Date:   Mon, 20 Mar 2023 14:53:23 +0300
From:   Serge Semin <fancer.lancer@gmail.com>
To:     Cai Huoqing <cai.huoqing@linux.dev>
Cc:     Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        Vinod Koul <vkoul@kernel.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
        linux-pci@vger.kernel.org
Subject: Re: [PATCH v7 4/5] dmaengine: dw-edma: Add HDMA DebugFS support
Message-ID: <20230320115323.rqirpbvvfmibqqry@mobilestation>
References: <20230315012840.6986-1-cai.huoqing@linux.dev>
 <20230315012840.6986-5-cai.huoqing@linux.dev>
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On Wed, Mar 15, 2023 at 09:28:35AM +0800, Cai Huoqing wrote:
> From: Cai huoqing <cai.huoqing@linux.dev>
> 
> Add HDMA DebugFS support to show register information
> 
> Signed-off-by: Cai huoqing <cai.huoqing@linux.dev>
> ---
> v6->v7:
>   1.Move the change of register file from patch[4/5] to patch[3/5].
> v6 link:
>   https://lore.kernel.org/lkml/20230310032342.17395-5-cai.huoqing@linux.dev/
> 
>  drivers/dma/dw-edma/Makefile             |   3 +-
>  drivers/dma/dw-edma/dw-hdma-v0-core.c    |   2 +
>  drivers/dma/dw-edma/dw-hdma-v0-debugfs.c | 176 +++++++++++++++++++++++
>  drivers/dma/dw-edma/dw-hdma-v0-debugfs.h |  22 +++
>  4 files changed, 202 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
>  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-debugfs.h
> 
> diff --git a/drivers/dma/dw-edma/Makefile b/drivers/dma/dw-edma/Makefile
> index b1c91ef2c63d..83ab58f87760 100644
> --- a/drivers/dma/dw-edma/Makefile
> +++ b/drivers/dma/dw-edma/Makefile
> @@ -1,7 +1,8 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
>  obj-$(CONFIG_DW_EDMA)		+= dw-edma.o
> -dw-edma-$(CONFIG_DEBUG_FS)	:= dw-edma-v0-debugfs.o
> +dw-edma-$(CONFIG_DEBUG_FS)	:= dw-edma-v0-debugfs.o	\
> +				   dw-hdma-v0-debugfs.o
>  dw-edma-objs			:= dw-edma-core.o	\
>  				   dw-edma-v0-core.o	\
>  				   dw-hdma-v0-core.o $(dw-edma-y)
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> index cf274231cda9..b540c9ad7dfb 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> @@ -11,6 +11,7 @@
>  #include "dw-edma-core.h"
>  #include "dw-hdma-v0-core.h"
>  #include "dw-hdma-v0-regs.h"
> +#include "dw-hdma-v0-debugfs.h"
>  
>  enum dw_hdma_control {
>  	DW_HDMA_V0_CB					= BIT(0),
> @@ -257,6 +258,7 @@ static void dw_hdma_v0_core_ch_config(struct dw_edma_chan *chan)
>  /* HDMA debugfs callbacks */
>  static void dw_hdma_v0_core_debugfs_on(struct dw_edma *dw)
>  {
> +	dw_hdma_v0_debugfs_on(dw);
>  }
>  
>  static const struct dw_edma_core_ops dw_hdma_v0_core = {
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> new file mode 100644
> index 000000000000..f2082b1bf72a
> --- /dev/null
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> @@ -0,0 +1,176 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2023 Cai Huoqing
> + * Synopsys DesignWare HDMA v0 debugfs
> + *
> + * Author: Cai Huoqing <cai.huoqing@linux.dev>
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/bitfield.h>
> +
> +#include "dw-hdma-v0-debugfs.h"
> +#include "dw-hdma-v0-regs.h"
> +#include "dw-edma-core.h"
> +
> +#define REGS_ADDR(dw, name)						       \
> +	({								       \
> +		struct dw_hdma_v0_regs __iomem *__regs = (dw)->chip->reg_base; \
> +									       \
> +		(void __iomem *)&__regs->name;				       \
> +	})
> +
> +#define REGS_CH_ADDR(dw, name, _dir, _ch)				       \
> +	({								       \
> +		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;		       \
> +									       \
> +		if (_dir == EDMA_DIR_READ)				       \
> +			__ch_regs = REGS_ADDR(dw, ch[_ch].rd);		       \
> +		else							       \
> +			__ch_regs = REGS_ADDR(dw, ch[_ch].wr);		       \
> +									       \
> +		(void __iomem *)&__ch_regs->name;			       \
> +	})
> +
> +#define CTX_REGISTER(dw, name, dir, ch) \
> +	{ dw, #name, REGS_CH_ADDR(dw, name, dir, ch), dir, ch }
> +
> +#define REGISTER(dw, name) \
> +	{ dw, #name, REGS_ADDR(dw, name) }
> +
> +#define WRITE_STR				"write"
> +#define READ_STR				"read"
> +#define CHANNEL_STR				"channel"
> +#define REGISTERS_STR				"registers"
> +
> +struct dw_hdma_debugfs_entry {
> +	struct dw_edma				*dw;
> +	const char				*name;
> +	void __iomem				*reg;

