From: Macpaul Lin <macpaul.lin@mediatek.com> Date: 2020-06-16 12:35:00
Some USB hardware like DMA engine can help to process (split) the data
of each URB request into small packets. For example, the max packet size
of high speed is 512 bytes. These kinds of hardware can help to split
the continue Tx/Rx data requests into packets just at the max packet
size during transmission. Hence upper layer software can reduce some
effort for queueing many requests back and forth for larger data.
Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
hardware is ready to support these operations.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/mtu3/mtu3_qmu.c | 11 ++++++++++-
include/linux/usb/gadget.h | 1 +
2 files changed, 11 insertions(+), 1 deletion(-)
@@ -620,7 +620,7 @@ irqreturn_t mtu3_qmu_isr(struct mtu3 *mtu)intmtu3_qmu_init(structmtu3*mtu){-+inti;compiletime_assert(QMU_GPD_SIZE==16,"QMU_GPD size SHOULD be 16B");mtu->qmu_gpd_pool=dma_pool_create("QMU_GPD",mtu->dev,
@@ -629,10 +629,19 @@ int mtu3_qmu_init(struct mtu3 *mtu)if(!mtu->qmu_gpd_pool)return-ENOMEM;+/* Let gadget know we can process request larger than max packet */+for(i=1;i<mtu->num_eps;i++)+mtu->ep_array[i].ep.can_exceed_maxp=1;+return0;}voidmtu3_qmu_exit(structmtu3*mtu){+inti;dma_pool_destroy(mtu->qmu_gpd_pool);++/* Disable large request support */+for(i=1;i<mtu->num_eps;i++)+mtu->ep_array[i].ep.can_exceed_maxp=0;}
From: Macpaul Lin <macpaul.lin@mediatek.com> Date: 2020-06-16 12:35:10
If the hardware (like DMA engine) could support large usb request exceeds
maximum packet size, use larger buffer when performing Rx/Tx could reduce
request numbers and improve performance.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/gadget/function/u_serial.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
@@ -80,6 +80,8 @@#define QUEUE_SIZE 16#define WRITE_BUF_SIZE 8192 /* TX only */#define GS_CONSOLE_BUF_SIZE 8192+/* for hardware can do more than max packet */+#define REQ_BUF_SIZE 4096/* console info */structgs_console{
@@ -247,7 +249,8 @@ static int gs_start_tx(struct gs_port *port)break;req=list_entry(pool->next,structusb_request,list);-len=gs_send_packet(port,req->buf,in->maxpacket);+len=gs_send_packet(port,req->buf,in->can_exceed_maxp?+REQ_BUF_SIZE:in->maxpacket);if(len==0){wake_up_interruptible(&port->drain_wait);break;
From: Alan Stern <stern@rowland.harvard.edu> Date: 2020-06-16 14:02:50
On Tue, Jun 16, 2020 at 08:34:43PM +0800, Macpaul Lin wrote:
Some USB hardware like DMA engine can help to process (split) the data
of each URB request into small packets. For example, the max packet size
of high speed is 512 bytes. These kinds of hardware can help to split
the continue Tx/Rx data requests into packets just at the max packet
size during transmission. Hence upper layer software can reduce some
effort for queueing many requests back and forth for larger data.
Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
hardware is ready to support these operations.
This isn't needed. All UDC drivers must be able to support requests that
are larger than the maxpacket size.
Alan Stern
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From: Macpaul Lin <hidden> Date: 2020-06-17 02:27:38
Alan Stern [off-list ref] 於 2020年6月16日 週二 下午10:05寫道：
On Tue, Jun 16, 2020 at 08:34:43PM +0800, Macpaul Lin wrote:
quoted
Some USB hardware like DMA engine can help to process (split) the data
of each URB request into small packets. For example, the max packet size
of high speed is 512 bytes. These kinds of hardware can help to split
the continue Tx/Rx data requests into packets just at the max packet
size during transmission. Hence upper layer software can reduce some
effort for queueing many requests back and forth for larger data.
Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
hardware is ready to support these operations.
This isn't needed. All UDC drivers must be able to support requests that
are larger than the maxpacket size.
Alan Stern
Thanks for your reply, could we just modify the patch 2 (u_serial.c)
for improving
better performance? I'm not sure why there was a restriction about max packet.
Isn't there any historical reason?
--
Best regards,
Macpaul Lin
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From: Macpaul Lin <macpaul.lin@mediatek.com> Date: 2020-06-17 02:47:03
Nowadays some embedded systems use VCOM to transfer large log and data.
Take LTE MODEM as an example, during the long debugging stage, large
log and data were transfer through VCOM when doing field try or in
operator's lab. Here we suggest slightly increase the transfer buffer
in u_serial.c for performance improving.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/gadget/function/u_serial.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
On Wed, Jun 17, 2020 at 10:46:47AM +0800, Macpaul Lin wrote:
Nowadays some embedded systems use VCOM to transfer large log and data.
Take LTE MODEM as an example, during the long debugging stage, large
log and data were transfer through VCOM when doing field try or in
operator's lab. Here we suggest slightly increase the transfer buffer
in u_serial.c for performance improving.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/gadget/function/u_serial.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
What changed from v1? Always put that below the --- line as the
documentation asks for.
v3?
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From: Macpaul Lin <macpaul.lin@mediatek.com> Date: 2020-06-17 05:34:35
On Wed, 2020-06-17 at 07:14 +0200, Greg Kroah-Hartman wrote:
On Wed, Jun 17, 2020 at 10:46:47AM +0800, Macpaul Lin wrote:
quoted
Nowadays some embedded systems use VCOM to transfer large log and data.
