUCP_TX_MBOX_CMD(chan_id) + APSS_CPUCP_MBOX_CMD_OFF);
>> + u32 offset = desc->v2_mbox ? (chan_id * desc->chan_stride) : 0;
>>
>> + writel(val, cpucp->tx_base + desc->tx_reg + offset);
>> return 0;
>> }
>>
>> @@ -112,41 +153,66 @@ static const struct mbox_chan_ops qcom_cpucp_mbox_chan_ops = {
>>
>> static int qcom_cpucp_mbox_probe(struct platform_device *pdev)
>> {
>> + const struct qcom_cpucp_mbox_desc *desc;
>> struct device *dev = &pdev->dev;
>> struct qcom_cpucp_mbox *cpucp;
>> struct mbox_controller *mbox;
>> + struct resource *res;
>> int irq, ret;
>>
>> + desc = device_get_match_data(&pdev->dev);
>> + if (!desc)
>> + return -EINVAL;
>> +
>> cpucp = devm_kzalloc(dev, sizeof(*cpucp), GFP_KERNEL);
>> if (!cpucp)
>> return -ENOMEM;
>>
>> - cpucp->rx_base = devm_of_iomap(dev, dev->of_node, 0, NULL);
>> - if (IS_ERR(cpucp->rx_base))
>> - return PTR_ERR(cpucp->rx_base);
>> + cpucp->desc = desc;
>> +
>> + if (desc->v2_mbox) {
>> + cpucp->rx_base = devm_of_iomap(dev, dev->of_node, 0, NULL);
>> + if (IS_ERR(cpucp->rx_base))
>> + return PTR_ERR(cpucp->rx_base);
>> + /* Legacy mailbox quirks due to shared region with EPSS register space */
>
> Why can't we have the same code in both cases?
>
RX address space share region with EPSS. Due to which devm_of_iomap
returns -EBUSY.
>> + } else {
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res) {
>> + dev_err(&pdev->dev, "Failed to get the device base address\n");
>
> It's not only base address.
>
Will add appropriate print statement.
>> + return -ENODEV;
>> + }
>> + cpucp->rx_base = devm_ioremap(dev, res->start, resource_size(res));
>> + if (!cpucp->rx_base) {
>> + dev_err(dev, "Failed to ioremap the cpucp rx irq addr\n");
>> + return -ENOMEM;
>> + }
>> + }
>>
>> cpucp->tx_base = devm_of_iomap(dev, dev->of_node, 1, NULL);
>> if (IS_ERR(cpucp->tx_base))
>> return PTR_ERR(cpucp->tx_base);
>>
>> - writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
>> - writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
>> - writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
>> + if (desc->v2_mbox) {
>> + writeq(0, cpucp->rx_base + desc->enable_reg);
>> + writeq(0, cpucp->rx_base + desc->clear_reg);
>> + writeq(0, cpucp->rx_base + desc->map_reg);
>
>
> Is there a reason why the legacy system does not need or want to clear
> these?
>
Legacy system does not have equivalent registers.
>> + }
>>
>> irq = platform_get_irq(pdev, 0);
>> if (irq < 0)
>> return irq;
>>
>> - ret = devm_request_irq(dev, irq, qcom_cpucp_mbox_irq_fn,
>> - IRQF_TRIGGER_HIGH, "apss_cpucp_mbox", cpucp);
>> + ret = devm_request_irq(dev, irq, desc->v2_mbox ? qcom_cpucp_v2_mbox_irq_fn :
>> + qcom_cpucp_mbox_irq_fn, IRQF_TRIGGER_HIGH, "apss_cpucp_mbox", cpucp);
>
> The use of a ternary operator, in combination with odd line wrapping
> makes this completely unreadable. Please fix.
>
ACK
>> if (ret < 0)
>> return dev_err_probe(dev, ret, "Failed to register irq: %d\n", irq);
>>
>> - writeq(APSS_CPUCP_RX_MBOX_CMD_MASK, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
>> + if (desc->v2_mbox)
>> + writeq(APSS_CPUCP_V2_RX_MBOX_CMD_MASK, cpucp->rx_base + desc->map_reg);
>>
>> mbox = &cpucp->mbox;
>> mbox->dev = dev;
>> - mbox->num_chans = APSS_CPUCP_IPC_CHAN_SUPPORTED;
>> + mbox->num_chans = desc->num_chans;
>> mbox->chans = cpucp->chans;
>> mbox->ops = &qcom_cpucp_mbox_chan_ops;
>>
>> @@ -157,8 +223,30 @@ static int qcom_cpucp_mbox_probe(struct platform_device *pdev)
>> return 0;
>> }
>>
>> +static const struct qcom_cpucp_mbox_desc sc7280_cpucp_mbox = {
>> + .tx_reg = 0xC,
>> + .chan_stride = 0x1000,
>> + .status_reg = 0x30C,
>
> Lowercase hex digits please (although the question above whether these
> needs to be defined remains).
ACK
>
>> + .clear_reg = 0x308,
>> + .v2_mbox = false,
>> + .num_chans = 2,
>> +};
>> +
>> +static const struct qcom_cpucp_mbox_desc x1e80100_cpucp_mbox = {
>> + .rx_reg = 0x104,
>> + .tx_reg = 0x104,
>> + .chan_stride = 0x8,
>> + .map_reg = 0x4000,
>> + .status_reg = 0x4400,
>> + .clear_reg = 0x4800,
>> + .enable_reg = 0x4C00,
>> + .v2_mbox = true,
>> + .num_chans = 3,
>> +};
>> +
>> static const struct of_device_id qcom_cpucp_mbox_of_match[] = {
>> - { .compatible = "qcom,x1e80100-cpucp-mbox" },
>> + { .compatible = "qcom,x1e80100-cpucp-mbox", .data = &x1e80100_cpucp_mbox},
>> + { .compatible = "qcom,sc7280-cpucp-mbox", .data = &sc7280_cpucp_mbox},
>
> Perhaps I'm missing something, but seems like the only information you
> actually need to pass here is 1 or 2, to denote which version/code paths
> you should take through the driver.
>
okay, I will rename sc7280_cpucp_mbox and x1e80100_cpucp_mbox structures
as v1 and v2 respectively.
> Regards,
> Bjorn
>
>> {}
>> };
>> MODULE_DEVICE_TABLE(of, qcom_cpucp_mbox_of_match);
>> --
>> 2.25.1
>>
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