> +	enum dw_edma_dir			dir;
> +	u16					ch;

Fields above seems like unused. What about dropping them?
* Note the CTX_REGISTER() initializer will need to be fixed too.

BTW it doesn't seem like HDMA will ever need the fields above, does it?
In case of DW eDMA they were necessary to perform the viewport-based
access of the CSR. AFAICS HDMA has always unrolled CSRs mapping.
Am I right?

Other than that looks good.

-Serge(y)

> +};
> +
> +static int dw_hdma_debugfs_u32_get(void *data, u64 *val)
> +{
> +	struct dw_hdma_debugfs_entry *entry = data;
> +	void __iomem *reg = entry->reg;
> +
> +	*val = readl(reg);
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, dw_hdma_debugfs_u32_get, NULL, "0x%08llx\n");
> +
> +static void dw_hdma_debugfs_create_x32(struct dw_edma *dw,
> +				       const struct dw_hdma_debugfs_entry ini[],
> +				       int nr_entries, struct dentry *dent)
> +{
> +	struct dw_hdma_debugfs_entry *entries;
> +	int i;
> +
> +	entries = devm_kcalloc(dw->chip->dev, nr_entries, sizeof(*entries),
> +			       GFP_KERNEL);
> +	if (!entries)
> +		return;
> +
> +	for (i = 0; i < nr_entries; i++) {
> +		entries[i] = ini[i];
> +
> +		debugfs_create_file_unsafe(entries[i].name, 0444, dent,
> +					   &entries[i], &fops_x32);
> +	}
> +}
> +
> +static void dw_hdma_debugfs_regs_ch(struct dw_edma *dw, enum dw_edma_dir dir,
> +				    u16 ch, struct dentry *dent)
> +{
> +	const struct dw_hdma_debugfs_entry debugfs_regs[] = {
> +		CTX_REGISTER(dw, ch_en, dir, ch),
> +		CTX_REGISTER(dw, doorbell, dir, ch),
> +		CTX_REGISTER(dw, prefetch, dir, ch),
> +		CTX_REGISTER(dw, handshake, dir, ch),
> +		CTX_REGISTER(dw, llp.lsb, dir, ch),
> +		CTX_REGISTER(dw, llp.msb, dir, ch),
> +		CTX_REGISTER(dw, cycle_sync, dir, ch),
> +		CTX_REGISTER(dw, transfer_size, dir, ch),
> +		CTX_REGISTER(dw, sar.lsb, dir, ch),
> +		CTX_REGISTER(dw, sar.msb, dir, ch),
> +		CTX_REGISTER(dw, dar.lsb, dir, ch),
> +		CTX_REGISTER(dw, dar.msb, dir, ch),
> +		CTX_REGISTER(dw, watermark_en, dir, ch),
> +		CTX_REGISTER(dw, control1, dir, ch),
> +		CTX_REGISTER(dw, func_num, dir, ch),
> +		CTX_REGISTER(dw, qos, dir, ch),
> +		CTX_REGISTER(dw, ch_stat, dir, ch),
> +		CTX_REGISTER(dw, int_stat, dir, ch),
> +		CTX_REGISTER(dw, int_setup, dir, ch),
> +		CTX_REGISTER(dw, int_clear, dir, ch),
> +		CTX_REGISTER(dw, msi_stop.lsb, dir, ch),
> +		CTX_REGISTER(dw, msi_stop.msb, dir, ch),
> +		CTX_REGISTER(dw, msi_watermark.lsb, dir, ch),
> +		CTX_REGISTER(dw, msi_watermark.msb, dir, ch),
> +		CTX_REGISTER(dw, msi_abort.lsb, dir, ch),
