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Message-ID: <486deaa3-d139-d4af-e0cf-e324b3270f3b@gmail.com>
Date: Fri, 23 Aug 2019 15:50:54 +0200
From: Matthias Brugger <matthias.bgg@...il.com>
To: Bibby Hsieh <bibby.hsieh@...iatek.com>,
Jassi Brar <jassisinghbrar@...il.com>,
Rob Herring <robh+dt@...nel.org>, CK HU <ck.hu@...iatek.com>
Cc: Daniel Kurtz <djkurtz@...omium.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
Sascha Hauer <kernel@...gutronix.de>,
Philipp Zabel <p.zabel@...gutronix.de>,
Nicolas Boichat <drinkcat@...omium.org>,
YT Shen <yt.shen@...iatek.com>,
Daoyuan Huang <daoyuan.huang@...iatek.com>,
Jiaguang Zhang <jiaguang.zhang@...iatek.com>,
Dennis-YC Hsieh <dennis-yc.hsieh@...iatek.com>,
Houlong Wei <houlong.wei@...iatek.com>, ginny.chen@...iatek.com
Subject: Re: [RESEND, PATCH v13 09/12] soc: mediatek: cmdq: define the
instruction struct
On 20/08/2019 10:49, Bibby Hsieh wrote:
> Define an instruction structure for gce driver to append command.
> This structure can make the client's code more readability.
>
> Signed-off-by: Bibby Hsieh <bibby.hsieh@...iatek.com>
> Reviewed-by: CK Hu <ck.hu@...iatek.com>
> ---
> drivers/soc/mediatek/mtk-cmdq-helper.c | 106 +++++++++++++++--------
> include/linux/mailbox/mtk-cmdq-mailbox.h | 2 +
> 2 files changed, 74 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
> index 7aa0517ff2f3..e3d5b0be8e79 100644
> --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> @@ -9,12 +9,24 @@
> #include <linux/mailbox_controller.h>
> #include <linux/soc/mediatek/mtk-cmdq.h>
>
> -#define CMDQ_ARG_A_WRITE_MASK 0xffff
> #define CMDQ_WRITE_ENABLE_MASK BIT(0)
> #define CMDQ_EOC_IRQ_EN BIT(0)
> #define CMDQ_EOC_CMD ((u64)((CMDQ_CODE_EOC << CMDQ_OP_CODE_SHIFT)) \
> << 32 | CMDQ_EOC_IRQ_EN)
>
> +struct cmdq_instruction {
> + union {
> + u32 value;
> + u32 mask;
> + };
> + union {
> + u16 offset;
> + u16 event;
> + };
> + u8 subsys;
> + u8 op;
> +};
> +
> static void cmdq_client_timeout(struct timer_list *t)
> {
> struct cmdq_client *client = from_timer(client, t, timer);
> @@ -110,10 +122,8 @@ void cmdq_pkt_destroy(struct cmdq_pkt *pkt)
> }
> EXPORT_SYMBOL(cmdq_pkt_destroy);
>
> -static int cmdq_pkt_append_command(struct cmdq_pkt *pkt, enum cmdq_code code,
> - u32 arg_a, u32 arg_b)
> +static struct cmdq_instruction *cmdq_pkt_append_command(struct cmdq_pkt *pkt)
> {
> - u64 *cmd_ptr;
>
> if (unlikely(pkt->cmd_buf_size + CMDQ_INST_SIZE > pkt->buf_size)) {
> /*
> @@ -127,81 +137,109 @@ static int cmdq_pkt_append_command(struct cmdq_pkt *pkt, enum cmdq_code code,
> pkt->cmd_buf_size += CMDQ_INST_SIZE;
> WARN_ONCE(1, "%s: buffer size %u is too small !\n",
> __func__, (u32)pkt->buf_size);
> - return -ENOMEM;
> + return NULL;
> }
> - cmd_ptr = pkt->va_base + pkt->cmd_buf_size;
> - (*cmd_ptr) = (u64)((code << CMDQ_OP_CODE_SHIFT) | arg_a) << 32 | arg_b;
> +
> + *(u64 *)(pkt->va_base + pkt->cmd_buf_size) = 0;> pkt->cmd_buf_size += CMDQ_INST_SIZE;
>
> - return 0;
> + return pkt->va_base + pkt->cmd_buf_size - CMDQ_INST_SIZE;
> }
>
> int cmdq_pkt_write(struct cmdq_pkt *pkt, u8 subsys, u16 offset, u32 value)
> {
> - u32 arg_a = (offset & CMDQ_ARG_A_WRITE_MASK) |
> - (subsys << CMDQ_SUBSYS_SHIFT);
> + struct cmdq_instruction *inst;
> +
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
> +
> + inst->op = CMDQ_CODE_WRITE;
> + inst->value = value;
> + inst->offset = offset;
> + inst->subsys = subsys;
>
I can see that using cmdq_instruction will make the code more readable, but I
dislike the approach that cmdq_pkt_append_command returns a pointer where we
write the instruction to. Better we pass inst to cmdq_pkt_append_command() and
write it there to cmd_ptr.
