From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Scjt9-0006ZL-6V for barebox@lists.infradead.org; Thu, 07 Jun 2012 21:05:06 +0000 From: Sascha Hauer Date: Thu, 7 Jun 2012 23:04:56 +0200 Message-Id: <1339103098-32102-3-git-send-email-s.hauer@pengutronix.de> In-Reply-To: <1339103098-32102-1-git-send-email-s.hauer@pengutronix.de> References: <1339103098-32102-1-git-send-email-s.hauer@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 2/4] dma: add mxs-apbh-dma driver To: barebox@lists.infradead.org Cc: Marek Vasut , wsa@pengutronix.de, Wolfram Sang From: Wolfram Sang Based on the U-Boot version. Changed to kernel style register layout, added MX23 support, made MMU aware and adapted to barebox. Signed-off-by: Marek Vasut Signed-off-by: Wolfram Sang Signed-off-by: Sascha Hauer --- arch/arm/mach-mxs/include/mach/dma.h | 145 +++++++++ drivers/Kconfig | 1 + drivers/Makefile | 1 + drivers/dma/Kconfig | 8 + drivers/dma/Makefile | 1 + drivers/dma/apbh_dma.c | 598 ++++++++++++++++++++++++++++++++++ 6 files changed, 754 insertions(+) create mode 100644 arch/arm/mach-mxs/include/mach/dma.h create mode 100644 drivers/dma/Kconfig create mode 100644 drivers/dma/Makefile create mode 100644 drivers/dma/apbh_dma.c diff --git a/arch/arm/mach-mxs/include/mach/dma.h b/arch/arm/mach-mxs/include/mach/dma.h new file mode 100644 index 0000000..52747e2 --- /dev/null +++ b/arch/arm/mach-mxs/include/mach/dma.h @@ -0,0 +1,145 @@ +/* + * Freescale i.MX28 APBH DMA + * + * Copyright (C) 2011 Marek Vasut + * on behalf of DENX Software Engineering GmbH + * + * Based on code from LTIB: + * Copyright 2008-2010 Freescale Semiconductor, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * 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 + * + */ + +#ifndef __DMA_H__ +#define __DMA_H__ + +#include + +#ifndef CONFIG_ARCH_DMA_PIO_WORDS +#define DMA_PIO_WORDS 15 +#else +#define DMA_PIO_WORDS CONFIG_ARCH_DMA_PIO_WORDS +#endif + +#define MXS_DMA_ALIGNMENT 32 + +/* + * MXS DMA channels + */ +enum { + MXS_DMA_CHANNEL_AHB_APBH_SSP0 = 0, + MXS_DMA_CHANNEL_AHB_APBH_SSP1, + MXS_DMA_CHANNEL_AHB_APBH_SSP2, + MXS_DMA_CHANNEL_AHB_APBH_SSP3, + MXS_DMA_CHANNEL_AHB_APBH_GPMI0, + MXS_DMA_CHANNEL_AHB_APBH_GPMI1, + MXS_DMA_CHANNEL_AHB_APBH_GPMI2, + MXS_DMA_CHANNEL_AHB_APBH_GPMI3, + MXS_DMA_CHANNEL_AHB_APBH_GPMI4, + MXS_DMA_CHANNEL_AHB_APBH_GPMI5, + MXS_DMA_CHANNEL_AHB_APBH_GPMI6, + MXS_DMA_CHANNEL_AHB_APBH_GPMI7, + MXS_DMA_CHANNEL_AHB_APBH_SSP, + MXS_MAX_DMA_CHANNELS, +}; + +/* + * MXS DMA hardware command. + * + * This structure describes the in-memory layout of an entire DMA command, + * including space for the maximum number of PIO accesses. See the appropriate + * reference manual for a detailed description of what these fields mean to the + * DMA hardware. + */ +#define MXS_DMA_DESC_COMMAND_MASK 0x3 +#define MXS_DMA_DESC_COMMAND_OFFSET 0 +#define MXS_DMA_DESC_COMMAND_NO_DMAXFER 0x0 +#define MXS_DMA_DESC_COMMAND_DMA_WRITE 0x1 +#define MXS_DMA_DESC_COMMAND_DMA_READ 0x2 +#define MXS_DMA_DESC_COMMAND_DMA_SENSE 0x3 +#define MXS_DMA_DESC_CHAIN (1 << 2) +#define MXS_DMA_DESC_IRQ (1 << 3) +#define MXS_DMA_DESC_NAND_LOCK (1 << 4) +#define MXS_DMA_DESC_NAND_WAIT_4_READY (1 << 5) +#define MXS_DMA_DESC_DEC_SEM (1 << 6) +#define MXS_DMA_DESC_WAIT4END (1 << 7) +#define MXS_DMA_DESC_HALT_ON_TERMINATE (1 << 8) +#define MXS_DMA_DESC_TERMINATE_FLUSH (1 << 9) +#define MXS_DMA_DESC_PIO_WORDS_MASK (0xf << 12) +#define MXS_DMA_DESC_PIO_WORDS_OFFSET 