Re: [PATCH v2 5/8] mailbox: tegra-hsp: Add support for shared mailboxes

From: Jon Hunter
Date: Thu Jun 21 2018 - 04:30:13 EST

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In reply to: Mikko Perttunen: "[PATCH v2 5/8] mailbox: tegra-hsp: Add support for shared mailboxes"
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On 20/06/18 13:20, Mikko Perttunen wrote:
> The Tegra HSP block supports 'shared mailboxes' that are simple 32-bit
> registers consisting of a FULL bit in MSB position and 31 bits of data.
> The hardware can be configured to trigger interrupts when a mailbox
> is empty or full. Add support for these shared mailboxes to the HSP
> driver.
>
> The initial use for the mailboxes is the Tegra Combined UART. For this
> purpose, we use interrupts to receive data, and spinning to wait for
> the transmit mailbox to be emptied to minimize unnecessary overhead.
>
> Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> ---
>
> Notes:
> v2:
> - Added defines for some register fields
> - Simplified bit looping logic in interrupt handler
> - Changed write done polling to use readl_poll_timeout
> - Removed unnecessary zero assignments
> - Fixed two error cases in probe to do proper cleanup
>
> drivers/mailbox/tegra-hsp.c | 210 +++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 190 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/mailbox/tegra-hsp.c b/drivers/mailbox/tegra-hsp.c
> index 5dc21a6d01bb..6864446417c9 100644
> --- a/drivers/mailbox/tegra-hsp.c
> +++ b/drivers/mailbox/tegra-hsp.c
> @@ -13,6 +13,7 @@
>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/mailbox_controller.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> @@ -21,6 +22,13 @@
>
> #include <dt-bindings/mailbox/tegra186-hsp.h>
>
> +#include "mailbox.h"
> +
> +#define HSP_INT0_IE 0x100
> +#define HSP_INT_IR 0x304
> +#define HSP_INT_IR_FULL_SHIFT 8
> +#define HSP_INT_IR_FULL_MASK 0xff
> +
> #define HSP_INT_DIMENSIONING 0x380
> #define HSP_nSM_SHIFT 0
> #define HSP_nSS_SHIFT 4
> @@ -34,6 +42,9 @@
> #define HSP_DB_RAW 0x8
> #define HSP_DB_PENDING 0xc
>
> +#define HSP_SM_SHRD_MBOX 0x0
> +#define HSP_SM_SHRD_MBOX_FULL BIT(31)
> +
> #define HSP_DB_CCPLEX 1
> #define HSP_DB_BPMP 3
> #define HSP_DB_MAX 7
> @@ -68,6 +79,18 @@ struct tegra_hsp_db_map {
> unsigned int index;
> };
>
> +struct tegra_hsp_mailbox {
> + struct tegra_hsp_channel channel;
> + unsigned int index;
> + bool sending;
> +};
> +
> +static inline struct tegra_hsp_mailbox *
> +channel_to_mailbox(struct tegra_hsp_channel *channel)
> +{
> + return container_of(channel, struct tegra_hsp_mailbox, channel);
> +}
> +
> struct tegra_hsp_soc {
> const struct tegra_hsp_db_map *map;
> };
> @@ -77,6 +100,7 @@ struct tegra_hsp {
> struct mbox_controller mbox;
> void __iomem *regs;
> unsigned int doorbell_irq;
> + unsigned int shared_irq;
> unsigned int num_sm;
> unsigned int num_as;
> unsigned int num_ss;
> @@ -85,6 +109,7 @@ struct tegra_hsp {
> spinlock_t lock;
>
> struct list_head doorbells;
> + struct tegra_hsp_mailbox *mailboxes;
> };
>
> static inline struct tegra_hsp *
> @@ -189,6 +214,33 @@ static irqreturn_t tegra_hsp_doorbell_irq(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static irqreturn_t tegra_hsp_shared_irq(int irq, void *data)
> +{
> + struct tegra_hsp_mailbox *mb;
> + struct tegra_hsp *hsp = data;
> + unsigned long bit, mask;
> + u32 value;
> +
> + mask = tegra_hsp_readl(hsp, HSP_INT_IR);
> + /* Only interested in FULL interrupts */
> + mask = (mask >> HSP_INT_IR_FULL_SHIFT) & HSP_INT_IR_FULL_MASK;
> +
> + for_each_set_bit(bit, &mask, 8) {
> + mb = &hsp->mailboxes[bit];
> +
> + if (!mb->sending) {
> + value = tegra_hsp_channel_readl(&mb->channel,
> + HSP_SM_SHRD_MBOX);
> + value &= ~HSP_SM_SHRD_MBOX_FULL;
> + mbox_chan_received_data(mb->channel.chan, &value);
> + tegra_hsp_channel_writel(&mb->channel, value,
> + HSP_SM_SHRD_MBOX);
> + }
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> static struct tegra_hsp_channel *
> tegra_hsp_doorbell_create(struct tegra_hsp *hsp, const char *name,
> unsigned int master, unsigned int index)
> @@ -277,14 +329,57 @@ static void tegra_hsp_doorbell_shutdown(struct tegra_hsp_doorbell *db)
> spin_unlock_irqrestore(&hsp->lock, flags);
> }
>
> +static int tegra_hsp_mailbox_startup(struct tegra_hsp_mailbox *mb)
> +{
> + struct tegra_hsp *hsp = mb->channel.hsp;
> + u32 value;
> +
> + mb->channel.chan->txdone_method = TXDONE_BY_BLOCK;
> +
> + /* Route FULL interrupt to external IRQ 0 */
> + value = tegra_hsp_readl(hsp, HSP_INT0_IE);
> + value |= BIT(mb->index + 8);

Ideally this '8' should be defined as something like HSP_SM_FULL_IRQ_BASE.

