dmaengine: Add Synopsys eDMA IP version 0 debugfs support

Add Synopsys eDMA IP version 0 debugfs support to assist any debug
in the future.

Creates a file system structure composed by folders and files that mimic
the IP register map (this files are read only) to ease any debug.

To enable this feature is necessary to select DEBUG_FS option on kernel
configuration.

Small output example:

(eDMA IP version 0, unroll, 1 write + 1 read channels)

% mount -t debugfs none /sys/kernel/debug/
% tree /sys/kernel/debug/dw-edma-core:0/
dw-edma/
├── version
├── mode
├── wr_ch_cnt
├── rd_ch_cnt
└── registers
    ├── ctrl_data_arb_prior
    ├── ctrl
    ├── write
    │   ├── engine_en
    │   ├── doorbell
    │   ├── ch_arb_weight_low
    │   ├── ch_arb_weight_high
    │   ├── int_status
    │   ├── int_mask
    │   ├── int_clear
    │   ├── err_status
    │   ├── done_imwr_low
    │   ├── done_imwr_high
    │   ├── abort_imwr_low
    │   ├── abort_imwr_high
    │   ├── ch01_imwr_data
    │   ├── ch23_imwr_data
    │   ├── ch45_imwr_data
    │   ├── ch67_imwr_data
    │   ├── linked_list_err_en
    │   ├── engine_chgroup
    │   ├── engine_hshake_cnt_low
    │   ├── engine_hshake_cnt_high
    │   ├── ch0_pwr_en
    │   ├── ch1_pwr_en
    │   ├── ch2_pwr_en
    │   ├── ch3_pwr_en
    │   ├── ch4_pwr_en
    │   ├── ch5_pwr_en
    │   ├── ch6_pwr_en
    │   ├── ch7_pwr_en
    │   └── channel:0
    │       ├── ch_control1
    │       ├── ch_control2
    │       ├── transfer_size
    │       ├── sar_low
    │       ├── sar_high
    │       ├── dar_high
    │       ├── llp_low
    │       └── llp_high
    └── read
        ├── engine_en
        ├── doorbell
        ├── ch_arb_weight_low
        ├── ch_arb_weight_high
        ├── int_status
        ├── int_mask
        ├── int_clear
        ├── err_status_low
        ├── err_status_high
        ├── done_imwr_low
        ├── done_imwr_high
        ├── abort_imwr_low
        ├── abort_imwr_high
        ├── ch01_imwr_data
        ├── ch23_imwr_data
        ├── ch45_imwr_data
        ├── ch67_imwr_data
        ├── linked_list_err_en
        ├── engine_chgroup
        ├── engine_hshake_cnt_low
        ├── engine_hshake_cnt_high
        ├── ch0_pwr_en
        ├── ch1_pwr_en
        ├── ch2_pwr_en
        ├── ch3_pwr_en
        ├── ch4_pwr_en
        ├── ch5_pwr_en
        ├── ch6_pwr_en
        ├── ch7_pwr_en
        └── channel:0
            ├── ch_control1
            ├── ch_control2
            ├── transfer_size
            ├── sar_low
            ├── sar_high
            ├── dar_high
            ├── llp_low
            └── llp_high

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.h b/drivers/dma/dw-edma/dw-edma-v0-debugfs.h
new file mode 100644
index 000000000000..5450a0a94193
--- /dev/null
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018-2019 Synopsys, Inc. and/or its affiliates.
+ * Synopsys DesignWare eDMA v0 core
+ *
+ * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
+ */
+
+#ifndef _DW_EDMA_V0_DEBUG_FS_H
+#define _DW_EDMA_V0_DEBUG_FS_H
+
+#include <linux/dma/edma.h>
+
+#ifdef CONFIG_DEBUG_FS
+void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip);
+void dw_edma_v0_debugfs_off(void);
+#else
+static inline void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip)
+{
+}
+
+static inline void dw_edma_v0_debugfs_off(void)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+#endif /* _DW_EDMA_V0_DEBUG_FS_H */