bus: mhi: ep: Add async read/write support

[PATCH 4/9] PCI: epf-mhi: Simulate async read/write using iATU

Posted by Manivannan Sadhasivam 2 years ago

Even though iATU only supports synchronous read/write, the MHI stack may
call async read/write callbacks without knowing the limitations of the
controller driver. So in order to maintain compatibility, let's simulate
async read/write operation with iATU by invoking the completion callback
after memcpy.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/pci/endpoint/functions/pci-epf-mhi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
index 34e7191f9508..7214f4da733b 100644
--- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -234,6 +234,9 @@ static int pci_epf_mhi_iatu_read(struct mhi_ep_cntrl *mhi_cntrl,
 
 	mutex_unlock(&epf_mhi->lock);
 
+	if (buf_info->cb)
+		buf_info->cb(buf_info);
+
 	return 0;
 }
 
@@ -262,6 +265,9 @@ static int pci_epf_mhi_iatu_write(struct mhi_ep_cntrl *mhi_cntrl,
 
 	mutex_unlock(&epf_mhi->lock);
 
+	if (buf_info->cb)
+		buf_info->cb(buf_info);
+
 	return 0;
 }
 
-- 
2.25.1

Re: [PATCH 4/9] PCI: epf-mhi: Simulate async read/write using iATU

Posted by Krzysztof Wilczyński 2 years ago

Hello,

> Even though iATU only supports synchronous read/write, the MHI stack may
> call async read/write callbacks without knowing the limitations of the
> controller driver. So in order to maintain compatibility, let's simulate
> async read/write operation with iATU by invoking the completion callback
> after memcpy.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/endpoint/functions/pci-epf-mhi.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
> index 34e7191f9508..7214f4da733b 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
> @@ -234,6 +234,9 @@ static int pci_epf_mhi_iatu_read(struct mhi_ep_cntrl *mhi_cntrl,
>  
>  	mutex_unlock(&epf_mhi->lock);
>  
> +	if (buf_info->cb)
> +		buf_info->cb(buf_info);
> +
>  	return 0;
>  }
>  
> @@ -262,6 +265,9 @@ static int pci_epf_mhi_iatu_write(struct mhi_ep_cntrl *mhi_cntrl,
>  
>  	mutex_unlock(&epf_mhi->lock);
>  
> +	if (buf_info->cb)
> +		buf_info->cb(buf_info);
> +
>  	return 0;
>  }

Looks good!

Reviewed-by: Krzysztof Wilczyński <kw@linux.com>

	Krzysztof