> + tegra_hsp_writel(hsp, value, HSP_INT0_IE);
> +
> + return 0;
> +}
> +
> +static int tegra_hsp_mailbox_shutdown(struct tegra_hsp_mailbox *mb)
> +{
> + struct tegra_hsp *hsp = mb->channel.hsp;
> + u32 value;
> +
> + value = tegra_hsp_readl(hsp, HSP_INT0_IE);
> + value &= ~BIT(mb->index + 8);
> + tegra_hsp_writel(hsp, value, HSP_INT0_IE);
> +
> + return 0;
> +}
> +
> static int tegra_hsp_send_data(struct mbox_chan *chan, void *data)
> {
> struct tegra_hsp_channel *channel = chan->con_priv;
> + struct tegra_hsp_mailbox *mailbox;
> + uint32_t value;
>
> switch (channel->type) {
> case TEGRA_HSP_MBOX_TYPE_DB:
> tegra_hsp_channel_writel(channel, 1, HSP_DB_TRIGGER);
> return 0;
> +
> + case TEGRA_HSP_MBOX_TYPE_SM:
> + mailbox = channel_to_mailbox(channel);
> + mailbox->sending = true;
> +
> + value = *(uint32_t *)data;
> + /* Mark mailbox full */
> + value |= HSP_SM_SHRD_MBOX_FULL;
> +
> + tegra_hsp_channel_writel(channel, value, HSP_SM_SHRD_MBOX);
> +
> + return readl_poll_timeout(
> + channel->regs + HSP_SM_SHRD_MBOX, value,
> + !(value & HSP_SM_SHRD_MBOX_FULL), 0, 10000);
> }
>
> return -EINVAL;
> @@ -297,6 +392,8 @@ static int tegra_hsp_startup(struct mbox_chan *chan)
> switch (channel->type) {
> case TEGRA_HSP_MBOX_TYPE_DB:
> return tegra_hsp_doorbell_startup(channel_to_doorbell(channel));
> + case TEGRA_HSP_MBOX_TYPE_SM:
> + return tegra_hsp_mailbox_startup(channel_to_mailbox(channel));
> }
>
> return -EINVAL;
> @@ -310,6 +407,9 @@ static void tegra_hsp_shutdown(struct mbox_chan *chan)
> case TEGRA_HSP_MBOX_TYPE_DB:
> tegra_hsp_doorbell_shutdown(channel_to_doorbell(channel));
> break;
> + case TEGRA_HSP_MBOX_TYPE_SM:
> + tegra_hsp_mailbox_shutdown(channel_to_mailbox(channel));
> + break;
> }
> }
>
> @@ -363,7 +463,16 @@ static struct mbox_chan *of_tegra_hsp_xlate(struct mbox_controller *mbox,
>
> switch (type) {
> case TEGRA_HSP_MBOX_TYPE_DB:
> - return tegra_hsp_doorbell_xlate(hsp, param);
> + if (hsp->doorbell_irq)
> + return tegra_hsp_doorbell_xlate(hsp, param);
> + else
> + return ERR_PTR(-EINVAL);
> +
> + case TEGRA_HSP_MBOX_TYPE_SM:
> + if (hsp->shared_irq && param < hsp->num_sm)
> + return hsp->mailboxes[param].channel.chan;
> + else
> + return ERR_PTR(-EINVAL);
>
> default:
> return ERR_PTR(-EINVAL);
> @@ -402,6 +511,31 @@ static int tegra_hsp_add_doorbells(struct tegra_hsp *hsp)
> return 0;
> }
>
> +static int tegra_hsp_add_mailboxes(struct tegra_hsp *hsp, struct device *dev)
> +{
> + int i;
> +
> + hsp->mailboxes = devm_kcalloc(dev, hsp->num_sm, sizeof(*hsp->mailboxes),
> + GFP_KERNEL);
> + if (!hsp->mailboxes)
> + return -ENOMEM;
> +
> + for (i = 0; i < hsp->num_sm; i++) {
> + struct tegra_hsp_mailbox *mb = &hsp->mailboxes[i];
> +
> + mb->index = i;
> + mb->sending = false;
> +
> + mb->channel.hsp = hsp;
> + mb->channel.type = TEGRA_HSP_MBOX_TYPE_SM;
> + mb->channel.regs = hsp->regs + SZ_64K + i * SZ_32K;
> + mb->channel.chan = &hsp->mbox.chans[i];
> + mb->channel.chan->con_priv = &mb->channel;
> + }
> +
> + return 0;
> +}
> +
> static int tegra_hsp_probe(struct platform_device *pdev)
> {
> struct tegra_hsp *hsp;
> @@ -430,14 +564,15 @@ static int tegra_hsp_probe(struct platform_device *pdev)
> hsp->num_si = (value >> HSP_nSI_SHIFT) & HSP_nINT_MASK;
>
> err = platform_get_irq_byname(pdev, "doorbell");
> - if (err < 0) {
> - dev_err(&pdev->dev, "failed to get doorbell IRQ: %d\n", err);
> - return err;
