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[PATCH V2 1/3] MIPS: lantiq: add DMA support

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH V2 1/3] MIPS: lantiq: add DMA support
From: John Crispin <blogic@openwrt.org>
Date: Fri, 6 May 2011 00:10:00 +0200
Cc: John Crispin <blogic@openwrt.org>, Ralph Hempel <ralph.hempel@lantiq.com>, linux-mips@linux-mips.org
In-reply-to: <1304633402-24161-1-git-send-email-blogic@openwrt.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1304633402-24161-1-git-send-email-blogic@openwrt.org>
Sender: linux-mips-bounce@linux-mips.org
This patch adds support for the DMA engine found inside the XWAY family of
SoCs. The engine has 5 ports and 20 channels.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Cc: linux-mips@linux-mips.org

---

Changes in V2
* use spinlocks

 .../mips/include/asm/mach-lantiq/xway/lantiq_soc.h |    3 +-
 arch/mips/include/asm/mach-lantiq/xway/xway_dma.h  |   60 +++++
 arch/mips/lantiq/xway/Makefile                     |    2 +-
 arch/mips/lantiq/xway/dma.c                        |  272 ++++++++++++++++++++
 4 files changed, 335 insertions(+), 2 deletions(-)
 create mode 100644 arch/mips/include/asm/mach-lantiq/xway/xway_dma.h
 create mode 100644 arch/mips/lantiq/xway/dma.c

diff --git a/arch/mips/include/asm/mach-lantiq/xway/lantiq_soc.h 
b/arch/mips/include/asm/mach-lantiq/xway/lantiq_soc.h
index 34bc993..95f1882 100644
--- a/arch/mips/include/asm/mach-lantiq/xway/lantiq_soc.h
+++ b/arch/mips/include/asm/mach-lantiq/xway/lantiq_soc.h
@@ -85,7 +85,8 @@
 #define LTQ_PPE32_SIZE         0x40000
 
 /* DMA */
-#define LTQ_DMA_BASE_ADDR      0xBE104100
+#define LTQ_DMA_BASE_ADDR      0x1E104100
+#define LTQ_DMA_SIZE           0x800
 
 /* PCI */
 #define PCI_CR_BASE_ADDR       0x1E105400
diff --git a/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h 
b/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h
new file mode 100644
index 0000000..872943a
--- /dev/null
+++ b/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h
@@ -0,0 +1,60 @@
+/*
+ *   This program is free software; you can redistribute it and/or modify it
+ *   under the terms of the GNU General Public License version 2 as published
+ *   by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ *
+ *   Copyright (C) 2011 John Crispin <blogic@openwrt.org>
+ */
+
+#ifndef LTQ_DMA_H__
+#define LTQ_DMA_H__
+
+#define LTQ_DESC_SIZE          0x08    /* each descriptor is 64bit */
+#define LTQ_DESC_NUM           0x40    /* 64 descriptors / channel */
+
+#define LTQ_DMA_OWN            BIT(31) /* owner bit */
+#define LTQ_DMA_C              BIT(30) /* complete bit */
+#define LTQ_DMA_SOP            BIT(29) /* start of packet */
+#define LTQ_DMA_EOP            BIT(28) /* end of packet */
+#define LTQ_DMA_TX_OFFSET(x)   ((x & 0x1f) << 23) /* data bytes offset */
+#define LTQ_DMA_RX_OFFSET(x)   ((x & 0x7) << 23) /* data bytes offset */
+#define LTQ_DMA_SIZE_MASK      (0xffff) /* the size field is 16 bit */
+
+struct ltq_dma_desc {
+       u32 ctl;
+       u32 addr;
+};
+
+struct ltq_dma_channel {
+       int nr;                         /* the channel number */
+       int irq;                        /* the mapped irq */
+       int desc;                       /* the current descriptor */
+       struct ltq_dma_desc *desc_base; /* the descriptor base */
+       int phys;                       /* physical addr */
+};
+
+enum {
+       DMA_PORT_ETOP = 0,
+       DMA_PORT_DEU,
+};
+
+extern void ltq_dma_enable_irq(struct ltq_dma_channel *ch);
+extern void ltq_dma_disable_irq(struct ltq_dma_channel *ch);
+extern void ltq_dma_ack_irq(struct ltq_dma_channel *ch);
+extern void ltq_dma_open(struct ltq_dma_channel *ch);
+extern void ltq_dma_close(struct ltq_dma_channel *ch);
+extern void ltq_dma_alloc_tx(struct ltq_dma_channel *ch);
+extern void ltq_dma_alloc_rx(struct ltq_dma_channel *ch);
+extern void ltq_dma_free(struct ltq_dma_channel *ch);
+extern void ltq_dma_init_port(int p);
+
+#endif
diff --git a/arch/mips/lantiq/xway/Makefile b/arch/mips/lantiq/xway/Makefile
index a021def..d88a3e8 100644
--- a/arch/mips/lantiq/xway/Makefile
+++ b/arch/mips/lantiq/xway/Makefile
@@ -1,4 +1,4 @@
-obj-y := pmu.o ebu.o reset.o gpio.o gpio_stp.o gpio_ebu.o devices.o
+obj-y := pmu.o ebu.o reset.o gpio.o gpio_stp.o gpio_ebu.o devices.o dma.o
 
