// SPDX-License-Identifier: GPL-2.0-or-later /* * Driver for the Loongson LS2X APB DMA Controller * * Copyright (C) 2017-2023 Loongson Corporation */ #include #include #include #include #include #include #include #include #include #include #include #include "dmaengine.h" #include "virt-dma.h" /* Global Configuration Register */ #define LDMA_ORDER_ERG 0x0 /* Bitfield definitions */ /* Bitfields in Global Configuration Register */ #define LDMA_64BIT_EN BIT(0) /* 1: 64 bit support */ #define LDMA_UNCOHERENT_EN BIT(1) /* 0: cache, 1: uncache */ #define LDMA_ASK_VALID BIT(2) #define LDMA_START BIT(3) /* DMA start operation */ #define LDMA_STOP BIT(4) /* DMA stop operation */ #define LDMA_CONFIG_MASK GENMASK(4, 0) /* DMA controller config bits mask */ /* Bitfields in ndesc_addr field of HW decriptor */ #define LDMA_DESC_EN BIT(0) /*1: The next descriptor is valid */ #define LDMA_DESC_ADDR_LOW GENMASK(31, 1) /* Bitfields in cmd field of HW decriptor */ #define LDMA_INT BIT(1) /* Enable DMA interrupts */ #define LDMA_DATA_DIRECTION BIT(12) /* 1: write to device, 0: read from device */ #define LDMA_SLAVE_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \ BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)) #define LDMA_MAX_TRANS_LEN U32_MAX /*-- descriptors -----------------------------------------------------*/ /* * struct ls2x_dma_hw_desc - DMA HW descriptor * @ndesc_addr: the next descriptor low address. * @mem_addr: memory low address. * @apb_addr: device buffer address. * @len: length of a piece of carried content, in words. * @step_len: length between two moved memory data blocks. * @step_times: number of blocks to be carried in a single DMA operation. * @cmd: descriptor command or state. * @stats: DMA status. * @high_ndesc_addr: the next descriptor high address. * @high_mem_addr: memory high address. * @reserved: reserved */ struct ls2x_dma_hw_desc { u32 ndesc_addr; u32 mem_addr; u32 apb_addr; u32 len; u32 step_len; u32 step_times; u32 cmd; u32 stats; u32 high_ndesc_addr; u32 high_mem_addr; u32 reserved[2]; } __packed; /* * struct ls2x_dma_sg - ls2x dma scatter gather entry * @hw: the pointer to DMA HW descriptor. * @llp: physical address of the DMA HW descriptor. * @phys: destination or source address(mem). * @len: number of Bytes to read. */ struct ls2x_dma_sg { struct ls2x_dma_hw_desc *hw; dma_addr_t llp; dma_addr_t phys; u32 len; }; /* * struct ls2x_dma_desc - software descriptor * @vdesc: pointer to the virtual dma descriptor. * @cyclic: flag to dma cyclic * @burst_size: burst size of transaction, in words. * @desc_num: number of sg entries. * @direction: transfer direction, to or from device. * @status: dma controller status. * @sg: array of sgs. */ struct ls2x_dma_desc { struct virt_dma_desc vdesc; bool cyclic; size_t burst_size; u32 desc_num; enum dma_transfer_direction direction; enum dma_status status; struct ls2x_dma_sg sg[] __counted_by(desc_num); }; /*-- Channels --------------------------------------------------------*/ /* * struct ls2x_dma_chan - internal representation of an LS2X APB DMA channel * @vchan: virtual dma channel entry. * @desc: pointer to the ls2x sw dma descriptor. * @pool: hw desc table * @irq: irq line * @sconfig: configuration for slave transfers, passed via .device_config */ struct ls2x_dma_chan { struct virt_dma_chan vchan; struct ls2x_dma_desc *desc; void *pool; int irq; struct dma_slave_config sconfig; }; /*-- Controller ------------------------------------------------------*/ /* * struct ls2x_dma_priv - LS2X APB DMAC specific information * @ddev: dmaengine dma_device object members * @dma_clk: DMAC clock source * @regs: memory mapped register base * @lchan: channel to store ls2x_dma_chan structures */ struct ls2x_dma_priv { struct dma_device ddev; struct clk *dma_clk; void __iomem *regs; struct ls2x_dma_chan lchan; }; /*-- Helper functions ------------------------------------------------*/ static inline struct ls2x_dma_desc *to_ldma_desc(struct virt_dma_desc *vdesc) { return container_of(vdesc, struct ls2x_dma_desc, vdesc); } static inline struct ls2x_dma_chan *to_ldma_chan(struct dma_chan *chan) { return container_of(chan, struct ls2x_dma_chan, vchan.chan); } static inline struct ls2x_dma_priv *to_ldma_priv(struct dma_device *ddev) { return container_of(ddev, struct ls2x_dma_priv, ddev); } static struct device *chan2dev(struct dma_chan *chan) { return &chan->dev->device; } static void ls2x_dma_desc_free(struct virt_dma_desc *vdesc) { struct ls2x_dma_chan *lchan = to_ldma_chan(vdesc->tx.chan); struct ls2x_dma_desc *desc = to_ldma_desc(vdesc); int i; for (i = 0; i < desc->desc_num; i++) { if (desc->sg[i].hw) dma_pool_free(lchan->pool, desc->sg[i].hw, desc->sg[i].llp); } kfree(desc); } static void ls2x_dma_write_cmd(struct ls2x_dma_chan *lchan, bool cmd) { struct ls2x_dma_priv *priv = to_ldma_priv(lchan->vchan.chan.device); u64 val; val = lo_hi_readq(priv->regs + LDMA_ORDER_ERG) & ~LDMA_CONFIG_MASK; val |= LDMA_64BIT_EN | cmd; lo_hi_writeq(val, priv->regs + LDMA_ORDER_ERG); } static void ls2x_dma_start_transfer(struct ls2x_dma_chan *lchan) { struct ls2x_dma_priv *priv = to_ldma_priv(lchan->vchan.chan.device); struct ls2x_dma_sg *ldma_sg; struct virt_dma_desc *vdesc; u64 val; /* Get the next descriptor */ vdesc = vchan_next_desc(&lchan->vchan); if (!vdesc) { lchan->desc = NULL; return; } list_del(&vdesc->node); lchan->desc = to_ldma_desc(vdesc); ldma_sg = &lchan->desc->sg[0]; /* Start DMA */ lo_hi_writeq(0, priv->regs + LDMA_ORDER_ERG); val = (ldma_sg->llp & ~LDMA_CONFIG_MASK) | LDMA_64BIT_EN | LDMA_START; lo_hi_writeq(val, priv->regs + LDMA_ORDER_ERG); } static size_t ls2x_dmac_detect_burst(struct ls2x_dma_chan *lchan) { u32 maxburst, buswidth; /* Reject definitely invalid configurations */ if ((lchan->sconfig.src_addr_width & LDMA_SLAVE_BUSWIDTHS) && (lchan->sconfig.dst_addr_width & LDMA_SLAVE_BUSWIDTHS)) return 0; if (lchan->sconfig.direction == DMA_MEM_TO_DEV) { maxburst = lchan->sconfig.dst_maxburst; buswidth = lchan->sconfig.dst_addr_width; } else { maxburst = lchan->sconfig.src_maxburst; buswidth = lchan->sconfig.src_addr_width; } /* If maxburst is zero, fallback to LDMA_MAX_TRANS_LEN */ return maxburst ? (maxburst * buswidth) >> 2 : LDMA_MAX_TRANS_LEN; } static void ls2x_dma_fill_desc(struct ls2x_dma_chan *lchan, u32 sg_index, struct ls2x_dma_desc *desc) { struct ls2x_dma_sg *ldma_sg = &desc->sg[sg_index]; u32 num_segments, segment_size; if (desc->direction == DMA_MEM_TO_DEV) { ldma_sg->hw->cmd = LDMA_INT | LDMA_DATA_DIRECTION; ldma_sg->hw->apb_addr = lchan->sconfig.dst_addr; } else { ldma_sg->hw->cmd = LDMA_INT; ldma_sg->hw->apb_addr = lchan->sconfig.src_addr; } ldma_sg->hw->mem_addr = lower_32_bits(ldma_sg->phys); ldma_sg->hw->high_mem_addr = upper_32_bits(ldma_sg->phys); /* Split into multiple equally sized segments if necessary */ num_segments = DIV_ROUND_UP((ldma_sg->len + 3) >> 2, desc->burst_size); segment_size = DIV_ROUND_UP((ldma_sg->len + 3) >> 2, num_segments); /* Word count register takes input in words */ ldma_sg->hw->len = segment_size; ldma_sg->hw->step_times = num_segments; ldma_sg->hw->step_len = 0; /* lets make a link list */ if (sg_index) { desc->sg[sg_index - 1].hw->ndesc_addr = ldma_sg->llp | LDMA_DESC_EN; desc->sg[sg_index - 1].hw->high_ndesc_addr = upper_32_bits(ldma_sg->llp); } } /*-- DMA Engine API --------------------------------------------------*/ /* * ls2x_dma_alloc_chan_resources - allocate resources for DMA channel * @chan: allocate descriptor resources for this channel * * return - the number of allocated descriptors */ static int ls2x_dma_alloc_chan_resources(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); /* Create a pool of consistent memory blocks for hardware descriptors */ lchan->pool = dma_pool_create(dev_name(chan2dev(chan)), chan->device->dev, PAGE_SIZE, __alignof__(struct ls2x_dma_hw_desc), 0); if (!lchan->pool) { dev_err(chan2dev(chan), "No memory for descriptors\n"); return -ENOMEM; } return 1; } /* * ls2x_dma_free_chan_resources - free all channel resources * @chan: DMA channel */ static void ls2x_dma_free_chan_resources(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); vchan_free_chan_resources(to_virt_chan(chan)); dma_pool_destroy(lchan->pool); lchan->pool = NULL; } /* * ls2x_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction * @chan: DMA channel * @sgl: scatterlist to transfer to/from * @sg_len: number of entries in @scatterlist * @direction: DMA direction * @flags: tx descriptor status flags * @context: transaction context (ignored) * * Return: Async transaction descriptor on success and NULL on failure */ static struct dma_async_tx_descriptor * ls2x_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, u32 sg_len, enum dma_transfer_direction direction, unsigned long flags, void *context) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); struct ls2x_dma_desc *desc; struct scatterlist *sg; size_t burst_size; int i; if (unlikely(!sg_len || !is_slave_direction(direction))) return NULL; burst_size = ls2x_dmac_detect_burst(lchan); if (!burst_size) return NULL; desc = kzalloc(struct_size(desc, sg, sg_len), GFP_NOWAIT); if (!desc) return NULL; desc->desc_num = sg_len; desc->direction = direction; desc->burst_size = burst_size; for_each_sg(sgl, sg, sg_len, i) { struct ls2x_dma_sg *ldma_sg = &desc->sg[i]; /* Allocate DMA capable memory for hardware descriptor */ ldma_sg->hw = dma_pool_alloc(lchan->pool, GFP_NOWAIT, &ldma_sg->llp); if (!ldma_sg->hw) { desc->desc_num = i; ls2x_dma_desc_free(&desc->vdesc); return NULL; } ldma_sg->phys = sg_dma_address(sg); ldma_sg->len = sg_dma_len(sg); ls2x_dma_fill_desc(lchan, i, desc); } /* Setting the last descriptor enable bit */ desc->sg[sg_len - 1].hw->ndesc_addr &= ~LDMA_DESC_EN; desc->status = DMA_IN_PROGRESS; return vchan_tx_prep(&lchan->vchan, &desc->vdesc, flags); } /* * ls2x_dma_prep_dma_cyclic - prepare the cyclic DMA transfer * @chan: the DMA channel to prepare * @buf_addr: physical DMA address where the buffer starts * @buf_len: total number of bytes for the entire buffer * @period_len: number of bytes for each period * @direction: transfer direction, to or from device * @flags: tx descriptor status flags * * Return: Async transaction descriptor on success and NULL on failure */ static struct dma_async_tx_descriptor * ls2x_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_transfer_direction direction, unsigned long flags) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); struct ls2x_dma_desc *desc; size_t burst_size; u32 num_periods; int i; if (unlikely(!buf_len || !period_len)) return NULL; if (unlikely(!is_slave_direction(direction))) return NULL; burst_size = ls2x_dmac_detect_burst(lchan); if (!burst_size) return NULL; num_periods = buf_len / period_len; desc = kzalloc(struct_size(desc, sg, num_periods), GFP_NOWAIT); if (!desc) return NULL; desc->desc_num = num_periods; desc->direction = direction; desc->burst_size = burst_size; /* Build cyclic linked list */ for (i = 0; i < num_periods; i++) { struct