dmaengine: dw-edma: increase size of 'name' in debugfs code

We seem to have hit warnings of 'output may be truncated' which is fixed
by increasing the size of 'name'

drivers/dma/dw-edma/dw-hdma-v0-debugfs.c: In function ‘dw_hdma_v0_debugfs_on’:
drivers/dma/dw-edma/dw-hdma-v0-debugfs.c:125:50: error: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 8 [-Werror=format-truncation=]
125 | snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
| ^~

drivers/dma/dw-edma/dw-hdma-v0-debugfs.c: In function ‘dw_hdma_v0_debugfs_on’:
drivers/dma/dw-edma/dw-hdma-v0-debugfs.c:142:50: error: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 8 [-Werror=format-truncation=]
142 | snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
| ^~
drivers/dma/dw-edma/dw-edma-v0-debugfs.c: In function ‘dw_edma_debugfs_regs_wr’:
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:193:50: error: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 8 [-Werror=format-truncation=]
193 | snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
| ^~

Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Use DMA engine device debugfs subdirectory

Since all DW eDMA read and write channels are now installed in a framework
of a single DMA engine device, move all the DW eDMA-specific debugfs nodes
into a ready-to-use DMA-engine debugfs subdirectory. It's created during
the DMA-device registration and can be found in the dma_device.dbg_dev_root
field.

Link: https://lore.kernel.org/r/20230113171409.30470-19-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Move eDMA data pointer to debugfs node descriptor

The last thing that stops the debugfs part of the eDMA driver from
supporting multi-eDMA platforms is keeping the eDMA private data pointer in
the static area of the debugfs module. Since the debugfs node descriptors
are now heap-allocated, we can freely move that pointer to being preserved
in the descriptors. After the debugfs initialization procedure, that
pointer will be used in the debugfs files getter to access the common CSRs
space and the context CSRs spinlock. So the main part of this change is
connected with the debugfs nodes descriptors initialization macros, which
aside with already defined prototypes now require to have the DW eDMA
private data pointer passed.

[bhelgaas: squash in https://lore.kernel.org/r/20230130185101.2883245-1-arnd@kernel.org]
Link: https://lore.kernel.org/r/20230113171409.30470-17-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Simplify debugfs context CSRs init procedure

DW eDMA v4.70a and older have the read and write channels context CSRs
indirectly accessible, which means CSRs like Channel Control, Xfer size,
SAR, DAR and LLP address are accessed at a fixed MMIO address, with their
reference to the corresponding channel determined by the Viewport CSR. To
have a coherent access to these registers the CSR IOs are supposed to be
protected with a spinlock. DW eDMA v4.80a and newer normally have unrolled
Read/Write channel context registers, with these CSRs directly mapped in
the controller MMIO space.

Both normal and viewport-based registers are exposed via debugfs nodes, and
the original algorithm was based on the unrolled CSRs mapping and
recalculated the viewport addresses when required. This is unscalable (it
only supports a platform with a single eDMA since a base address is
statically preserved) and also needlessly overcomplicated (it loops over
all Rd/Wr context addresses and recalculates the viewport base address on
each debugfs node access).

Simplify the algorithm by adding the channel ID and its direction fields in
the eDMA debugfs node descriptor. These new fields can be used to find a
CSR offset in the channel register space. The DW eDMA debugfs node getter
will also use them to activate the respective context CSRs viewport before
reading data from the specified register. For the unrolled CSR mapping, no
spinlock or viewport activation is needed.

Note: this replaces some REGISTER() uses with CTX_REGISTER(), which avoids
an implicit dependency on a local variable name. The same problem with the
rest of the macro will be fixed in the next commit.

Link: https://lore.kernel.org/r/20230113171409.30470-16-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Rename debugfs dentry variables to 'dent'

Since we are about to add the eDMA channels direction support to the
debugfs module it will be confusing to have both the debugfs directory and
the channels direction short names used in the same code.

Rename the debugfs dentry 'dir' variables to 'dent' to prevent confusion.

Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20230113171409.30470-15-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Convert debugfs descs to being heap-allocated

Currently DW eDMA debugfs node descriptors are allocated on the stack,
which won't work for multi-eDMA platforms. As a preparation to supporting
multi-eDMA systems, allocate each debugfs node separately. Afterwards
we'll add info like Read/Write channel flag, channel ID, DW eDMA private
data reference.

Note: this conversion is mainly required due to having the legacy DW eDMA
controllers with indirect Read/Write channels context CSRs access. If we
didn't need to synchronize access to these registers, the debugfs code of
the driver would have been much simpler.

Link: https://lore.kernel.org/r/20230113171409.30470-14-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Add dw_edma prefix to debugfs nodes descriptor

Other local names include a "dw_edma" prefix.

Add a "dw_edma" prefix to the debugfs_entries structure, too, so it won't
be confused with global debugfs things.