 obj-$(CONFIG_SOC_XWAY) += clk-xway.o prom-xway.o
 obj-$(CONFIG_SOC_AMAZON_SE) += clk-ase.o prom-ase.o
diff --git a/arch/mips/lantiq/xway/dma.c b/arch/mips/lantiq/xway/dma.c
new file mode 100644
index 0000000..485d5bf
--- /dev/null
+++ b/arch/mips/lantiq/xway/dma.c
@@ -0,0 +1,272 @@
+/*
+ *   This program is free software; you can redistribute it and/or modify it
+ *   under the terms of the GNU General Public License version 2 as published
+ *   by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ *
+ *   Copyright (C) 2011 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+
+#include <lantiq_soc.h>
+#include <xway_dma.h>
+
+#define LTQ_DMA_CTRL           0x10
+#define LTQ_DMA_CPOLL          0x14
+#define LTQ_DMA_CS             0x18
+#define LTQ_DMA_CCTRL          0x1C
+#define LTQ_DMA_CDBA           0x20
+#define LTQ_DMA_CDLEN          0x24
+#define LTQ_DMA_CIS            0x28
+#define LTQ_DMA_CIE            0x2C
+#define LTQ_DMA_PS             0x40
+#define LTQ_DMA_PCTRL          0x44
+#define LTQ_DMA_IRNEN          0xf4
+
+#define DMA_DESCPT             BIT(3)          /* descriptor complete irq */
+#define DMA_TX                 BIT(8)          /* TX channel direction */
+#define DMA_CHAN_ON            BIT(0)          /* channel on / off bit */
+#define DMA_PDEN               BIT(6)          /* enable packet drop */
+#define DMA_CHAN_RST           BIT(1)          /* channel on / off bit */
+#define DMA_RESET              BIT(0)          /* channel on / off bit */
+#define DMA_IRQ_ACK            0x7e            /* IRQ status register */
+#define DMA_POLL               BIT(31)         /* turn on channel polling */
+#define DMA_CLK_DIV4           BIT(6)          /* polling clock divider */
+#define DMA_2W_BURST           BIT(1)          /* 2 word burst length */
+#define DMA_MAX_CHANNEL                20              /* the soc has 20 
channels */
+#define DMA_ETOP_ENDIANESS     (0xf << 8) /* endianess swap etop channels */
+#define DMA_WEIGHT     (BIT(17) | BIT(16))     /* default channel wheight */
+
+#define ltq_dma_r32(x)                 ltq_r32(ltq_dma_membase + (x))
+#define ltq_dma_w32(x, y)              ltq_w32(x, ltq_dma_membase + (y))
+#define ltq_dma_w32_mask(x, y, z)      ltq_w32_mask(x, y, \
+                                               ltq_dma_membase + (z))
+
+static void __iomem *ltq_dma_membase;
+
+void
+ltq_dma_enable_irq(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       local_irq_save(flags);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32_mask(0, 1 << ch->nr, LTQ_DMA_IRNEN);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_enable_irq);
+
+void
+ltq_dma_disable_irq(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       local_irq_save(flags);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32_mask(1 << ch->nr, 0, LTQ_DMA_IRNEN);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_disable_irq);
+
+void
+ltq_dma_ack_irq(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       local_irq_save(flags);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32(DMA_IRQ_ACK, LTQ_DMA_CIS);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_ack_irq);
+
+void
+ltq_dma_open(struct ltq_dma_channel *ch)
+{
+       unsigned long flag;
+
+       local_irq_save(flag);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32_mask(0, DMA_CHAN_ON, LTQ_DMA_CCTRL);
+       ltq_dma_enable_irq(ch);
+       local_irq_restore(flag);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_open);
+
+void
+ltq_dma_close(struct ltq_dma_channel *ch)
+{
+       unsigned long flag;
+
+       local_irq_save(flag);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32_mask(DMA_CHAN_ON, 0, LTQ_DMA_CCTRL);
+       ltq_dma_disable_irq(ch);
+       local_irq_restore(flag);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_close);
+
+static void
+ltq_dma_alloc(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       ch->desc = 0;
+       ch->desc_base = dma_alloc_coherent(NULL,
+                               LTQ_DESC_NUM * LTQ_DESC_SIZE,
+                               &ch->phys, GFP_ATOMIC);