> - }
> + if (err >= 0)
> + hsp->doorbell_irq = err;
>
> - hsp->doorbell_irq = err;
> + err = platform_get_irq_byname(pdev, "shared0");
> + if (err >= 0)
> + hsp->shared_irq = err;
>
> hsp->mbox.of_xlate = of_tegra_hsp_xlate;
> + /* First nSM are reserved for mailboxes */
> hsp->mbox.num_chans = 32;
> hsp->mbox.dev = &pdev->dev;
> hsp->mbox.txdone_irq = false;
> @@ -450,10 +585,22 @@ static int tegra_hsp_probe(struct platform_device *pdev)
> if (!hsp->mbox.chans)
> return -ENOMEM;
>
> - err = tegra_hsp_add_doorbells(hsp);
> - if (err < 0) {
> - dev_err(&pdev->dev, "failed to add doorbells: %d\n", err);
> - return err;
> + if (hsp->doorbell_irq) {
> + err = tegra_hsp_add_doorbells(hsp);
> + if (err < 0) {
> + dev_err(&pdev->dev, "failed to add doorbells: %d\n",
> + err);
> + return err;
> + }
> + }
> +
> + if (hsp->shared_irq) {
> + err = tegra_hsp_add_mailboxes(hsp, &pdev->dev);
> + if (err < 0) {
> + dev_err(&pdev->dev, "failed to add mailboxes: %d\n",
> + err);
> + goto remove_doorbells;
> + }
> }
>
> platform_set_drvdata(pdev, hsp);
> @@ -461,20 +608,42 @@ static int tegra_hsp_probe(struct platform_device *pdev)
> err = mbox_controller_register(&hsp->mbox);
> if (err) {
> dev_err(&pdev->dev, "failed to register mailbox: %d\n", err);
> - tegra_hsp_remove_doorbells(hsp);
> - return err;
> + goto remove_doorbells;
> }
>
> - err = devm_request_irq(&pdev->dev, hsp->doorbell_irq,
> - tegra_hsp_doorbell_irq, IRQF_NO_SUSPEND,
> - dev_name(&pdev->dev), hsp);
> - if (err < 0) {
> - dev_err(&pdev->dev, "failed to request doorbell IRQ#%u: %d\n",
> - hsp->doorbell_irq, err);
> - return err;
> + if (hsp->doorbell_irq) {
> + err = devm_request_irq(&pdev->dev, hsp->doorbell_irq,
> + tegra_hsp_doorbell_irq, IRQF_NO_SUSPEND,
> + dev_name(&pdev->dev), hsp);
> + if (err < 0) {
> + dev_err(&pdev->dev,
> + "failed to request doorbell IRQ#%u: %d\n",
> + hsp->doorbell_irq, err);
> + goto unregister_mbox_controller;
> + }
> + }
> +
> + if (hsp->shared_irq) {
> + err = devm_request_irq(&pdev->dev, hsp->shared_irq,
> + tegra_hsp_shared_irq, 0,
> + dev_name(&pdev->dev), hsp);
> + if (err < 0) {
> + dev_err(&pdev->dev,
> + "failed to request shared0 IRQ%u: %d\n",
> + hsp->shared_irq, err);
> + goto unregister_mbox_controller;
> + }
> }
>
> return 0;
> +
> +unregister_mbox_controller:
> + mbox_controller_unregister(&hsp->mbox);
> +remove_doorbells:
> + if (hsp->doorbell_irq)
> + tegra_hsp_remove_doorbells(hsp);

This bit looks like it should have been a separate patch to fix the
clean-up if probe fails. However, unless there is a reason to re-spin
the series, probably OK.

> +
> + return err;
> }
>
> static int tegra_hsp_remove(struct platform_device *pdev)
> @@ -482,7 +651,8 @@ static int tegra_hsp_remove(struct platform_device *pdev)
> struct tegra_hsp *hsp = platform_get_drvdata(pdev);
>
> mbox_controller_unregister(&hsp->mbox);
> - tegra_hsp_remove_doorbells(hsp);
> + if (hsp->doorbell_irq)
> + tegra_hsp_remove_doorbells(hsp);
>
> return 0;
> }
>

Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx>

Cheers
Jon

--
nvpublic

Next message: Kai-Heng Feng: "[PATCH net-next v4 1/2] r8169: Don't disable ASPM in the driver"
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In reply to: Mikko Perttunen: "[PATCH v2 5/8] mailbox: tegra-hsp: Add support for shared mailboxes"
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