12 +#define MXS_DMA_DESC_BYTES_MASK (0xffff << 16) +#define MXS_DMA_DESC_BYTES_OFFSET 16 + +struct mxs_dma_cmd { + unsigned long next; + unsigned long data; + union { + dma_addr_t address; + unsigned long alternate; + }; + unsigned long pio_words[DMA_PIO_WORDS]; +}; + +/* + * MXS DMA command descriptor. + * + * This structure incorporates an MXS DMA hardware command structure, along + * with metadata. + */ +#define MXS_DMA_DESC_FIRST (1 << 0) +#define MXS_DMA_DESC_LAST (1 << 1) +#define MXS_DMA_DESC_READY (1 << 31) + +struct mxs_dma_desc { + struct mxs_dma_cmd cmd; + unsigned int flags; + dma_addr_t address; + void *buffer; + struct list_head node; +}; + +/** + * MXS DMA channel + * + * This structure represents a single DMA channel. The MXS platform code + * maintains an array of these structures to represent every DMA channel in the + * system (see mxs_dma_channels). + */ +#define MXS_DMA_FLAGS_IDLE 0 +#define MXS_DMA_FLAGS_BUSY (1 << 0) +#define MXS_DMA_FLAGS_FREE 0 +#define MXS_DMA_FLAGS_ALLOCATED (1 << 16) +#define MXS_DMA_FLAGS_VALID (1 << 31) + +struct mxs_dma_chan { + const char *name; + unsigned long dev; + struct mxs_dma_device *dma; + unsigned int flags; + unsigned int active_num; + unsigned int pending_num; + struct list_head active; + struct list_head done; +}; + +struct mxs_dma_desc *mxs_dma_desc_alloc(void); +void mxs_dma_desc_free(struct mxs_dma_desc *); +int mxs_dma_desc_append(int channel, struct mxs_dma_desc *pdesc); + +int mxs_dma_go(int chan); +int mxs_dma_init(void); + +#endif /* __DMA_H__ */ diff --git a/drivers/Kconfig b/drivers/Kconfig index c52c56a..037b0d4 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -17,5 +17,6 @@ source "drivers/eeprom/Kconfig" source "drivers/input/Kconfig" source "drivers/pwm/Kconfig" +source "drivers/dma/Kconfig" endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 3aefc12..f40b321 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -15,3 +15,4 @@ obj-$(CONFIG_LED) += led/ obj-y += eeprom/ obj-$(CONFIG_PWM) += pwm/ obj-y += input/ +obj-y += dma/ diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig new file mode 100644 index 0000000..ec6c894 --- /dev/null +++ b/drivers/dma/Kconfig @@ -0,0 +1,8 @@ +menu "DMA support" + +config MXS_APBH_DMA + tristate "MXS APBH DMA ENGINE" + depends on ARCH_IMX23 || ARCH_IMX28 + help + Experimental! +endmenu diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile new file mode 100644 index 0000000..7a3a3b2 --- /dev/null +++ b/drivers/dma/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_MXS_APBH_DMA) += apbh_dma.o diff --git a/drivers/dma/apbh_dma.c b/drivers/dma/apbh_dma.c new file mode 100644 index 0000000..363878f --- /dev/null +++ b/drivers/dma/apbh_dma.c @@ -0,0 +1,598 @@ +/* + * Freescale i.MX28 APBH DMA driver + * + * Copyright (C) 2011 Wolfram Sang + * + * Copyright (C) 2011 Marek Vasut + * on behalf of DENX Software Engineering GmbH + * + * Based on code from LTIB: + * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define HW_APBHX_CTRL0 0x000 +#define BM_APBH_CTRL0_APB_BURST8_EN (1 << 29) +#define BM_APBH_CTRL0_APB_BURST_EN (1 << 28) +#define BP_APBH_CTRL0_CLKGATE_CHANNEL 8 +#define BP_APBH_CTRL0_RESET_CHANNEL 16 +#define HW_APBHX_CTRL1 0x010 +#define BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN 16 +#define HW_APBHX_CTRL2 0x020 +#define HW_APBHX_CHANNEL_CTRL 0x030 +#define BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL 16 +#define HW_APBH_VERSION (cpu_is_mx23() ? 