[RESEND v6 0/1] firmware: mtk: add adsp ipc protocol for sof
This patch provides mtk adsp ipc support for sof.
ADSP IPC protocol offers (send/recv) interfaces using mediatek-mailbox APIs.
This was tested and confirmed on MT8195 cherry board with sof.
Based on linux-next
changes since v5: - fix WARNING: modpost: missing MODULE_LICENSE() in drivers/mailbox /mtk-adsp-mailbox.o. Add MODULE_LICENSE in the last line. - Due to WARNING: Missing or malformed SPDX-License-Identifier tag in line 1 in checkpatch, we don't remove SPDX-License in line 1.
changes since v4: - add error message for wrong mbox chan
changes since v3: - rebase on v5.16-rc8 - update reviewers
changes since v2: - add out tag for two memory free phases
changes since v1: - add comments for mtk_adsp_ipc_send and mtk_adsp_ipc_recv - remove useless MODULE_LICENSE - change label name to out_free
Allen-KH Cheng (1): firmware: mediatek: add adsp ipc protocol interface
drivers/firmware/Kconfig | 1 + drivers/firmware/Makefile | 1 + drivers/firmware/mediatek/Kconfig | 9 + drivers/firmware/mediatek/Makefile | 2 + drivers/firmware/mediatek/mtk-adsp-ipc.c | 161 ++++++++++++++++++ .../linux/firmware/mediatek/mtk-adsp-ipc.h | 65 +++++++ 6 files changed, 239 insertions(+) create mode 100644 drivers/firmware/mediatek/Kconfig create mode 100644 drivers/firmware/mediatek/Makefile create mode 100644 drivers/firmware/mediatek/mtk-adsp-ipc.c create mode 100644 include/linux/firmware/mediatek/mtk-adsp-ipc.h
From: Allen-KH Cheng Allen-KH.Cheng@mediatek.com
Some of mediatek processors contain the Tensilica HiFix DSP for audio processing.
The communication between Host CPU and DSP firmware is taking place using a shared memory area for message passing.
ADSP IPC protocol offers (send/recv) interfaces using mediatek-mailbox APIs.
We use two mbox channels to implement a request-reply protocol.
Signed-off-by: Allen-KH Cheng allen-kh.cheng@mediatek.com Reviewed-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Reviewed-by: Curtis Malainey cujomalainey@chromium.org Reviewed-by: Tzung-Bi Shih tzungbi@google.com Reviewed-by: YC Hung yc.hung@mediatek.com Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com --- drivers/firmware/Kconfig | 1 + drivers/firmware/Makefile | 1 + drivers/firmware/mediatek/Kconfig | 9 + drivers/firmware/mediatek/Makefile | 2 + drivers/firmware/mediatek/mtk-adsp-ipc.c | 161 ++++++++++++++++++ .../linux/firmware/mediatek/mtk-adsp-ipc.h | 65 +++++++ 6 files changed, 239 insertions(+) create mode 100644 drivers/firmware/mediatek/Kconfig create mode 100644 drivers/firmware/mediatek/Makefile create mode 100644 drivers/firmware/mediatek/mtk-adsp-ipc.c create mode 100644 include/linux/firmware/mediatek/mtk-adsp-ipc.h
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 75cb91055c17..f3578c60cff0 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -299,6 +299,7 @@ source "drivers/firmware/cirrus/Kconfig" source "drivers/firmware/google/Kconfig" source "drivers/firmware/efi/Kconfig" source "drivers/firmware/imx/Kconfig" +source "drivers/firmware/mediatek/Kconfig" source "drivers/firmware/meson/Kconfig" source "drivers/firmware/psci/Kconfig" source "drivers/firmware/smccc/Kconfig" diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index 4e58cb474a68..88fbdc110100 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_GOOGLE_FIRMWARE) += google/ obj-$(CONFIG_EFI) += efi/ obj-$(CONFIG_UEFI_CPER) += efi/ obj-y += imx/ +obj-y += mediatek/ obj-y += psci/ obj-y += smccc/ obj-y += tegra/ diff --git a/drivers/firmware/mediatek/Kconfig b/drivers/firmware/mediatek/Kconfig new file mode 100644 index 000000000000..6d1e580b967b --- /dev/null +++ b/drivers/firmware/mediatek/Kconfig @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +config MTK_ADSP_IPC + tristate "MTK ADSP IPC Protocol driver" + depends on MTK_ADSP_MBOX + help + Say yes here to add support for the MediaTek ADSP IPC + between host AP (Linux) and the firmware running on ADSP. + ADSP exists on some mtk processors. + Client might use shared memory to exchange information with ADSP side. diff --git a/drivers/firmware/mediatek/Makefile b/drivers/firmware/mediatek/Makefile new file mode 100644 index 000000000000..4e840b65650d --- /dev/null +++ b/drivers/firmware/mediatek/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_MTK_ADSP_IPC) += mtk-adsp-ipc.o diff --git a/drivers/firmware/mediatek/mtk-adsp-ipc.c b/drivers/firmware/mediatek/mtk-adsp-ipc.c new file mode 100644 index 000000000000..9c535d2688d9 --- /dev/null +++ b/drivers/firmware/mediatek/mtk-adsp-ipc.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2022 MediaTek Corporation. All rights reserved. + * Author: Allen-KH Cheng allen-kh.cheng@mediatek.com + */ + +#include <linux/firmware/mediatek/mtk-adsp-ipc.h> +#include <linux/kernel.h> +#include <linux/mailbox_client.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +/* + * mtk_adsp_ipc_send - send ipc cmd to MTK ADSP + * + * @ipc: ADSP IPC handle + * @idx: index of the mailbox channel + * @msg: IPC cmd (reply or request) + * + * Returns zero for success from mbox_send_message + * negative value for error + */ +int mtk_adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t msg) +{ + struct mtk_adsp_chan *adsp_chan; + int ret; + + if (idx >= MTK_ADSP_MBOX_NUM) + return -EINVAL; + + adsp_chan = &ipc->chans[idx]; + ret = mbox_send_message(adsp_chan->ch, &msg); + if (ret < 0) + return ret; + + /* + * mbox_send_message returns non-negative value on success, + * return zero for success + */ + return 0; +} +EXPORT_SYMBOL(mtk_adsp_ipc_send); + +/* + * mtk_adsp_ipc_recv - recv callback used by MTK ADSP mailbox + * + * @c: mbox client + * @msg: message received + * + * Users of ADSP IPC will need to privde handle_reply and handle_request + * callbacks. + */ +static void mtk_adsp_ipc_recv(struct mbox_client *c, void *msg) +{ + struct mtk_adsp_chan *chan = container_of(c, struct mtk_adsp_chan, cl); + struct device *dev = c->dev; + + switch (chan->idx) { + case MTK_ADSP_MBOX_REPLY: + chan->ipc->ops->handle_reply(chan->ipc); + break; + case MTK_ADSP_MBOX_REQUEST: + chan->ipc->ops->handle_request(chan->ipc); + break; + default: + dev_err(dev, "wrong mbox chan %d\n", chan->idx); + break; + } +} + +static int mtk_adsp_ipc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct mtk_adsp_ipc *adsp_ipc; + struct mtk_adsp_chan *adsp_chan; + struct mbox_client *cl; + char *chan_name; + int ret; + int i, j; + + device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent); + + adsp_ipc = devm_kzalloc(dev, sizeof(*adsp_ipc), GFP_KERNEL); + if (!adsp_ipc) + return -ENOMEM; + + for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) { + chan_name = kasprintf(GFP_KERNEL, "mbox%d", i); + if (!chan_name) { + ret = -ENOMEM; + goto out; + } + + adsp_chan = &adsp_ipc->chans[i]; + cl = &adsp_chan->cl; + cl->dev = dev->parent; + cl->tx_block = false; + cl->knows_txdone = false; + cl->tx_prepare = NULL; + cl->rx_callback = mtk_adsp_ipc_recv; + + adsp_chan->ipc = adsp_ipc; + adsp_chan->idx = i; + adsp_chan->ch = mbox_request_channel_byname(cl, chan_name); + if (IS_ERR(adsp_chan->ch)) { + ret = PTR_ERR(adsp_chan->ch); + if (ret != -EPROBE_DEFER) + dev_err(dev, "Failed to request mbox chan %d ret %d\n", + i, ret); + goto out_free; + } + + dev_dbg(dev, "request mbox chan %s\n", chan_name); + kfree(chan_name); + } + + adsp_ipc->dev = dev; + dev_set_drvdata(dev, adsp_ipc); + dev_dbg(dev, "MTK ADSP IPC initialized\n"); + + return 0; + +out_free: + kfree(chan_name); +out: + for (j = 0; j < i; j++) { + adsp_chan = &adsp_ipc->chans[j]; + mbox_free_channel(adsp_chan->ch); + } + + return ret; +} + +static int mtk_adsp_ipc_remove(struct platform_device *pdev) +{ + struct mtk_adsp_ipc *adsp_ipc = dev_get_drvdata(&pdev->dev); + struct mtk_adsp_chan *adsp_chan; + int i; + + for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) { + adsp_chan = &adsp_ipc->chans[i]; + mbox_free_channel(adsp_chan->ch); + } + + return 0; +} + +static struct platform_driver mtk_adsp_ipc_driver = { + .driver = { + .name = "mtk-adsp-ipc", + }, + .probe = mtk_adsp_ipc_probe, + .remove = mtk_adsp_ipc_remove, +}; +builtin_platform_driver(mtk_adsp_ipc_driver); + +MODULE_AUTHOR("Allen-KH Cheng allen-kh.cheng@mediatek.com"); +MODULE_DESCRIPTION("MTK ADSP IPC Driver"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/firmware/mediatek/mtk-adsp-ipc.h b/include/linux/firmware/mediatek/mtk-adsp-ipc.h new file mode 100644 index 000000000000..28fd313340b8 --- /dev/null +++ b/include/linux/firmware/mediatek/mtk-adsp-ipc.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2022 MediaTek Inc. + */ + +#ifndef MTK_ADSP_IPC_H +#define MTK_ADSP_IPC_H + +#include <linux/device.h> +#include <linux/types.h> +#include <linux/mailbox_controller.h> +#include <linux/mailbox_client.h> + +#define MTK_ADSP_IPC_REQ 0 +#define MTK_ADSP_IPC_RSP 1 +#define MTK_ADSP_IPC_OP_REQ 0x1 +#define MTK_ADSP_IPC_OP_RSP 0x2 + +enum { + MTK_ADSP_MBOX_REPLY, + MTK_ADSP_MBOX_REQUEST, + MTK_ADSP_MBOX_NUM, +}; + +struct mtk_adsp_ipc; + +struct mtk_adsp_ipc_ops { + void (*handle_reply)(struct mtk_adsp_ipc *ipc); + void (*handle_request)(struct mtk_adsp_ipc *ipc); +}; + +struct mtk_adsp_chan { + struct mtk_adsp_ipc *ipc; + struct mbox_client cl; + struct mbox_chan *ch; + char *name; + int idx; +}; + +struct mtk_adsp_ipc { + struct mtk_adsp_chan chans[MTK_ADSP_MBOX_NUM]; + struct device *dev; + struct mtk_adsp_ipc_ops *ops; + void *private_data; +}; + +static inline void mtk_adsp_ipc_set_data(struct mtk_adsp_ipc *ipc, void *data) +{ + if (!ipc) + return; + + ipc->private_data = data; +} + +static inline void *mtk_adsp_ipc_get_data(struct mtk_adsp_ipc *ipc) +{ + if (!ipc) + return NULL; + + return ipc->private_data; +} + +int mtk_adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t op); + +#endif /* MTK_ADSP_IPC_H */
Hi Matthias,
Could you please help me confirm this patch?
I'd appreciate your help
Best regards, Allen
On Thu, 2022-02-24 at 21:37 +0800, Allen-KH Cheng wrote:
From: Allen-KH Cheng Allen-KH.Cheng@mediatek.com
Some of mediatek processors contain the Tensilica HiFix DSP for audio processing.
The communication between Host CPU and DSP firmware is taking place using a shared memory area for message passing.
ADSP IPC protocol offers (send/recv) interfaces using mediatek-mailbox APIs.
We use two mbox channels to implement a request-reply protocol.
