Hi Tzung-Bi,
 
Thanks for your suggestions.
 
 
On Wed, 2021-11-24 at 18:25 +0800, Tzung-Bi Shih wrote:

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On Wed, Nov 24, 2021 at 04:45:13PM +0800, allen-kh.cheng wrote:

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diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index c9fc06c7e685..fc99d9fc80af 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig

@@ -236,6 +236,13 @@ config MTK_CMDQ_MBOX
     critical time limitation, such as updating display

configuration
     during the vblank.
 
+config MTK_ADSP_IPC_MBOX
+  tristate "MediaTek ADSP Mailbox Controller"
+  depends on ARCH_MEDIATEK || COMPILE_TEST
+  help
+    Say yes here to add support for MediaTek ADSP IPC mailbox
controller
+    driver. It is used to send short messages between

processors

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with dsp.

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Although the file didn't maintain alphabetical order, to be neat,
moving MTK_ADSP_IPC_MBOX before MTK_CMDQ_MBOX makes more sense.

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diff --git a/drivers/mailbox/Makefile

b/drivers/mailbox/Makefile

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index c2089f04887e..479a9ae56d5e 100644

--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile

@@ -51,6 +51,8 @@ obj-$(CONFIG_STM32_IPCC)  += stm32-ipcc.o
 
 obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o
 
+obj-$(CONFIG_MTK_ADSP_IPC_MBOX) += mtk-adsp-mailbox.o
+

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Ditto.  Move CONFIG_MTK_ADSP_IPC_MBOX before CONFIG_MTK_CMDQ_MBOX
without blank line separation.

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diff --git a/drivers/mailbox/mtk-adsp-mailbox.c

b/drivers/mailbox/mtk-adsp-mailbox.c

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[...]

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+static irqreturn_t mtk_adsp_ipc_irq_handler(int irq, void

*data)

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+{
+  struct mbox_chan *ch = (struct mbox_chan *)data;

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The cast should be able to remove.

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+static irqreturn_t mtk_adsp_ipc_handler(int irq, void *data)
+{
+  struct mbox_chan *ch = (struct mbox_chan *)data;

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The cast should be able to remove.

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+static int mtk_adsp_mbox_startup(struct mbox_chan *chan)
+{
+  struct adsp_mbox_ch_info *ch_info = chan->con_priv;
+  void __iomem *reg = ch_info->va_reg;
+
+  /* Clear DSP mbox command */
+  writel(0xFFFFFFFF, reg + MTK_ADSP_MBOX_IN_CMD_CLR);
+  writel(0xFFFFFFFF, reg + MTK_ADSP_MBOX_OUT_CMD_CLR);
+
+  return 0;
+}
+
+static void mtk_adsp_mbox_shutdown(struct mbox_chan *chan)
+{
+  chan->con_priv = NULL;
+}

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Shall mtk_adsp_mbox_shutdown() also clear DSP mbox?  I.e.:
writel(0xFFFFFFFF, reg + MTK_ADSP_MBOX_IN_CMD_CLR);
writel(0xFFFFFFFF, reg + MTK_ADSP_MBOX_OUT_CMD_CLR);

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+static int mtk_adsp_mbox_send_data(struct mbox_chan *chan,

void

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*data)
+{
+  struct adsp_mbox_ch_info *ch_info = chan->con_priv;
+  void __iomem *reg = ch_info->va_reg;
+
+  spin_lock(&ch_info->lock);
+  writel(ch_info->ipc_op_val, reg + MTK_ADSP_MBOX_IN_CMD);
+  spin_unlock(&ch_info->lock);

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Why does it need the lock?

Is the write to MTK_ADSP_MBOX_IN_CMD a synchronous operation?
- If yes, I failed to understand why does it need the lock.  Every
calls to mtk_adsp_mbox_send_data() should wait for the data

transfer

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completion.
- If no, I also failed to understand

why.  mtk_adsp_mbox_send_data()

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has no way to be aware of the transfer completion.  Would expect a
loop for checking the completion for the case.

In ADSP MBOX IPC flow,
 
Host would call mbox send data when the shared data transfer completed.
 
(mtk_adsp_mbox_send_data will notice client using MTK_ADSP_MBOX_IN_CMD)
 
It’s more like a signal.
 
In general case,
 
There may be some hosts use the same mbox channel.
 
I think it’s better using lock to protect access to
MTK_ADSP_MBOX_IN_CMD registers
 
 
Thanks,
Allen
 

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+static bool mtk_adsp_mbox_last_tx_done(struct mbox_chan *chan)
+{
+  struct adsp_mbox_ch_info *ch_info = chan->con_priv;
+  void __iomem *reg = ch_info->va_reg;
+  u32 op = readl(reg + MTK_ADSP_MBOX_IN_CMD);
+
+  return (op == 0) ? true : false;

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To be concise, return readl(...) == 0;

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+static int mtk_adsp_mbox_probe(struct platform_device *pdev)
+{

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[...]

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+  res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+  if (!res) {
+      dev_err(dev, "no adsp mbox register resource\n");
+      return -ENXIO;
+  }
+
+  size = resource_size(res);
+  priv->va_mboxreg = devm_ioremap(dev, (phys_addr_t)res-

start,

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size);
+  if (IS_ERR(priv->va_mboxreg))
+      return PTR_ERR(priv->va_mboxreg);

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Use devm_platform_ioremap_resource(), it should be equivalent.

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+  /* set adsp mbox channel info */
+  ch_info = devm_kzalloc(mbox->dev, sizeof(*ch_info),
GFP_KERNEL);

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To be neat, use dev instead of mbox->dev.

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+  ret = devm_mbox_controller_register(dev, &priv->mbox);
+  if (ret < 0)
+      dev_err(dev, "error: failed to register mailbox:%d\n",
ret);
+
+  return ret;

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To be concise, return devm_mbox_controller_register(...);

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