0x3f0 : 0x800) +#define HW_APBX_VERSION 0x800 +#define BP_APBHX_VERSION_MAJOR 24 +#define HW_APBHX_CHn_NXTCMDAR(n) \ + ((apbh_is_old ? 0x050 : 0x110) + (n) * 0x70) +#define HW_APBHX_CHn_SEMA(n) \ + ((apbh_is_old ? 0x080 : 0x140) + (n) * 0x70) +#define BM_APBHX_CHn_SEMA_PHORE (0xff << 16) +#define BP_APBHX_CHn_SEMA_PHORE 16 + +static struct mxs_dma_chan mxs_dma_channels[MXS_MAX_DMA_CHANNELS]; +static bool apbh_is_old; + +/* + * Test is the DMA channel is valid channel + */ +int mxs_dma_validate_chan(int channel) +{ + struct mxs_dma_chan *pchan; + + if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS)) + return -EINVAL; + + pchan = mxs_dma_channels + channel; + if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED)) + return -EINVAL; + + return 0; +} + +/* + * Return the address of the command within a descriptor. + */ +static unsigned int mxs_dma_cmd_address(struct mxs_dma_desc *desc) +{ + return desc->address + offsetof(struct mxs_dma_desc, cmd); +} + +/* + * Read a DMA channel's hardware semaphore. + * + * As used by the MXS platform's DMA software, the DMA channel's hardware + * semaphore reflects the number of DMA commands the hardware will process, but + * has not yet finished. This is a volatile value read directly from hardware, + * so it must be be viewed as immediately stale. + * + * If the channel is not marked busy, or has finished processing all its + * commands, this value should be zero. + * + * See mxs_dma_append() for details on how DMA command blocks must be configured + * to maintain the expected behavior of the semaphore's value. + */ +static int mxs_dma_read_semaphore(int channel) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + uint32_t tmp; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + tmp = readl(apbh_regs + HW_APBHX_CHn_SEMA(channel)); + + tmp &= BM_APBHX_CHn_SEMA_PHORE; + tmp >>= BP_APBHX_CHn_SEMA_PHORE; + + return tmp; +} + +/* + * Enable a DMA channel. + * + * If the given channel has any DMA descriptors on its active list, this + * function causes the DMA hardware to begin processing them. + * + * This function marks the DMA channel as "busy," whether or not there are any + * descriptors to process. + */ +static int mxs_dma_enable(int channel) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + unsigned int sem; + struct mxs_dma_chan *pchan; + struct mxs_dma_desc *pdesc; + int channel_bit, ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + pchan = mxs_dma_channels + channel; + + if (pchan->pending_num == 0) { + pchan->flags |= MXS_DMA_FLAGS_BUSY; + return 0; + } + + pdesc = list_first_entry(&pchan->active, struct mxs_dma_desc, node); + if (pdesc == NULL) + return -EFAULT; + + if (pchan->flags & MXS_DMA_FLAGS_BUSY) { + if (!(pdesc->cmd.data & MXS_DMA_DESC_CHAIN)) + return 0; + + sem = mxs_dma_read_semaphore(channel); + if (sem == 0) + return 0; + + if (sem == 1) { + pdesc = list_entry(pdesc->node.next, + struct mxs_dma_desc, node); + writel(mxs_dma_cmd_address(pdesc), + apbh_regs + HW_APBHX_CHn_NXTCMDAR(channel)); + } + writel(pchan->pending_num, + apbh_regs + HW_APBHX_CHn_SEMA(channel)); + pchan->active_num += pchan->pending_num; + pchan->pending_num = 0; + } else { + pchan->active_num += pchan->pending_num; + pchan->pending_num = 0; + writel(mxs_dma_cmd_address(pdesc), + apbh_regs + HW_APBHX_CHn_NXTCMDAR(channel)); + writel(pchan->active_num, + apbh_regs + HW_APBHX_CHn_SEMA(channel)); + channel_bit = channel + (apbh_is_old ? BP_APBH_CTRL0_CLKGATE_CHANNEL : 0); + writel(1 << channel_bit, apbh_regs + HW_APBHX_CTRL0 + BIT_CLR); + } + + pchan->flags |= MXS_DMA_FLAGS_BUSY; + return 0; +} + +/* + * Disable a DMA channel. + * + * This function shuts down a DMA channel and marks it as "not busy." Any + * descriptors on the active list are immediately moved to the head of the + * "done" list, whether or not they have actually been processed by the + * hardware. The "ready" flags of these descriptors are NOT cleared, so they + * still appear to be active. + * + * This function immediately shuts down a DMA channel's hardware, aborting any + * I/O that may be in progress, potentially leaving I/O hardware in an undefined + * state. It is unwise to call this function if there is ANY chance the hardware + * is still processing a command. + */ +static int mxs_dma_disable(int channel) +{ + struct mxs_dma_chan *pchan; + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + int channel_bit, ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + pchan = mxs_dma_channels + channel; + + if (!(pchan->flags & MXS_DMA_FLAGS_BUSY)) + return -EINVAL; + + channel_bit = channel + (apbh_is_old ? BP_APBH_CTRL0_CLKGATE_CHANNEL : 0); + writel(1 << channel_bit, apbh_regs + HW_APBHX_CTRL0 + BIT_SET); + + pchan->flags &= ~MXS_DMA_FLAGS_BUSY; + pchan->active_num = 0; + pchan->pending_num = 0; + list_splice_init(&pchan->active, &pchan->done); + + return 0; +} + +/* + * Resets the DMA channel hardware. + */ +static int mxs_dma_reset(int channel) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + if (apbh_is_old) + writel(1 << (channel + BP_APBH_CTRL0_RESET_CHANNEL), + apbh_regs + HW_APBHX_CTRL0 + BIT_SET); + else + writel(1 << (channel + BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL), + apbh_regs + HW_APBHX_CHANNEL_CTRL + BIT_SET); + + return 0; +} + +/* + * Enable or disable DMA interrupt. + * + * This function enables the given DMA channel to interrupt the CPU. + */ +static int mxs_dma_enable_irq(int channel, int enable) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + if (enable) + writel(1 << (channel + BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN), + apbh_regs + HW_APBHX_CTRL1 + BIT_SET); + else + writel(1 << (channel + BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN), + apbh_regs + HW_APBHX_CTRL1 + BIT_CLR); + + return 0; +} + +/* + * Clear DMA interrupt. + * + * The software that is using the DMA channel must register to receive its + * interrupts and, when they arrive, must call this function to clear them. + */ +static int mxs_dma_ack_irq(int channel) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + writel(1 << channel, apbh_regs + HW_APBHX_CTRL1 + BIT_CLR); + writel(1 << channel, apbh_regs + HW_APBHX_CTRL2 + BIT_CLR); + + return 0; +} + +/* + * Request to reserve a DMA channel + */ +static int mxs_dma_request(int channel) +{ + struct mxs_dma_chan *pchan; + + if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS)) + return -EINVAL; + + pchan = mxs_dma_channels + channel; + if ((pchan->flags & MXS_DMA_FLAGS_VALID) != MXS_DMA_FLAGS_VALID) + return -ENODEV; + + if (pchan->flags & MXS_DMA_FLAGS_ALLOCATED) + return -EBUSY; + + pchan->flags |= MXS_DMA_FLAGS_ALLOCATED; + pchan->active_num = 0; + pchan->pending_num = 0; + + INIT_LIST_HEAD(&pchan->active); + INIT_LIST_HEAD(&pchan->done); + + return 0; +} + +/* + * Release a DMA channel. + * + * This function releases a DMA channel