Signed-off-by: Allen-KH Cheng allen-kh.cheng@mediatek.com Reviewed-by: Pierre-Louis Bossart < pierre-louis.bossart@linux.intel.com> Reviewed-by: Curtis Malainey cujomalainey@chromium.org Reviewed-by: Tzung-Bi Shih tzungbi@google.com Reviewed-by: YC Hung yc.hung@mediatek.com Reviewed-by: AngeloGioacchino Del Regno < angelogioacchino.delregno@collabora.com>
drivers/firmware/Kconfig | 1 + drivers/firmware/Makefile | 1 + drivers/firmware/mediatek/Kconfig | 9 + drivers/firmware/mediatek/Makefile | 2 + drivers/firmware/mediatek/mtk-adsp-ipc.c | 161 ++++++++++++++++++ .../linux/firmware/mediatek/mtk-adsp-ipc.h | 65 +++++++ 6 files changed, 239 insertions(+) create mode 100644 drivers/firmware/mediatek/Kconfig create mode 100644 drivers/firmware/mediatek/Makefile create mode 100644 drivers/firmware/mediatek/mtk-adsp-ipc.c create mode 100644 include/linux/firmware/mediatek/mtk-adsp-ipc.h
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 75cb91055c17..f3578c60cff0 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -299,6 +299,7 @@ source "drivers/firmware/cirrus/Kconfig" source "drivers/firmware/google/Kconfig" source "drivers/firmware/efi/Kconfig" source "drivers/firmware/imx/Kconfig" +source "drivers/firmware/mediatek/Kconfig" source "drivers/firmware/meson/Kconfig" source "drivers/firmware/psci/Kconfig" source "drivers/firmware/smccc/Kconfig" diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index 4e58cb474a68..88fbdc110100 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_GOOGLE_FIRMWARE) += google/ obj-$(CONFIG_EFI) += efi/ obj-$(CONFIG_UEFI_CPER) += efi/ obj-y += imx/ +obj-y += mediatek/ obj-y += psci/ obj-y += smccc/ obj-y += tegra/ diff --git a/drivers/firmware/mediatek/Kconfig b/drivers/firmware/mediatek/Kconfig new file mode 100644 index 000000000000..6d1e580b967b --- /dev/null +++ b/drivers/firmware/mediatek/Kconfig @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +config MTK_ADSP_IPC
- tristate "MTK ADSP IPC Protocol driver"
- depends on MTK_ADSP_MBOX
- help
Say yes here to add support for the MediaTek ADSP IPCbetween host AP (Linux) and the firmware running on ADSP.ADSP exists on some mtk processors.Client might use shared memory to exchange information withADSP side. diff --git a/drivers/firmware/mediatek/Makefile b/drivers/firmware/mediatek/Makefile new file mode 100644 index 000000000000..4e840b65650d --- /dev/null +++ b/drivers/firmware/mediatek/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_MTK_ADSP_IPC) += mtk-adsp-ipc.o diff --git a/drivers/firmware/mediatek/mtk-adsp-ipc.c b/drivers/firmware/mediatek/mtk-adsp-ipc.c new file mode 100644 index 000000000000..9c535d2688d9 --- /dev/null +++ b/drivers/firmware/mediatek/mtk-adsp-ipc.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (c) 2022 MediaTek Corporation. All rights reserved.
- Author: Allen-KH Cheng allen-kh.cheng@mediatek.com
- */
+#include <linux/firmware/mediatek/mtk-adsp-ipc.h> +#include <linux/kernel.h> +#include <linux/mailbox_client.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/slab.h>
+/*
- mtk_adsp_ipc_send - send ipc cmd to MTK ADSP
- @ipc: ADSP IPC handle
- @idx: index of the mailbox channel
- @msg: IPC cmd (reply or request)
- Returns zero for success from mbox_send_message
- negative value for error
- */
+int mtk_adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t msg) +{
- struct mtk_adsp_chan *adsp_chan;
- int ret;
- if (idx >= MTK_ADSP_MBOX_NUM)
return -EINVAL;- adsp_chan = &ipc->chans[idx];
- ret = mbox_send_message(adsp_chan->ch, &msg);
- if (ret < 0)
return ret;- /*
* mbox_send_message returns non-negative value on success,* return zero for success*/- return 0;
+} +EXPORT_SYMBOL(mtk_adsp_ipc_send);
+/*
- mtk_adsp_ipc_recv - recv callback used by MTK ADSP mailbox
- @c: mbox client
- @msg: message received
- Users of ADSP IPC will need to privde handle_reply and
handle_request
- callbacks.
