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7b0c03ecc4
This patch adds a new device-tree property that allows to
specify the dma protection control bits for the all of the
DMA controller's channel uniformly.
Setting the "correct" bits can have a huge impact on the
PPC460EX and APM82181 that use this DMA engine in combination
with a DesignWare' SATA-II core (sata_dwc_460ex driver).
In the OpenWrt Forum, the user takimata reported that:
|It seems your patch unleashed the full power of the SATA port.
|Where I was previously hitting a really hard limit at around
|82 MB/s for reading and 27 MB/s for writing, I am now getting this:
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|root@OpenWrt:/mnt# time dd if=/dev/zero of=tempfile bs=1M count=1024
|1024+0 records in
|1024+0 records out
|real 0m 13.65s
|user 0m 0.01s
|sys 0m 11.89s
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|root@OpenWrt:/mnt# time dd if=tempfile of=/dev/null bs=1M count=1024
|1024+0 records in
|1024+0 records out
|real 0m 8.41s
|user 0m 0.01s
|sys 0m 4.70s
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|This means: 121 MB/s reading and 75 MB/s writing!
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|The drive is a WD Green WD10EARX taken from an older MBL Single.
|I repeated the test a few times with even larger files to rule out
|any caching, I'm still seeing the same great performance. OpenWrt is
|now completely on par with the original MBL firmware's performance.
Another user And.short reported:
|I can report that your fix worked! Boots up fine with two
|drives even with more partitions, and no more reboot on
|concurrent disk access!
A closer look into the sata_dwc_460ex code revealed that
the driver did initally set the correct protection control
bits. However, this feature was lost when the sata_dwc_460ex
driver was converted to the generic DMA driver framework.
BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/55
BugLink: https://forum.openwrt.org/t/wd-mybook-live-duo-two-disks/16195/50
Fixes: 8b3444852a ("sata_dwc_460ex: move to generic DMA driver")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
77 lines
2.6 KiB
C
77 lines
2.6 KiB
C
/*
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* Driver for the Synopsys DesignWare DMA Controller
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*
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* Copyright (C) 2007 Atmel Corporation
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* Copyright (C) 2010-2011 ST Microelectronics
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef _PLATFORM_DATA_DMA_DW_H
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#define _PLATFORM_DATA_DMA_DW_H
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#include <linux/device.h>
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#define DW_DMA_MAX_NR_MASTERS 4
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#define DW_DMA_MAX_NR_CHANNELS 8
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/**
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* struct dw_dma_slave - Controller-specific information about a slave
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*
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* @dma_dev: required DMA master device
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* @src_id: src request line
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* @dst_id: dst request line
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* @m_master: memory master for transfers on allocated channel
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* @p_master: peripheral master for transfers on allocated channel
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* @hs_polarity:set active low polarity of handshake interface
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*/
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struct dw_dma_slave {
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struct device *dma_dev;
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u8 src_id;
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u8 dst_id;
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u8 m_master;
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u8 p_master;
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bool hs_polarity;
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};
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/**
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* struct dw_dma_platform_data - Controller configuration parameters
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* @nr_channels: Number of channels supported by hardware (max 8)
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* @is_private: The device channels should be marked as private and not for
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* by the general purpose DMA channel allocator.
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* @is_memcpy: The device channels do support memory-to-memory transfers.
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* @is_idma32: The type of the DMA controller is iDMA32
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* @chan_allocation_order: Allocate channels starting from 0 or 7
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* @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0.
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* @block_size: Maximum block size supported by the controller
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* @nr_masters: Number of AHB masters supported by the controller
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* @data_width: Maximum data width supported by hardware per AHB master
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* (in bytes, power of 2)
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* @multi_block: Multi block transfers supported by hardware per channel.
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* @protctl: Protection control signals setting per channel.
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*/
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struct dw_dma_platform_data {
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unsigned int nr_channels;
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bool is_private;
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bool is_memcpy;
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bool is_idma32;
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#define CHAN_ALLOCATION_ASCENDING 0 /* zero to seven */
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#define CHAN_ALLOCATION_DESCENDING 1 /* seven to zero */
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unsigned char chan_allocation_order;
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#define CHAN_PRIORITY_ASCENDING 0 /* chan0 highest */
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#define CHAN_PRIORITY_DESCENDING 1 /* chan7 highest */
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unsigned char chan_priority;
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unsigned int block_size;
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unsigned char nr_masters;
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unsigned char data_width[DW_DMA_MAX_NR_MASTERS];
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unsigned char multi_block[DW_DMA_MAX_NR_CHANNELS];
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#define CHAN_PROTCTL_PRIVILEGED BIT(0)
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#define CHAN_PROTCTL_BUFFERABLE BIT(1)
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#define CHAN_PROTCTL_CACHEABLE BIT(2)
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#define CHAN_PROTCTL_MASK GENMASK(2, 0)
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unsigned char protctl;
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};
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#endif /* _PLATFORM_DATA_DMA_DW_H */
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