+       memset(ch->desc_base, 0, LTQ_DESC_NUM * LTQ_DESC_SIZE);
+
+       local_irq_save(flags);
+       ltq_dma_w32(ch->nr, LTQ_DMA_CS);
+       ltq_dma_w32(ch->phys, LTQ_DMA_CDBA);
+       ltq_dma_w32(LTQ_DESC_NUM, LTQ_DMA_CDLEN);
+       ltq_dma_w32_mask(DMA_CHAN_ON, 0, LTQ_DMA_CCTRL);
+       wmb();
+       ltq_dma_w32_mask(0, DMA_CHAN_RST, LTQ_DMA_CCTRL);
+       while (ltq_dma_r32(LTQ_DMA_CCTRL) & DMA_CHAN_RST)
+               ;
+       local_irq_restore(flags);
+}
+
+void
+ltq_dma_alloc_tx(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       ltq_dma_alloc(ch);
+
+       local_irq_save(flags);
+       ltq_dma_w32(DMA_DESCPT, LTQ_DMA_CIE);
+       ltq_dma_w32_mask(0, 1 << ch->nr, LTQ_DMA_IRNEN);
+       ltq_dma_w32(DMA_WEIGHT | DMA_TX, LTQ_DMA_CCTRL);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_alloc_tx);
+
+void
+ltq_dma_alloc_rx(struct ltq_dma_channel *ch)
+{
+       unsigned long flags;
+
+       ltq_dma_alloc(ch);
+
+       local_irq_save(flags);
+       ltq_dma_w32(DMA_DESCPT, LTQ_DMA_CIE);
+       ltq_dma_w32_mask(0, 1 << ch->nr, LTQ_DMA_IRNEN);
+       ltq_dma_w32(DMA_WEIGHT, LTQ_DMA_CCTRL);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_alloc_rx);
+
+void
+ltq_dma_free(struct ltq_dma_channel *ch)
+{
+       if (!ch->desc_base)
+               return;
+       ltq_dma_close(ch);
+       dma_free_coherent(NULL, LTQ_DESC_NUM * LTQ_DESC_SIZE,
+               ch->desc_base, ch->phys);
+}
+EXPORT_SYMBOL_GPL(ltq_dma_free);
+
+void
+ltq_dma_init_port(int p)
+{
+       ltq_dma_w32(p, LTQ_DMA_PS);
+       switch (p) {
+       case DMA_PORT_ETOP:
+               /*
+                * Tell the DMA engine to swap the endianess of data frames and
+                * drop packets if the channel arbitration fails.
+                */
+               ltq_dma_w32_mask(0, DMA_ETOP_ENDIANESS | DMA_PDEN,
+                       LTQ_DMA_PCTRL);
+               break;
+
+       case DMA_PORT_DEU:
+               ltq_dma_w32((DMA_2W_BURST << 4) | (DMA_2W_BURST << 2),
+                       LTQ_DMA_PCTRL);
+               break;
+
+       default:
+               break;
+       }
+}
+EXPORT_SYMBOL_GPL(ltq_dma_init_port);
+
+static int
+ltq_dma_probe(struct platform_device *pdev)
+{
+       struct resource *res;
+       int i;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               dev_err(&pdev->dev, "failed to get dma resource\n");
+               return -ENOENT;
+       }
+
+       res = devm_request_mem_region(&pdev->dev, res->start,
+               resource_size(res), dev_name(&pdev->dev));
+       if (!res) {
+               dev_err(&pdev->dev, "failed to request dma resource\n");
+               return -EBUSY;
+       }
+
+       ltq_dma_membase = devm_ioremap_nocache(&pdev->dev,
+               res->start, resource_size(res));
+       if (!ltq_dma_membase) {
+               dev_err(&pdev->dev, "failed to remap dma engine %d\n",
+                       pdev->id);
+               return -ENOMEM;
+       }
+
+       /* power up and reset the dma engine */
+       ltq_pmu_enable(PMU_DMA);
+       ltq_dma_w32_mask(0, DMA_RESET, LTQ_DMA_CTRL);
+
+       /* disable all interrupts */
+       ltq_dma_w32(0, LTQ_DMA_IRNEN);
+
+       /* reset/configure each channel */
+       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+               ltq_dma_w32(i, LTQ_DMA_CS);
+               ltq_dma_w32(DMA_CHAN_RST, LTQ_DMA_CCTRL);
+               ltq_dma_w32(DMA_POLL | DMA_CLK_DIV4, LTQ_DMA_CPOLL);
+               ltq_dma_w32_mask(DMA_CHAN_ON, 0, LTQ_DMA_CCTRL);
+       }
+       return 0;
+}
+
+static struct platform_driver ltq_dma_driver = {
+       .probe = ltq_dma_probe,
+       .driver = {
+               .name = "ltq_dma",
+               .owner = THIS_MODULE,
+       },
+};
+
+int __init
+ltq_dma_init(void)
+{
+       int ret = platform_driver_register(&ltq_dma_driver);
+
+       if (ret)
+               pr_info("ltq_dma : Error registering platfom driver!");
+       return ret;
+}
+
+postcore_initcall(ltq_dma_init);
-- 
1.7.2.3


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