- */
+static void mtk_adsp_ipc_recv(struct mbox_client *c, void *msg) +{
- struct mtk_adsp_chan *chan = container_of(c, struct
mtk_adsp_chan, cl);
- struct device *dev = c->dev;
- switch (chan->idx) {
- case MTK_ADSP_MBOX_REPLY:
chan->ipc->ops->handle_reply(chan->ipc);break;- case MTK_ADSP_MBOX_REQUEST:
chan->ipc->ops->handle_request(chan->ipc);break;- default:
dev_err(dev, "wrong mbox chan %d\n", chan->idx);break;- }
+}
+static int mtk_adsp_ipc_probe(struct platform_device *pdev) +{
- struct device *dev = &pdev->dev;
- struct mtk_adsp_ipc *adsp_ipc;
- struct mtk_adsp_chan *adsp_chan;
- struct mbox_client *cl;
- char *chan_name;
- int ret;
- int i, j;
- device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
- adsp_ipc = devm_kzalloc(dev, sizeof(*adsp_ipc), GFP_KERNEL);
- if (!adsp_ipc)
return -ENOMEM;- for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) {
chan_name = kasprintf(GFP_KERNEL, "mbox%d", i);if (!chan_name) {ret = -ENOMEM;goto out;}adsp_chan = &adsp_ipc->chans[i];cl = &adsp_chan->cl;cl->dev = dev->parent;cl->tx_block = false;cl->knows_txdone = false;cl->tx_prepare = NULL;cl->rx_callback = mtk_adsp_ipc_recv;adsp_chan->ipc = adsp_ipc;adsp_chan->idx = i;adsp_chan->ch = mbox_request_channel_byname(cl,chan_name);
if (IS_ERR(adsp_chan->ch)) {ret = PTR_ERR(adsp_chan->ch);if (ret != -EPROBE_DEFER)dev_err(dev, "Failed to request mboxchan %d ret %d\n",
i, ret);goto out_free;}dev_dbg(dev, "request mbox chan %s\n", chan_name);kfree(chan_name);- }
- adsp_ipc->dev = dev;
- dev_set_drvdata(dev, adsp_ipc);
- dev_dbg(dev, "MTK ADSP IPC initialized\n");
- return 0;
+out_free:
- kfree(chan_name);
+out:
- for (j = 0; j < i; j++) {
adsp_chan = &adsp_ipc->chans[j];mbox_free_channel(adsp_chan->ch);- }
- return ret;
+}
+static int mtk_adsp_ipc_remove(struct platform_device *pdev) +{
- struct mtk_adsp_ipc *adsp_ipc = dev_get_drvdata(&pdev->dev);
- struct mtk_adsp_chan *adsp_chan;
- int i;
- for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) {
adsp_chan = &adsp_ipc->chans[i];mbox_free_channel(adsp_chan->ch);- }
- return 0;
+}
+static struct platform_driver mtk_adsp_ipc_driver = {
- .driver = {
.name = "mtk-adsp-ipc",- },
- .probe = mtk_adsp_ipc_probe,
- .remove = mtk_adsp_ipc_remove,
+}; +builtin_platform_driver(mtk_adsp_ipc_driver);
+MODULE_AUTHOR("Allen-KH Cheng allen-kh.cheng@mediatek.com"); +MODULE_DESCRIPTION("MTK ADSP IPC Driver"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/firmware/mediatek/mtk-adsp-ipc.h b/include/linux/firmware/mediatek/mtk-adsp-ipc.h new file mode 100644 index 000000000000..28fd313340b8 --- /dev/null +++ b/include/linux/firmware/mediatek/mtk-adsp-ipc.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*
- Copyright (c) 2022 MediaTek Inc.
- */
+#ifndef MTK_ADSP_IPC_H +#define MTK_ADSP_IPC_H
+#include <linux/device.h> +#include <linux/types.h> +#include <linux/mailbox_controller.h> +#include <linux/mailbox_client.h>
+#define MTK_ADSP_IPC_REQ 0 +#define MTK_ADSP_IPC_RSP 1 +#define MTK_ADSP_IPC_OP_REQ 0x1 +#define MTK_ADSP_IPC_OP_RSP 0x2
+enum {
- MTK_ADSP_MBOX_REPLY,
- MTK_ADSP_MBOX_REQUEST,
- MTK_ADSP_MBOX_NUM,
+};
+struct mtk_adsp_ipc;
+struct mtk_adsp_ipc_ops {
- void (*handle_reply)(struct mtk_adsp_ipc *ipc);
- void (*handle_request)(struct mtk_adsp_ipc *ipc);
+};
+struct mtk_adsp_chan {
- struct mtk_adsp_ipc *ipc;
- struct mbox_client cl;
- struct mbox_chan *ch;
- char *name;
- int idx;
+};
+struct mtk_adsp_ipc {
- struct mtk_adsp_chan chans[MTK_ADSP_MBOX_NUM];
- struct device *dev;
- struct mtk_adsp_ipc_ops *ops;
- void *private_data;
+};
+static inline void mtk_adsp_ipc_set_data(struct mtk_adsp_ipc *ipc, void *data) +{
- if (!ipc)
return;- ipc->private_data = data;
+}
+static inline void *mtk_adsp_ipc_get_data(struct mtk_adsp_ipc *ipc) +{
- if (!ipc)
return NULL;- return ipc->private_data;
+}
+int mtk_adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t op);
+#endif /* MTK_ADSP_IPC_H */
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Allen-KH Cheng -
allen-kh.cheng