--- /dev/null
+/*
+ * Freescale i.MX28 APBH DMA driver
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <linux/list.h>
+
+#include <common.h>
+#include <malloc.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/imx-common/dma.h>
+#include <asm/imx-common/regs-apbh.h>
+
+static struct mxs_dma_chan mxs_dma_channels[MXS_MAX_DMA_CHANNELS];
+
+/*
+ * 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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ uint32_t tmp;
+ int ret;
+
+ ret = mxs_dma_validate_chan(channel);
+ if (ret)
+ return ret;
+
+ tmp = readl(&apbh_regs->ch[channel].hw_apbh_ch_sema);
+
+ tmp &= APBH_CHn_SEMA_PHORE_MASK;
+ tmp >>= APBH_CHn_SEMA_PHORE_OFFSET;
+
+ return tmp;
+}
+
+#ifndef CONFIG_SYS_DCACHE_OFF
+void mxs_dma_flush_desc(struct mxs_dma_desc *desc)
+{
+ uint32_t addr;
+ uint32_t size;
+
+ addr = (uint32_t)desc;
+ size = roundup(sizeof(struct mxs_dma_desc), MXS_DMA_ALIGNMENT);
+
+ flush_dcache_range(addr, addr + size);
+}
+#else
+inline void mxs_dma_flush_desc(struct mxs_dma_desc *desc) {}
+#endif
+
+/*
+ * 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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ unsigned int sem;
+ struct mxs_dma_chan *pchan;
+ struct mxs_dma_desc *pdesc;
+ int 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->ch[channel].hw_apbh_ch_nxtcmdar);
+ }
+ writel(pchan->pending_num,
+ &apbh_regs->ch[channel].hw_apbh_ch_sema);
+ 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->ch[channel].hw_apbh_ch_nxtcmdar);
+ writel(pchan->active_num,
+ &apbh_regs->ch[channel].hw_apbh_ch_sema);
+ writel(1 << (channel + APBH_CTRL0_CLKGATE_CHANNEL_OFFSET),
+ &apbh_regs->hw_apbh_ctrl0_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;
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ 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 -EINVAL;
+
+ writel(1 << (channel + APBH_CTRL0_CLKGATE_CHANNEL_OFFSET),
+ &apbh_regs->hw_apbh_ctrl0_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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ int ret;
+#if defined(CONFIG_MX23)
+ uint32_t setreg = (uint32_t)(&apbh_regs->hw_apbh_ctrl0_set);
+ uint32_t offset = APBH_CTRL0_RESET_CHANNEL_OFFSET;
+#elif (defined(CONFIG_MX28) || defined(CONFIG_MX6))
+ uint32_t setreg = (uint32_t)(&apbh_regs->hw_apbh_channel_ctrl_set);
+ uint32_t offset = APBH_CHANNEL_CTRL_RESET_CHANNEL_OFFSET;
+#endif
+
+ ret = mxs_dma_validate_chan(channel);
+ if (ret)
+ return ret;
+
+ writel(1 << (channel + offset), setreg);
+
+ 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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ int ret;
+
+ ret = mxs_dma_validate_chan(channel);
+ if (ret)
+ return ret;
+
+ if (enable)
+ writel(1 << (channel + APBH_CTRL1_CH_CMDCMPLT_IRQ_EN_OFFSET),
+ &apbh_regs->hw_apbh_ctrl1_set);
+ else
+ writel(1 << (channel + APBH_CTRL1_CH_CMDCMPLT_IRQ_EN_OFFSET),
+ &apbh_regs->hw_apbh_ctrl1_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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ int ret;
+
+ ret = mxs_dma_validate_chan(channel);
+ if (ret)
+ return ret;
+
+ writel(1 << channel, &apbh_regs->hw_apbh_ctrl1_clr);
+ writel(1 << channel, &apbh_regs->hw_apbh_ctrl2_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()).
+ */
+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;
+ uint32_t size;
+
+ size = roundup(sizeof(struct mxs_dma_desc), MXS_DMA_ALIGNMENT);
+ pdesc = memalign(MXS_DMA_ALIGNMENT, size);
+
+ 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;
+
+ mxs_dma_flush_desc(last);
+ }
+ pdesc->flags |= MXS_DMA_DESC_READY;
+ if (pdesc->flags & MXS_DMA_DESC_FIRST)
+ pchan->pending_num++;
+ list_add_tail(&pdesc->node, &pchan->active);
+
+ mxs_dma_flush_desc(pdesc);
+
+ 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)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+ int ret;
+
+ ret = mxs_dma_validate_chan(chan);
+ if (ret)
+ return ret;
+
+ if (mxs_wait_mask_set(&apbh_regs->hw_apbh_ctrl1_reg,
+ 1 << chan, timeout)) {
+ ret = -ETIMEDOUT;
+ mxs_dma_reset(chan);
+ }
+
+ return ret;
+}
+
+/*
+ * Execute the DMA channel
+ */
+int mxs_dma_go(int chan)
+{
+ uint32_t timeout = 10000000;
+ 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;
+}
+
+/*
+ * Execute a continuously running circular DMA descriptor.
+ * NOTE: This is not intended for general use, but rather
+ * for the LCD driver in Smart-LCD mode. It allows
+ * continuous triggering of the RUN bit there.
+ */
+void mxs_dma_circ_start(int chan, struct mxs_dma_desc *pdesc)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+
+ mxs_dma_flush_desc(pdesc);
+
+ mxs_dma_enable_irq(chan, 1);
+
+ writel(mxs_dma_cmd_address(pdesc),
+ &apbh_regs->ch[chan].hw_apbh_ch_nxtcmdar);
+ writel(1, &apbh_regs->ch[chan].hw_apbh_ch_sema);
+ writel(1 << (chan + APBH_CTRL0_CLKGATE_CHANNEL_OFFSET),
+ &apbh_regs->hw_apbh_ctrl0_clr);
+}
+
+/*
+ * Initialize the DMA hardware
+ */
+void mxs_dma_init(void)
+{
+ struct mxs_apbh_regs *apbh_regs =
+ (struct mxs_apbh_regs *)MXS_APBH_BASE;
+
+ mxs_reset_block(&apbh_regs->hw_apbh_ctrl0_reg);
+
+#ifdef CONFIG_APBH_DMA_BURST8
+ writel(APBH_CTRL0_AHB_BURST8_EN,
+ &apbh_regs->hw_apbh_ctrl0_set);
+#else
+ writel(APBH_CTRL0_AHB_BURST8_EN,
+ &apbh_regs->hw_apbh_ctrl0_clr);
+#endif
+
+#ifdef CONFIG_APBH_DMA_BURST
+ writel(APBH_CTRL0_APB_BURST_EN,
+ &apbh_regs->hw_apbh_ctrl0_set);
+#else
+ writel(APBH_CTRL0_APB_BURST_EN,
+ &apbh_regs->hw_apbh_ctrl0_clr);
+#endif
+}
+
+int mxs_dma_init_channel(int channel)
+{
+ struct mxs_dma_chan *pchan;
+ int ret;
+
+ 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);
+ return ret;
+ }
+
+ mxs_dma_reset(channel);
+ mxs_dma_ack_irq(channel);
+
+ return 0;
+}
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