> +		CTX_REGISTER(dw, msi_abort.msb, dir, ch),
> +		CTX_REGISTER(dw, msi_msgdata, dir, ch),
> +	};
> +	int nr_entries = ARRAY_SIZE(debugfs_regs);
> +
> +	dw_hdma_debugfs_create_x32(dw, debugfs_regs, nr_entries, dent);
> +}
> +
> +static void dw_hdma_debugfs_regs_wr(struct dw_edma *dw, struct dentry *dent)
> +{
> +	struct dentry *regs_dent, *ch_dent;
> +	char name[16];
> +	int i;
> +
> +	regs_dent = debugfs_create_dir(WRITE_STR, dent);
> +
> +	for (i = 0; i < dw->wr_ch_cnt; i++) {
> +		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
> +
> +		ch_dent = debugfs_create_dir(name, regs_dent);
> +
> +		dw_hdma_debugfs_regs_ch(dw, EDMA_DIR_WRITE, i, ch_dent);
> +	}
> +}
> +
> +static void dw_hdma_debugfs_regs_rd(struct dw_edma *dw, struct dentry *dent)
> +{
> +	struct dentry *regs_dent, *ch_dent;
> +	char name[16];
> +	int i;
> +
> +	regs_dent = debugfs_create_dir(READ_STR, dent);
> +
> +	for (i = 0; i < dw->rd_ch_cnt; i++) {
> +		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
> +
> +		ch_dent = debugfs_create_dir(name, regs_dent);
> +
> +		dw_hdma_debugfs_regs_ch(dw, EDMA_DIR_READ, i, ch_dent);
> +	}
> +}
> +
> +static void dw_hdma_debugfs_regs(struct dw_edma *dw)
> +{
> +	struct dentry *regs_dent;
> +
> +	regs_dent = debugfs_create_dir(REGISTERS_STR, dw->dma.dbg_dev_root);
> +
> +	dw_hdma_debugfs_regs_wr(dw, regs_dent);
> +	dw_hdma_debugfs_regs_rd(dw, regs_dent);
> +}
> +
> +void dw_hdma_v0_debugfs_on(struct dw_edma *dw)
> +{
> +	if (!debugfs_initialized())
> +		return;
> +
> +	debugfs_create_u32("mf", 0444, dw->dma.dbg_dev_root, &dw->chip->mf);
> +	debugfs_create_u16("wr_ch_cnt", 0444, dw->dma.dbg_dev_root, &dw->wr_ch_cnt);
> +	debugfs_create_u16("rd_ch_cnt", 0444, dw->dma.dbg_dev_root, &dw->rd_ch_cnt);
> +
> +	dw_hdma_debugfs_regs(dw);
> +}
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.h b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.h
> new file mode 100644
> index 000000000000..e6842c83777d
> --- /dev/null
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.h
> @@ -0,0 +1,22 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2023 Cai Huoqing
> + * Synopsys DesignWare HDMA v0 debugfs
> + *
> + * Author: Cai Huoqing <cai.huoqing@linux.dev>
> + */
> +
> +#ifndef _DW_HDMA_V0_DEBUG_FS_H
> +#define _DW_HDMA_V0_DEBUG_FS_H
> +
> +#include <linux/dma/edma.h>
> +
> +#ifdef CONFIG_DEBUG_FS
> +void dw_hdma_v0_debugfs_on(struct dw_edma *dw);
> +#else
> +static inline void dw_hdma_v0_debugfs_on(struct dw_edma *dw)
> +{
> +}
> +#endif /* CONFIG_DEBUG_FS */
> +
> +#endif /* _DW_HDMA_V0_DEBUG_FS_H */
> -- 
> 2.34.1
>