From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Vinod Koul <vkoul@kernel.org>, Viresh Kumar <vireshk@kernel.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>
Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru>,
Serge Semin <fancer.lancer@gmail.com>,
Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Arnd Bergmann <arnd@arndb.de>, Rob Herring <robh+dt@kernel.org>,
<linux-mips@vger.kernel.org>, <devicetree@vger.kernel.org>,
<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v6 8/9] dmaengine: dw: Initialize min and max burst DMA device capability
Date: Thu, 18 Jun 2020 02:40:27 +0300 [thread overview]
Message-ID: <20200617234028.25808-9-Sergey.Semin@baikalelectronics.ru> (raw)
In-Reply-To: <20200617234028.25808-1-Sergey.Semin@baikalelectronics.ru>
According to the DW APB DMAC data book the minimum burst transaction
length is 1 and it's true for any version of the controller since
isn't parametrised in the coreAssembler so can't be changed at the
IP-core synthesis stage. The maximum burst transaction can vary from
channel to channel and from controller to controller depending on a
IP-core parameter the system engineer activated during the IP-core
synthesis. Let's initialise both min_burst and max_burst members of the
DMA controller descriptor with extreme values so the DMA clients could
use them to properly optimize the DMA requests. The channels and
controller-specific max_burst length initialization will be introduced
by the follow-up patches.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
---
Changelog v4:
- This is a new patch suggested by Andy.
Changelog v5:
- Introduce macro with extreme min and max burst length supported by the
DW DMA controller.
- Initialize max_burst length capability with extreme burst length supported
by the DW DMAC IP-core.
---
drivers/dma/dw/core.c | 2 ++
include/linux/platform_data/dma-dw.h | 2 ++
2 files changed, 4 insertions(+)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index ceded21537e2..4887aa2fc73c 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1229,6 +1229,8 @@ int do_dma_probe(struct dw_dma_chip *chip)
dw->dma.device_issue_pending = dwc_issue_pending;
/* DMA capabilities */
+ dw->dma.min_burst = DW_DMA_MIN_BURST;
+ dw->dma.max_burst = DW_DMA_MAX_BURST;
dw->dma.src_addr_widths = DW_DMA_BUSWIDTHS;
dw->dma.dst_addr_widths = DW_DMA_BUSWIDTHS;
dw->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index f3eaf9ec00a1..369e41e9dcc9 100644
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -12,6 +12,8 @@
#define DW_DMA_MAX_NR_MASTERS 4
#define DW_DMA_MAX_NR_CHANNELS 8
+#define DW_DMA_MIN_BURST 1
+#define DW_DMA_MAX_BURST 256
/**
* struct dw_dma_slave - Controller-specific information about a slave
--
2.26.2
next prev parent reply other threads:[~2020-06-17 23:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-17 23:40 [PATCH RESEND v6 0/9] dmaengine: dw: Take Baikal-T1 SoC DW DMAC peculiarities into account Serge Semin
2020-06-17 23:40 ` [PATCH v6 1/9] dt-bindings: dma: dw: Convert DW DMAC to DT binding Serge Semin
2020-06-18 8:21 ` Andy Shevchenko
2020-06-19 17:01 ` Serge Semin
2020-06-17 23:40 ` [PATCH v6 2/9] dt-bindings: dma: dw: Add max burst transaction length property Serge Semin
2020-06-17 23:40 ` [PATCH v6 3/9] dmaengine: Introduce min burst length capability Serge Semin
2020-06-17 23:40 ` [PATCH v6 4/9] dmaengine: Introduce DMA-device device_caps callback Serge Semin
2020-06-17 23:40 ` [PATCH v6 5/9] dmaengine: dw: Take HC_LLP flag into account for noLLP auto-config Serge Semin
2020-06-17 23:40 ` [PATCH v6 6/9] dmaengine: dw: Set DMA device max segment size parameter Serge Semin
2020-06-17 23:40 ` [PATCH v6 7/9] dmaengine: dw: Add dummy device_caps callback Serge Semin
2020-06-17 23:40 ` Serge Semin [this message]
2020-06-17 23:40 ` [PATCH v6 9/9] dmaengine: dw: Introduce max burst length hw config Serge Semin
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