Take LTE MODEM as an example, during the long debugging stage, large
log and data were transfer through VCOM when doing field try or in
operator's lab. Here we suggest slightly increase the transfer buffer
in u_serial.c for performance improving.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/gadget/function/u_serial.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
What changed from v1? Always put that below the --- line as the
documentation asks for.
v3?
Sorry, I just forget to add change log, I'll send v3 later.
Thanks!
BR,
Macpaul Lin
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From: Macpaul Lin <macpaul.lin@mediatek.com> Date: 2020-06-17 05:43:20
Nowadays some embedded systems use VCOM to transfer large log and data.
Take LTE MODEM as an example, during the long debugging stage, large
log and data were transfer through VCOM when doing field try or in
operator's lab. Here we suggest slightly increase the transfer buffer
in u_serial.c for performance improving.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
Changes for v2:
- Drop previous patch for adding flag which indicates hardware capability in
gadget.h and in DMA engine according to Alan's suggestion. Thanks.
- Replace requested buffer size "REQ_BUF_SIZE" instead of checking hardware
capability.
- Refine commit messages.
Changes for v3:
- Code: no change.
Commit: Add missing change log in v2.
drivers/usb/gadget/function/u_serial.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
From: Felipe Balbi <balbi@kernel.org> Date: 2020-06-24 06:47:39
Hi,
Macpaul Lin [off-list ref] writes:
quoted hunk
Some USB hardware like DMA engine can help to process (split) the data
of each URB request into small packets. For example, the max packet size
of high speed is 512 bytes. These kinds of hardware can help to split
the continue Tx/Rx data requests into packets just at the max packet
size during transmission. Hence upper layer software can reduce some
effort for queueing many requests back and forth for larger data.
Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
hardware is ready to support these operations.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/mtu3/mtu3_qmu.c | 11 ++++++++++-
include/linux/usb/gadget.h | 1 +
2 files changed, 11 insertions(+), 1 deletion(-)
@@ -620,7 +620,7 @@ irqreturn_t mtu3_qmu_isr(struct mtu3 *mtu)intmtu3_qmu_init(structmtu3*mtu){-+inti;compiletime_assert(QMU_GPD_SIZE==16,"QMU_GPD size SHOULD be 16B");mtu->qmu_gpd_pool=dma_pool_create("QMU_GPD",mtu->dev,
@@ -629,10 +629,19 @@ int mtu3_qmu_init(struct mtu3 *mtu)if(!mtu->qmu_gpd_pool)return-ENOMEM;+/* Let gadget know we can process request larger than max packet */+for(i=1;i<mtu->num_eps;i++)+mtu->ep_array[i].ep.can_exceed_maxp=1;+return0;}voidmtu3_qmu_exit(structmtu3*mtu){+inti;dma_pool_destroy(mtu->qmu_gpd_pool);++/* Disable large request support */+for(i=1;i<mtu->num_eps;i++)+mtu->ep_array[i].ep.can_exceed_maxp=0;}
From: Felipe Balbi <balbi@kernel.org> Date: 2020-06-24 06:48:56
Hi,
Macpaul Lin [off-list ref] writes:
quoted hunk
If the hardware (like DMA engine) could support large usb request exceeds
maximum packet size, use larger buffer when performing Rx/Tx could reduce
request numbers and improve performance.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
drivers/usb/gadget/function/u_serial.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
@@ -80,6 +80,8 @@#define QUEUE_SIZE 16#define WRITE_BUF_SIZE 8192 /* TX only */#define GS_CONSOLE_BUF_SIZE 8192+/* for hardware can do more than max packet */+#define REQ_BUF_SIZE 4096/* console info */structgs_console{
@@ -247,7 +249,8 @@ static int gs_start_tx(struct gs_port *port)break;req=list_entry(pool->next,structusb_request,list);-len=gs_send_packet(port,req->buf,in->maxpacket);+len=gs_send_packet(port,req->buf,in->can_exceed_maxp?+REQ_BUF_SIZE:in->maxpacket);
just do this unconditionally.
quoted hunk
if (len == 0) {
wake_up_interruptible(&port->drain_wait);
break;
@@ -514,7 +517,9 @@ static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, * be as speedy as we might otherwise be. */ for (i = 0; i < n; i++) {- req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);+ req = gs_alloc_req(ep, ep->can_exceed_maxp ?+ REQ_BUF_SIZE : ep->maxpacket,+ GFP_ATOMIC);
allocating 4kiB in atomic isn't very good. A better idea would be to
preallocate a list of requests and recycle them, rather than allocating
every time you need to do a transfer
--
balbi
From: Felipe Balbi <balbi@kernel.org> Date: 2020-06-24 06:50:37
Hi,
Macpaul Lin [off-list ref] writes:
quoted hunk
Nowadays some embedded systems use VCOM to transfer large log and data.
Take LTE MODEM as an example, during the long debugging stage, large
log and data were transfer through VCOM when doing field try or in
operator's lab. Here we suggest slightly increase the transfer buffer
in u_serial.c for performance improving.
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
---
Changes for v2:
- Drop previous patch for adding flag which indicates hardware capability in
gadget.h and in DMA engine according to Alan's suggestion. Thanks.
- Replace requested buffer size "REQ_BUF_SIZE" instead of checking hardware
capability.
- Refine commit messages.
Changes for v3:
- Code: no change.
Commit: Add missing change log in v2.
drivers/usb/gadget/function/u_serial.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
since this can only be applied for the next merge window, it would be
much better if you work rework how requests are used here and, as I
mentioned in the other subthread, preallocate a list of requests that
get recycled. This would allow us to allocate memory without GFP_ATOMIC.
--
balbi