I think this way we can get rid of explicitly setting the memory to zero:
*(u64 *)(pkt->va_base + pkt->cmd_buf_size) = 0;
And if we pass the inst to the append_command we don't have to change the return
value handling of cmdq_pkt_append_command(), which makes the patch easier to
understand.
> - return cmdq_pkt_append_command(pkt, CMDQ_CODE_WRITE, arg_a, value);
> + return 0;
> }
> EXPORT_SYMBOL(cmdq_pkt_write);
>
> int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u8 subsys,
> u16 offset, u32 value, u32 mask)
> {
> - u32 offset_mask = offset;
> - int err = 0;
> + struct cmdq_instruction *inst;
> + u16 offset_mask = offset;
>
> if (mask != 0xffffffff) {
> - err = cmdq_pkt_append_command(pkt, CMDQ_CODE_MASK, 0, ~mask);
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
> +
> + inst->op = CMDQ_CODE_MASK;
> + inst->mask = ~mask;
> offset_mask |= CMDQ_WRITE_ENABLE_MASK;
> }
> - err |= cmdq_pkt_write(pkt, value, subsys, offset_mask);
>
> - return err;
> + return cmdq_pkt_write(pkt, subsys, offset_mask, value);
> }
> EXPORT_SYMBOL(cmdq_pkt_write_mask);
>
> int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event)
> {
> - u32 arg_b;
> + struct cmdq_instruction *inst;
>
> if (event >= CMDQ_MAX_EVENT)
> return -EINVAL;
>
> - /*
> - * WFE arg_b
> - * bit 0-11: wait value
> - * bit 15: 1 - wait, 0 - no wait
> - * bit 16-27: update value
> - * bit 31: 1 - update, 0 - no update
> - */
I have no strong opinion of CMDQ_WFE_OPTION but if you want to introduce it,
then please copy the comment over to include/linux/mailbox/mtk-cmdq-mailbox.h
Just one question, why did you call it _OPTION? It's not really expressive for me.
> - arg_b = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
> +
> + inst->op = CMDQ_CODE_WFE;
> + inst->value = CMDQ_WFE_OPTION;
> + inst->event = event;
>
> - return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE, event, arg_b);
> + return 0;
> }
> EXPORT_SYMBOL(cmdq_pkt_wfe);
>
> int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, u16 event)
> {
> + struct cmdq_instruction *inst;
> +
> if (event >= CMDQ_MAX_EVENT)
> return -EINVAL;
>
> - return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE, event,
> - CMDQ_WFE_UPDATE);
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
> +
> + inst->op = CMDQ_CODE_WFE;
> + inst->value = CMDQ_WFE_UPDATE;
> + inst->event = event;
> +
> + return 0;
> }
> EXPORT_SYMBOL(cmdq_pkt_clear_event);
>
> static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> {
> - int err;
> + struct cmdq_instruction *inst;
> +
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
>
> - /* insert EOC and generate IRQ for each command iteration */
Please don't delete the comment.
> - err = cmdq_pkt_append_command(pkt, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
> + inst->op = CMDQ_CODE_EOC;
> + inst->value = CMDQ_EOC_IRQ_EN;
>
> - /* JUMP to end */
Same here.
Regards,
Matthias
> - err |= cmdq_pkt_append_command(pkt, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
> + inst = cmdq_pkt_append_command(pkt);
> + if (!inst)
> + return -ENOMEM;
> +
> + inst->op = CMDQ_CODE_JUMP;
> + inst->value = CMDQ_JUMP_PASS;
>
> - return err;
> + return 0;
> }
>
> static void cmdq_pkt_flush_async_cb(struct cmdq_cb_data data)
> diff --git a/include/linux/mailbox/mtk-cmdq-mailbox.h b/include/linux/mailbox/mtk-cmdq-mailbox.h
> index 911475da7a53..c8adedefaf42 100644
> --- a/include/linux/mailbox/mtk-cmdq-mailbox.h
> +++ b/include/linux/mailbox/mtk-cmdq-mailbox.h
> @@ -19,6 +19,8 @@
> #define CMDQ_WFE_UPDATE BIT(31)
> #define CMDQ_WFE_WAIT BIT(15)
> #define CMDQ_WFE_WAIT_VALUE 0x1
> +#define CMDQ_WFE_OPTION (CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | \
> + CMDQ_WFE_WAIT_VALUE)
> /** cmdq event maximum */
> #define CMDQ_MAX_EVENT 0x3ff
>
>
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