Link: https://lore.kernel.org/r/20230113171409.30470-13-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Stop checking debugfs_create_*() return value

The debugfs_create_*() functions never return NULL, so checking their
return value for NULL is pointless. Secondly, the debugfs subsystem is
designed to be as simple as possible, so if one of the debugfs_create_*()
method in a hierarchy fails, the following methods should silently return
the passed erroneous parental dentry. Finally, the code should work no
matter whether anything debugfs-related fails.

To make code simpler and debugfs-independent, stop checking the
debugfs_create_*() return values.

If the debugfs file system is unavailable, skip the debugfs node
initialization altogether to preserve some memory space.

Link: https://lore.kernel.org/r/20230113171409.30470-12-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Drop unnecessary debugfs reg casts

The debugfs_entries structure declared in dw-edma-v0-debugfs.c contains the
debugfs node register address. The address is declared as dma_addr_t type,
but is cast to "void *".

Change the type to "void __iomem *" and drop the unnecessary casts.

Link: https://lore.kernel.org/r/20230113171409.30470-11-Sergey.Semin@baikalelectronics.ru
Fixes: 305aebeff879 ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Change rg_region to reg_base in struct dw_edma_chip

struct dw_edma_region rg_region included virtual address, physical address
and size information. But only the virtual address is used by EDMA driver.
Change it to void __iomem *reg_base to clean up code.

Link: https://lore.kernel.org/r/20220524152159.2370739-4-Frank.Li@nxp.com
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Detach the private data and chip info structures

"struct dw_edma_chip" contains an internal structure "struct dw_edma" that
is used by the eDMA core internally and should not be touched by the eDMA
controller drivers themselves. But currently, the eDMA controller drivers
like "dw-edma-pci" allocate and populate this internal structure before
passing it on to the eDMA core. The eDMA core further populates the
structure and uses it. This is wrong!

Hence, move all the "struct dw_edma" specifics from controller drivers to
the eDMA core.

Link: https://lore.kernel.org/r/20220524152159.2370739-3-Frank.Li@nxp.com
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Move struct dentry variable from static definition into dw_edma struct

Move struct dentry variable from static definition (dw-edma-v0-debugfs.c)
into dw_edma struct (dw-edma-core.h)

Also the variable was renamed from base_dir to debugfs.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/07c1167b671e7b175700e2e7061cf0b3dd8c6adb.1613674948.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Add support for the HDMA feature

Add support for the HDMA feature.

This new feature enables the current eDMA IP to use a deeper prefetch
of the linked list, which reduces the algorithm execution latency
observed when loading the elements of the list, causing more stable
and higher data transfer.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/5f40f89ef7d6255a12d5b23f34e6e59dcd28861e.1613674948.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Add writeq() and readq() for 64 bits architectures

Add writeq() and readq() for 64 bits architures support.

Supporting these two functions will allow the write or the read of eDMA
64 bits registers at once instead of having two consecutive operations.

Also, this improvement will allow the PCI optimization transaction
messages, which will generate a 64 bits message instead of two messages
of 32 bits.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/3f1120f7c6003b38ec8b851fc68936007c4d9fd8.1613674948.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: Fix Using plain integer as NULL pointer in dw-edma-v0-debugfs.c

Fixes warning given by executing "make C=2 drivers/dma/dw-edma/"

Sparse output:
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:296:49: warning:
Using plain integer as NULL pointer

Cc: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/6569fd8ca5ddaa73afef1241ad7978c2a1fae0c7.1600206938.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: fix __iomem type confusion

The new driver mixes up dma_addr_t and __iomem pointers, which results
in warnings on some 32-bit architectures, like:

drivers/dma/dw-edma/dw-edma-v0-core.c: In function '__dw_regs':
drivers/dma/dw-edma/dw-edma-v0-core.c:28:9: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
return (struct dw_edma_v0_regs __iomem *)dw->rg_region.vaddr;

Make it use __iomem pointers consistently here, and avoid using dma_addr_t
for __iomem tokens altogether.

A small complication here is the debugfs code, which passes an __iomem
token as the private data for debugfs files, requiring the use of
extra __force.

Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Link: https://lore.kernel.org/lkml/20190617131918.2518727-1-arnd@arndb.de/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190722124457.1093886-2-arnd@arndb.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: dw-edma: fix unnecessary stack usage

Putting large constant data on the stack causes unnecessary overhead
and stack usage:

drivers/dma/dw-edma/dw-edma-v0-debugfs.c:285:6: error: stack frame size of 1376 bytes in function 'dw_edma_v0_debugfs_on' [-Werror,-Wframe-larger-than=]

Mark the variable 'static const' in order for the compiler to move it
into the .rodata section where it does no such harm.

Fixes: 305aebeff879 ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/20190722124457.1093886-1-arnd@arndb.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

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>