ls2x_dma_sg *ldma_sg = &desc->sg[i]; /* Allocate DMA capable memory for hardware descriptor */ ldma_sg->hw = dma_pool_alloc(lchan->pool, GFP_NOWAIT, &ldma_sg->llp); if (!ldma_sg->hw) { desc->desc_num = i; ls2x_dma_desc_free(&desc->vdesc); return NULL; } ldma_sg->phys = buf_addr + period_len * i; ldma_sg->len = period_len; ls2x_dma_fill_desc(lchan, i, desc); } /* Lets make a cyclic list */ desc->sg[num_periods - 1].hw->ndesc_addr = desc->sg[0].llp | LDMA_DESC_EN; desc->sg[num_periods - 1].hw->high_ndesc_addr = upper_32_bits(desc->sg[0].llp); desc->cyclic = true; desc->status = DMA_IN_PROGRESS; return vchan_tx_prep(&lchan->vchan, &desc->vdesc, flags); } /* * ls2x_slave_config - set slave configuration for channel * @chan: dma channel * @cfg: slave configuration * * Sets slave configuration for channel */ static int ls2x_dma_slave_config(struct dma_chan *chan, struct dma_slave_config *config) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); memcpy(&lchan->sconfig, config, sizeof(*config)); return 0; } /* * ls2x_dma_issue_pending - push pending transactions to the hardware * @chan: channel * * When this function is called, all pending transactions are pushed to the * hardware and executed. */ static void ls2x_dma_issue_pending(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); unsigned long flags; spin_lock_irqsave(&lchan->vchan.lock, flags); if (vchan_issue_pending(&lchan->vchan) && !lchan->desc) ls2x_dma_start_transfer(lchan); spin_unlock_irqrestore(&lchan->vchan.lock, flags); } /* * ls2x_dma_terminate_all - terminate all transactions * @chan: channel * * Stops all DMA transactions. */ static int ls2x_dma_terminate_all(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); unsigned long flags; LIST_HEAD(head); spin_lock_irqsave(&lchan->vchan.lock, flags); /* Setting stop cmd */ ls2x_dma_write_cmd(lchan, LDMA_STOP); if (lchan->desc) { vchan_terminate_vdesc(&lchan->desc->vdesc); lchan->desc = NULL; } vchan_get_all_descriptors(&lchan->vchan, &head); spin_unlock_irqrestore(&lchan->vchan.lock, flags); vchan_dma_desc_free_list(&lchan->vchan, &head); return 0; } /* * ls2x_dma_synchronize - Synchronizes the termination of transfers to the * current context. * @chan: channel */ static void ls2x_dma_synchronize(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); vchan_synchronize(&lchan->vchan); } static int ls2x_dma_pause(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); unsigned long flags; spin_lock_irqsave(&lchan->vchan.lock, flags); if (lchan->desc && lchan->desc->status == DMA_IN_PROGRESS) { ls2x_dma_write_cmd(lchan, LDMA_STOP); lchan->desc->status = DMA_PAUSED; } spin_unlock_irqrestore(&lchan->vchan.lock, flags); return 0; } static int ls2x_dma_resume(struct dma_chan *chan) { struct ls2x_dma_chan *lchan = to_ldma_chan(chan); unsigned long flags; spin_lock_irqsave(&lchan->vchan.lock, flags); if (lchan->desc && lchan->desc->status == DMA_PAUSED) { lchan->desc->status = DMA_IN_PROGRESS; ls2x_dma_write_cmd(lchan, LDMA_START); } spin_unlock_irqrestore(&lchan->vchan.lock, flags); return 0; } /* * ls2x_dma_isr - LS2X DMA Interrupt handler * @irq: IRQ number * @dev_id: Pointer to ls2x_dma_chan * * Return: IRQ_HANDLED/IRQ_NONE */ static irqreturn_t ls2x_dma_isr(int irq, void *dev_id) { struct ls2x_dma_chan *lchan = dev_id; struct ls2x_dma_desc *desc; spin_lock(&lchan->vchan.lock); desc = lchan->desc; if (desc) { if (desc->cyclic) { vchan_cyclic_callback(&desc->vdesc); } else { desc->status = DMA_COMPLETE; vchan_cookie_complete(&desc->vdesc); ls2x_dma_start_transfer(lchan); } /* ls2x_dma_start_transfer() updates lchan->desc */ if (!lchan->desc) ls2x_dma_write_cmd(lchan, LDMA_STOP); } spin_unlock(&lchan->vchan.lock); return IRQ_HANDLED; } static int ls2x_dma_chan_init(struct platform_device *pdev, struct ls2x_dma_priv *priv) { struct ls2x_dma_chan *lchan = &priv->lchan; struct device *dev = &pdev->dev; int ret; lchan->irq = platform_get_irq(pdev, 0); if (lchan->irq < 0) return lchan->irq; ret = devm_request_irq(dev, lchan->irq, ls2x_dma_isr, IRQF_TRIGGER_RISING, dev_name(&pdev->dev), lchan); if (ret) return ret; /* Initialize channels related values */ INIT_LIST_HEAD(&priv->ddev.channels); lchan->vchan.desc_free = ls2x_dma_desc_free; vchan_init(&lchan->vchan, &priv->ddev); return 0; } /* * ls2x_dma_probe - Driver probe function * @pdev: Pointer to the platform_device structure * * Return: '0' on success and failure value on error */ static int ls2x_dma_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct ls2x_dma_priv *priv; struct dma_device *ddev; int ret; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->regs = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(priv->regs)) return dev_err_probe(dev, PTR_ERR(priv->regs), "devm_platform_ioremap_resource failed.\n"); priv->dma_clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(priv->dma_clk)) return dev_err_probe(dev, PTR_ERR(priv->dma_clk), "devm_clk_get failed.\n"); ret = clk_prepare_enable(priv->dma_clk); if (ret) return dev_err_probe(dev, ret, "clk_prepare_enable failed.\n"); ret = ls2x_dma_chan_init(pdev, priv); if (ret) goto disable_clk; ddev = &priv->ddev; ddev->dev = dev; dma_cap_zero(ddev->cap_mask); dma_cap_set(DMA_SLAVE, ddev->cap_mask); dma_cap_set(DMA_CYCLIC, ddev->cap_mask); ddev->device_alloc_chan_resources = ls2x_dma_alloc_chan_resources; ddev->device_free_chan_resources = ls2x_dma_free_chan_resources; ddev->device_tx_status = dma_cookie_status; ddev->device_issue_pending = ls2x_dma_issue_pending; ddev->device_prep_slave_sg = ls2x_dma_prep_slave_sg; ddev->device_prep_dma_cyclic = ls2x_dma_prep_dma_cyclic; ddev->device_config = ls2x_dma_slave_config; ddev->device_terminate_all = ls2x_dma_terminate_all; ddev->device_synchronize = ls2x_dma_synchronize; ddev->device_pause = ls2x_dma_pause; ddev->device_resume = ls2x_dma_resume; ddev->src_addr_widths = LDMA_SLAVE_BUSWIDTHS; ddev->dst_addr_widths = LDMA_SLAVE_BUSWIDTHS; ddev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); ret = dma_async_device_register(&priv->ddev); if (ret < 0) goto disable_clk; ret = of_dma_controller_register(dev->of_node, of_dma_xlate_by_chan_id, priv); if (ret < 0) goto unregister_dmac; platform_set_drvdata(pdev, priv); dev_info(dev, "Loongson LS2X APB DMA driver registered successfully.\n"); return 0; unregister_dmac: dma_async_device_unregister(&priv->ddev); disable_clk: clk_disable_unprepare(priv->dma_clk); return ret; } /* * ls2x_dma_remove - Driver remove function * @pdev: Pointer to the platform_device structure */ static void ls2x_dma_remove(struct platform_device *pdev) { struct ls2x_dma_priv *priv = platform_get_drvdata(pdev); of_dma_controller_free(pdev->dev.of_node); dma_async_device_unregister(&priv->ddev); clk_disable_unprepare(priv->dma_clk); } static const struct of_device_id ls2x_dma_of_match_table[] = { { .compatible = "loongson,ls2k1000-apbdma" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, ls2x_dma_of_match_table); static struct platform_driver ls2x_dmac_driver = { .probe = ls2x_dma_probe, .remove_new = ls2x_dma_remove, .driver = { .name = "ls2x-apbdma", .of_match_table = ls2x_dma_of_match_table, }, }; module_platform_driver(ls2x_dmac_driver); MODULE_DESCRIPTION("Loongson LS2X APB DMA Controller driver"); MODULE_AUTHOR("Loongson Technology Corporation Limited"); MODULE_LICENSE("GPL");