from its current owner. + * + * The channel will NOT be released if it's marked "busy" (see + * mxs_dma_enable()). + */ +static int mxs_dma_release(int channel) +{ + struct mxs_dma_chan *pchan; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + pchan = mxs_dma_channels + channel; + + if (pchan->flags & MXS_DMA_FLAGS_BUSY) + return -EBUSY; + + pchan->dev = 0; + pchan->active_num = 0; + pchan->pending_num = 0; + pchan->flags &= ~MXS_DMA_FLAGS_ALLOCATED; + + return 0; +} + +/* + * Allocate DMA descriptor + */ +struct mxs_dma_desc *mxs_dma_desc_alloc(void) +{ + struct mxs_dma_desc *pdesc; + + pdesc = dma_alloc_coherent(sizeof(struct mxs_dma_desc)); + + if (pdesc == NULL) + return NULL; + + memset(pdesc, 0, sizeof(*pdesc)); + pdesc->address = (dma_addr_t)pdesc; + + return pdesc; +}; + +/* + * Free DMA descriptor + */ +void mxs_dma_desc_free(struct mxs_dma_desc *pdesc) +{ + if (pdesc == NULL) + return; + + free(pdesc); +} + +/* + * Add a DMA descriptor to a channel. + * + * If the descriptor list for this channel is not empty, this function sets the + * CHAIN bit and the NEXTCMD_ADDR fields in the last descriptor's DMA command so + * it will chain to the new descriptor's command. + * + * Then, this function marks the new descriptor as "ready," adds it to the end + * of the active descriptor list, and increments the count of pending + * descriptors. + * + * The MXS platform DMA software imposes some rules on DMA commands to maintain + * important invariants. These rules are NOT checked, but they must be carefully + * applied by software that uses MXS DMA channels. + * + * Invariant: + * The DMA channel's hardware semaphore must reflect the number of DMA + * commands the hardware will process, but has not yet finished. + * + * Explanation: + * A DMA channel begins processing commands when its hardware semaphore is + * written with a value greater than zero, and it stops processing commands + * when the semaphore returns to zero. + * + * When a channel finishes a DMA command, it will decrement its semaphore if + * the DECREMENT_SEMAPHORE bit is set in that command's flags bits. + * + * In principle, it's not necessary for the DECREMENT_SEMAPHORE to be set, + * unless it suits the purposes of the software. For example, one could + * construct a series of five DMA commands, with the DECREMENT_SEMAPHORE + * bit set only in the last one. Then, setting the DMA channel's hardware + * semaphore to one would cause the entire series of five commands to be + * processed. However, this example would violate the invariant given above. + * + * Rule: + * ALL DMA commands MUST have the DECREMENT_SEMAPHORE bit set so that the DMA + * channel's hardware semaphore will be decremented EVERY time a command is + * processed. + */ +int mxs_dma_desc_append(int channel, struct mxs_dma_desc *pdesc) +{ + struct mxs_dma_chan *pchan; + struct mxs_dma_desc *last; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + pchan = mxs_dma_channels + channel; + + pdesc->cmd.next = mxs_dma_cmd_address(pdesc); + pdesc->flags |= MXS_DMA_DESC_FIRST | MXS_DMA_DESC_LAST; + + if (!list_empty(&pchan->active)) { + last = list_entry(pchan->active.prev, struct mxs_dma_desc, + node); + + pdesc->flags &= ~MXS_DMA_DESC_FIRST; + last->flags &= ~MXS_DMA_DESC_LAST; + + last->cmd.next = mxs_dma_cmd_address(pdesc); + last->cmd.data |= MXS_DMA_DESC_CHAIN; + } + pdesc->flags |= MXS_DMA_DESC_READY; + if (pdesc->flags & MXS_DMA_DESC_FIRST) + pchan->pending_num++; + list_add_tail(&pdesc->node, &pchan->active); + + return ret; +} + +/* + * Clean up processed DMA descriptors. + * + * This function removes processed DMA descriptors from the "active" list. Pass + * in a non-NULL list head to get the descriptors moved to your list. Pass NULL + * to get the descriptors moved to the channel's "done" list. Descriptors on + * the "done" list can be retrieved with mxs_dma_get_finished(). + * + * This function marks the DMA channel as "not busy" if no unprocessed + * descriptors remain on the "active" list. + */ +static int mxs_dma_finish(int channel, struct list_head *head) +{ + int sem; + struct mxs_dma_chan *pchan; + struct list_head *p, *q; + struct mxs_dma_desc *pdesc; + int ret; + + ret = mxs_dma_validate_chan(channel); + if (ret) + return ret; + + pchan = mxs_dma_channels + channel; + + sem = mxs_dma_read_semaphore(channel); + if (sem < 0) + return sem; + + if (sem == pchan->active_num) + return 0; + + list_for_each_safe(p, q, &pchan->active) { + if ((pchan->active_num) <= sem) + break; + + pdesc = list_entry(p, struct mxs_dma_desc, node); + pdesc->flags &= ~MXS_DMA_DESC_READY; + + if (head) + list_move_tail(p, head); + else + list_move_tail(p, &pchan->done); + + if (pdesc->flags & MXS_DMA_DESC_LAST) + pchan->active_num--; + } + + if (sem == 0) + pchan->flags &= ~MXS_DMA_FLAGS_BUSY; + + return 0; +} + +/* + * Wait for DMA channel to complete + */ +static int mxs_dma_wait_complete(uint32_t timeout, unsigned int chan) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + int ret; + + ret = mxs_dma_validate_chan(chan); + if (ret) + return ret; + + while (--timeout) { + if (readl(apbh_regs + HW_APBHX_CTRL1) & (1 << chan)) + break; + udelay(1); + } + + if (timeout == 0) { + ret = -ETIMEDOUT; + mxs_dma_reset(chan); + } + + return ret; +} + +/* + * Execute the DMA channel + */ +int mxs_dma_go(int chan) +{ + uint32_t timeout = 10000; + int ret; + + LIST_HEAD(tmp_desc_list); + + mxs_dma_enable_irq(chan, 1); + mxs_dma_enable(chan); + + /* Wait for DMA to finish. */ + ret = mxs_dma_wait_complete(timeout, chan); + + /* Clear out the descriptors we just ran. */ + mxs_dma_finish(chan, &tmp_desc_list); + + /* Shut the DMA channel down. */ + mxs_dma_ack_irq(chan); + mxs_dma_reset(chan); + mxs_dma_enable_irq(chan, 0); + mxs_dma_disable(chan); + + return ret; +} + +/* + * Initialize the DMA hardware + */ +int mxs_dma_init(void) +{ + void __iomem *apbh_regs = (void *)MXS_APBH_BASE; + struct mxs_dma_chan *pchan; + int ret, channel; + u32 val, reg; + + mxs_reset_block(apbh_regs, 0); + + /* HACK: Get CPUID and determine APBH version */ + val = readl(0x8001c310) >> 16; + if (val == 0x2800) + reg = MXS_APBH_BASE + 0x0800; + else + reg = MXS_APBH_BASE + 0x03f0; + + apbh_is_old = (readl((void *)reg) >> 24) < 3; + + writel(BM_APBH_CTRL0_APB_BURST8_EN, + apbh_regs + HW_APBHX_CTRL0 + BIT_SET); + + writel(BM_APBH_CTRL0_APB_BURST_EN, + apbh_regs + HW_APBHX_CTRL0 + BIT_SET); + + for (channel = 0; channel < MXS_MAX_DMA_CHANNELS; channel++) { + pchan = mxs_dma_channels + channel; + pchan->flags = MXS_DMA_FLAGS_VALID; + + ret = mxs_dma_request(channel); + + if (ret) { + printf("MXS DMA: Can't acquire DMA channel %i\n", + channel); + + goto err; + } + + mxs_dma_reset(channel); + mxs_dma_ack_irq(channel); + } + + return 0; + +err: + while (--channel >= 0) + mxs_dma_release(channel); + return ret; +} -- 1.7.10 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox