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Message-ID: <ZhKPsKFyaXFliJP4@matsya>
Date: Sun, 7 Apr 2024 17:51:04 +0530
From: Vinod Koul <vkoul@...nel.org>
To: Kelvin Cao <kelvin.cao@...rochip.com>
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
logang@...tatee.com, George.Ge@...rochip.com,
christophe.jaillet@...adoo.fr, hch@...radead.org
Subject: Re: [PATCH v8 1/1] dmaengine: switchtec-dma: Introduce Switchtec DMA
engine PCI driver
On 18-03-24, 09:33, Kelvin Cao wrote:
> Some Switchtec Switches can expose DMA engines via extra PCI functions
> on the upstream ports. At most one such function can be supported on
> each upstream port. Each function can have one or more DMA channels.
>
> Implement core PCI driver skeleton and DMA engine callbacks.
can you please split the two, pci parts and dma parts for review
>
> Signed-off-by: Kelvin Cao <kelvin.cao@...rochip.com>
> Co-developed-by: George Ge <george.ge@...rochip.com>
> Signed-off-by: George Ge <george.ge@...rochip.com>
> ---
> MAINTAINERS | 6 +
> drivers/dma/Kconfig | 9 +
> drivers/dma/Makefile | 1 +
> drivers/dma/switchtec_dma.c | 1546 +++++++++++++++++++++++++++++++++++
> 4 files changed, 1562 insertions(+)
> create mode 100644 drivers/dma/switchtec_dma.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 1aabf1c15bb3..03b254487a3f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21156,6 +21156,12 @@ S: Supported
> F: include/net/switchdev.h
> F: net/switchdev/
>
> +SWITCHTEC DMA DRIVER
> +M: Kelvin Cao <kelvin.cao@...rochip.com>
> +L: dmaengine@...r.kernel.org
> +S: Maintained
> +F: drivers/dma/switchtec_dma.c
> +
> SY8106A REGULATOR DRIVER
> M: Icenowy Zheng <icenowy@...c.io>
> S: Maintained
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index e928f2ca0f1e..578a1d7fabba 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -608,6 +608,15 @@ config SPRD_DMA
> help
> Enable support for the on-chip DMA controller on Spreadtrum platform.
>
> +config SWITCHTEC_DMA
> + tristate "Switchtec PSX/PFX Switch DMA Engine Support"
> + depends on PCI
> + select DMA_ENGINE
> + help
> + Some Switchtec PSX/PFX PCIe Switches support additional DMA engines.
> + These are exposed via an extra function on the switch's upstream
> + port.
> +
> config TXX9_DMAC
> tristate "Toshiba TXx9 SoC DMA support"
> depends on MACH_TX49XX
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index dfd40d14e408..bdfb25d49dba 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -72,6 +72,7 @@ obj-$(CONFIG_STM32_DMA) += stm32-dma.o
> obj-$(CONFIG_STM32_DMAMUX) += stm32-dmamux.o
> obj-$(CONFIG_STM32_MDMA) += stm32-mdma.o
> obj-$(CONFIG_SPRD_DMA) += sprd-dma.o
> +obj-$(CONFIG_SWITCHTEC_DMA) += switchtec_dma.o
> obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
> obj-$(CONFIG_TEGRA186_GPC_DMA) += tegra186-gpc-dma.o
> obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
> diff --git a/drivers/dma/switchtec_dma.c b/drivers/dma/switchtec_dma.c
> new file mode 100644
> index 000000000000..3eced3320f9a
> --- /dev/null
> +++ b/drivers/dma/switchtec_dma.c
> @@ -0,0 +1,1546 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Microchip Switchtec(tm) DMA Controller Driver
> + * Copyright (c) 2023, Kelvin Cao <kelvin.cao@...rochip.com>
> + * Copyright (c) 2023, Microchip Corporation
2024
> + */
> +
> +#include <linux/circ_buf.h>
> +#include <linux/dmaengine.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/delay.h>
> +#include <linux/iopoll.h>
> +
> +#include "dmaengine.h"
> +
> +MODULE_DESCRIPTION("Switchtec PCIe Switch DMA Engine");
> +MODULE_VERSION("0.1");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Kelvin Cao");
> +
> +#define SWITCHTEC_DMAC_CHAN_CTRL_OFFSET 0x1000
> +#define SWITCHTEC_DMAC_CHAN_CFG_STS_OFFSET 0x160000
> +
> +#define SWITCHTEC_DMA_CHAN_HW_REGS_SIZE 0x1000
> +#define SWITCHTEC_DMA_CHAN_FW_REGS_SIZE 0x80
> +
> +#define SWITCHTEC_REG_CAP 0x80
> +#define SWITCHTEC_REG_CHAN_CNT 0x84
> +#define SWITCHTEC_REG_TAG_LIMIT 0x90
> +#define SWITCHTEC_REG_CHAN_STS_VEC 0x94
> +#define SWITCHTEC_REG_SE_BUF_CNT 0x98
> +#define SWITCHTEC_REG_SE_BUF_BASE 0x9a
> +
> +#define SWITCHTEC_DESC_MAX_SIZE 0x100000
> +
> +#define SWITCHTEC_CHAN_CTRL_PAUSE BIT(0)
> +#define SWITCHTEC_CHAN_CTRL_HALT BIT(1)
> +#define SWITCHTEC_CHAN_CTRL_RESET BIT(2)
> +#define SWITCHTEC_CHAN_CTRL_ERR_PAUSE BIT(3)
> +
> +#define SWITCHTEC_CHAN_STS_PAUSED BIT(9)
> +#define SWITCHTEC_CHAN_STS_HALTED BIT(10)
> +#define SWITCHTEC_CHAN_STS_PAUSED_MASK GENMASK(29, 13)
> +
> +static const char * const channel_status_str[] = {
> + [13] = "received a VDM with length error status",
> + [14] = "received a VDM or Cpl with Unsupported Request error status",
> + [15] = "received a VDM or Cpl with Completion Abort error status",
> + [16] = "received a VDM with ECRC error status",
> + [17] = "received a VDM with EP error status",
> + [18] = "received a VDM with Reserved Cpl error status",
> + [19] = "received only part of split SE CplD",
> + [20] = "the ISP_DMAC detected a Completion Time Out",
> + [21] = "received a Cpl with Unsupported Request status",
> + [22] = "received a Cpl with Completion Abort status",
> + [23] = "received a Cpl with a reserved status",
> + [24] = "received a TLP with ECRC error status in its metadata",
> + [25] = "received a TLP with the EP bit set in the header",
> + [26] = "the ISP_DMAC tried to process a SE with an invalid Connection ID",
> + [27] = "the ISP_DMAC tried to process a SE with an invalid Remote Host interrupt",
> + [28] = "a reserved opcode was detected in an SE",
> + [29] = "received a SE Cpl with error status",
> +};
> +
> +struct chan_hw_regs {
> + u16 cq_head;
> + u16 rsvd1;
> + u16 sq_tail;
> + u16 rsvd2;
> + u8 ctrl;
> + u8 rsvd3[3];
> + u16 status;
> + u16 rsvd4;
> +};
> +
> +enum {
> + PERF_BURST_SCALE = 0x1,
> + PERF_BURST_SIZE = 0x6,
> + PERF_INTERVAL = 0x0,
> + PERF_MRRS = 0x3,
> + PERF_ARB_WEIGHT = 0x1,
> +};
Does this represt HW values, or a SW enum? can this be sorted?
Why PERF_ARB_WEIGHT and PERF_BURST_SCALE have same values?
> +
> +enum {
> + PERF_BURST_SCALE_SHIFT = 0x2,
> + PERF_BURST_SCALE_MASK = 0x3,
> + PERF_MRRS_SHIFT = 0x4,
> + PERF_MRRS_MASK = 0x7,
> + PERF_INTERVAL_SHIFT = 0x8,
> + PERF_INTERVAL_MASK = 0x7,
> + PERF_BURST_SIZE_SHIFT = 0xc,
> + PERF_BURST_SIZE_MASK = 0x7,
> + PERF_ARB_WEIGHT_SHIFT = 0x18,
> + PERF_ARB_WEIGHT_MASK = 0xff,
This look like register bitfields? Consider using GENMASK for defining
and drop the shifts, use FIELD_PREP, FIELD_GET instead
> +};
> +
> +enum {
> + PERF_MIN_INTERVAL = 0,
> + PERF_MAX_INTERVAL = 0x7,
> + PERF_MIN_BURST_SIZE = 0,
> + PERF_MAX_BURST_SIZE = 0x7,
> + PERF_MIN_BURST_SCALE = 0,
> + PERF_MAX_BURST_SCALE = 0x2,
> + PERF_MIN_MRRS = 0,
> + PERF_MAX_MRRS = 0x7,
> +};
> +
> +enum {
> + SE_BUF_BASE_SHIFT = 0x2,
> + SE_BUF_BASE_MASK = 0x1ff,
> + SE_BUF_LEN_SHIFT = 0xc,
> + SE_BUF_LEN_MASK = 0x1ff,
> + SE_THRESH_SHIFT = 0x17,
> + SE_THRESH_MASK = 0x1ff,
> +};
> +
> +#define SWITCHTEC_CHAN_ENABLE BIT(1)
> +
> +struct chan_fw_regs {
> + u32 valid_en_se;
> + u32 cq_base_lo;
> + u32 cq_base_hi;
> + u16 cq_size;
> + u16 rsvd1;
> + u32 sq_base_lo;
> + u32 sq_base_hi;
> + u16 sq_size;
> + u16 rsvd2;
> + u32 int_vec;
> + u32 perf_cfg;
> + u32 rsvd3;
> + u32 perf_latency_selector;
> + u32 perf_fetched_se_cnt_lo;
> + u32 perf_fetched_se_cnt_hi;
> + u32 perf_byte_cnt_lo;
> + u32 perf_byte_cnt_hi;
> + u32 rsvd4;
> + u16 perf_se_pending;
> + u16 perf_se_buf_empty;
> + u32 perf_chan_idle;
> + u32 perf_lat_max;
> + u32 perf_lat_min;
> + u32 perf_lat_last;
> + u16 sq_current;
> + u16 sq_phase;
> + u16 cq_current;
> + u16 cq_phase;
> +};
> +
> +enum cmd {
> + CMD_GET_HOST_LIST = 1,
> + CMD_REGISTER_BUF = 2,
> + CMD_UNREGISTER_BUF = 3,
> + CMD_GET_BUF_LIST = 4,
> + CMD_GET_OWN_BUF_LIST = 5,
> +};
> +
> +enum cmd_status {
> + CMD_STATUS_IDLE = 0,
> + CMD_STATUS_INPROGRESS = 0x1,
> + CMD_STATUS_DONE = 0x2,
> + CMD_STATUS_ERROR = 0xFF,
lower case hex please
> +};
> +
> +struct switchtec_dma_chan {
> + struct switchtec_dma_dev *swdma_dev;
> + struct dma_chan dma_chan;
> + struct chan_hw_regs __iomem *mmio_chan_hw;
> + struct chan_fw_regs __iomem *mmio_chan_fw;
> +
> + /* Serialize hardware control register access */
> + spinlock_t hw_ctrl_lock;
> +
> + struct tasklet_struct desc_task;
> +
> + /* Serialize descriptor preparation */
> + spinlock_t submit_lock;
> + bool ring_active;
> + int cid;
> +
> + /* Serialize completion processing */
> + spinlock_t complete_lock;
> + bool comp_ring_active;
> +
> + /* channel index and irq */
> + int index;
> + int irq;
> +
> + /*
> + * In driver context, head is advanced by producer while
> + * tail is advanced by consumer.
> + */
> +
> + /* the head and tail for both desc_ring and hw_sq */
> + int head;
> + int tail;
> + int phase_tag;
> + struct switchtec_dma_desc **desc_ring;
> + struct switchtec_dma_hw_se_desc *hw_sq;
> + dma_addr_t dma_addr_sq;
> +
> + /* the tail for hw_cq */
> + int cq_tail;
> + struct switchtec_dma_hw_ce *hw_cq;
> + dma_addr_t dma_addr_cq;
> +
> + struct list_head list;
> +};
> +
> +struct switchtec_dma_dev {
> + struct dma_device dma_dev;
> + struct pci_dev __rcu *pdev;
> + struct switchtec_dma_chan **swdma_chans;
> + int chan_cnt;
> + int chan_status_irq;
> + void __iomem *bar;
> + struct tasklet_struct chan_status_task;
> +};
> +
> +static struct switchtec_dma_chan *to_switchtec_dma_chan(struct dma_chan *c)
> +{
> + return container_of(c, struct switchtec_dma_chan, dma_chan);
> +}
> +
> +static struct device *to_chan_dev(struct switchtec_dma_chan *swdma_chan)
> +{
> + return &swdma_chan->dma_chan.dev->device;
> +}
> +
> +enum switchtec_dma_opcode {
> + SWITCHTEC_DMA_OPC_MEMCPY = 0,
> + SWITCHTEC_DMA_OPC_RDIMM = 0x1,
> + SWITCHTEC_DMA_OPC_WRIMM = 0x2,
> + SWITCHTEC_DMA_OPC_RHI = 0x6,
> + SWITCHTEC_DMA_OPC_NOP = 0x7,
> +};
> +
> +struct switchtec_dma_hw_se_desc {
> + u8 opc;
> + u8 ctrl;
> + __le16 tlp_setting;
> + __le16 rsvd1;
> + __le16 cid;
> + __le32 byte_cnt;
> + __le32 addr_lo; /* SADDR_LO/WIADDR_LO */
> + __le32 addr_hi; /* SADDR_HI/WIADDR_HI */
> + __le32 daddr_lo;
> + __le32 daddr_hi;
> + __le16 dfid;
> + __le16 sfid;
> +};
> +
> +#define SWITCHTEC_SE_DFM BIT(5)
> +#define SWITCHTEC_SE_LIOF BIT(6)
> +#define SWITCHTEC_SE_BRR BIT(7)
> +#define SWITCHTEC_SE_CID_MASK GENMASK(15, 0)
> +
> +#define SWITCHTEC_CE_SC_LEN_ERR BIT(0)
> +#define SWITCHTEC_CE_SC_UR BIT(1)
> +#define SWITCHTEC_CE_SC_CA BIT(2)
> +#define SWITCHTEC_CE_SC_RSVD_CPL BIT(3)
> +#define SWITCHTEC_CE_SC_ECRC_ERR BIT(4)
> +#define SWITCHTEC_CE_SC_EP_SET BIT(5)
> +#define SWITCHTEC_CE_SC_D_RD_CTO BIT(8)
> +#define SWITCHTEC_CE_SC_D_RIMM_UR BIT(9)
> +#define SWITCHTEC_CE_SC_D_RIMM_CA BIT(10)
> +#define SWITCHTEC_CE_SC_D_RIMM_RSVD_CPL BIT(11)
> +#define SWITCHTEC_CE_SC_D_ECRC BIT(12)
> +#define SWITCHTEC_CE_SC_D_EP_SET BIT(13)
> +#define SWITCHTEC_CE_SC_D_BAD_CONNID BIT(14)
> +#define SWITCHTEC_CE_SC_D_BAD_RHI_ADDR BIT(15)
> +#define SWITCHTEC_CE_SC_D_INVD_CMD BIT(16)
> +#define SWITCHTEC_CE_SC_MASK GENMASK(16, 0)
> +
> +struct switchtec_dma_hw_ce {
> + __le32 rdimm_cpl_dw0;
> + __le32 rdimm_cpl_dw1;
> + __le32 rsvd1;
> + __le32 cpl_byte_cnt;
> + __le16 sq_head;
> + __le16 rsvd2;
> + __le32 rsvd3;
> + __le32 sts_code;
> + __le16 cid;
> + __le16 phase_tag;
> +};
> +
> +struct switchtec_dma_desc {
> + struct dma_async_tx_descriptor txd;
> + struct switchtec_dma_hw_se_desc *hw;
> + u32 orig_size;
> + bool completed;
> +};
> +
> +#define SWITCHTEC_INVALID_HFID 0xffff
> +
> +#define SWITCHTEC_DMA_SQ_SIZE SZ_32K
> +#define SWITCHTEC_DMA_CQ_SIZE SZ_32K
> +
> +#define SWITCHTEC_DMA_RING_SIZE SWITCHTEC_DMA_SQ_SIZE
> +
> +static int
> +wait_for_chan_status(struct chan_hw_regs __iomem *chan_hw, u32 mask, bool set)
> +{
> + u32 status;
> + int ret;
> +
> + ret = readl_poll_timeout_atomic(&chan_hw->status, status,
> + (set && (status & mask)) ||
> + (!set && !(status & mask)),
> + 10, 100 * USEC_PER_MSEC);
> + if (ret)
> + return -EIO;
it can be timeout too, doesnt it make sense to propagate that?
> +
> + return 0;
> +}
> +
> +static int halt_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> + int ret;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + ret = -ENODEV;
> + goto unlock_and_exit;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + writeb(SWITCHTEC_CHAN_CTRL_HALT, &chan_hw->ctrl);
> + ret = wait_for_chan_status(chan_hw, SWITCHTEC_CHAN_STS_HALTED, true);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> +
> +unlock_and_exit:
> + rcu_read_unlock();
> + return ret;
> +}
> +
> +static int unhalt_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + u8 ctrl;
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> + int ret;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + ret = -ENODEV;
> + goto unlock_and_exit;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + ctrl = readb(&chan_hw->ctrl);
> + ctrl &= ~SWITCHTEC_CHAN_CTRL_HALT;
> + writeb(ctrl, &chan_hw->ctrl);
> + ret = wait_for_chan_status(chan_hw, SWITCHTEC_CHAN_STS_HALTED, false);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> +
> +unlock_and_exit:
> + rcu_read_unlock();
> + return ret;
> +}
> +
> +static void flush_pci_write(struct chan_hw_regs __iomem *chan_hw)
> +{
> + readl(&chan_hw->cq_head);
> +}
> +
> +static int reset_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + rcu_read_unlock();
> + return -ENODEV;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + writel(SWITCHTEC_CHAN_CTRL_RESET | SWITCHTEC_CHAN_CTRL_ERR_PAUSE,
> + &chan_hw->ctrl);
> + flush_pci_write(chan_hw);
> +
> + udelay(1000);
> +
> + writel(SWITCHTEC_CHAN_CTRL_ERR_PAUSE, &chan_hw->ctrl);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> + flush_pci_write(chan_hw);
> +
> + rcu_read_unlock();
> + return 0;
> +}
> +
> +static int pause_reset_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + rcu_read_unlock();
> + return -ENODEV;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + writeb(SWITCHTEC_CHAN_CTRL_PAUSE, &chan_hw->ctrl);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> +
> + flush_pci_write(chan_hw);
> +
> + rcu_read_unlock();
> +
> + /* wait 60ms to ensure no pending CEs */
> + mdelay(60);
> +
> + return reset_channel(swdma_chan);
> +}
> +
> +static int switchtec_dma_pause(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> + int ret;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + ret = -ENODEV;
> + goto unlock_and_exit;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + writeb(SWITCHTEC_CHAN_CTRL_PAUSE, &chan_hw->ctrl);
> + ret = wait_for_chan_status(chan_hw, SWITCHTEC_CHAN_STS_PAUSED, true);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> +
> +unlock_and_exit:
> + rcu_read_unlock();
> + return ret;
> +}
> +
> +static int switchtec_dma_resume(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + struct chan_hw_regs __iomem *chan_hw = swdma_chan->mmio_chan_hw;
> + struct pci_dev *pdev;
> + int ret;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + ret = -ENODEV;
> + goto unlock_and_exit;
> + }
> +
> + spin_lock(&swdma_chan->hw_ctrl_lock);
> + writeb(0, &chan_hw->ctrl);
> + ret = wait_for_chan_status(chan_hw, SWITCHTEC_CHAN_STS_PAUSED, false);
> + spin_unlock(&swdma_chan->hw_ctrl_lock);
> +
> +unlock_and_exit:
> + rcu_read_unlock();
> + return ret;
> +}
> +
> +enum chan_op {
> + ENABLE_CHAN,
> + DISABLE_CHAN,
> +};
> +
> +static int channel_op(struct switchtec_dma_chan *swdma_chan, int op)
> +{
> + struct chan_fw_regs __iomem *chan_fw = swdma_chan->mmio_chan_fw;
> + struct pci_dev *pdev;
> + u32 valid_en_se;
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> + if (!pdev) {
> + rcu_read_unlock();
> + return -ENODEV;
> + }
> +
> + valid_en_se = readl(&chan_fw->valid_en_se);
> + if (op == ENABLE_CHAN)
> + valid_en_se |= SWITCHTEC_CHAN_ENABLE;
> + else
> + valid_en_se &= ~SWITCHTEC_CHAN_ENABLE;
> +
> + writel(valid_en_se, &chan_fw->valid_en_se);
> +
> + rcu_read_unlock();
> + return 0;
> +}
> +
> +static int enable_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + return channel_op(swdma_chan, ENABLE_CHAN);
> +}
> +
> +static int disable_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + return channel_op(swdma_chan, DISABLE_CHAN);
> +}
> +
> +static struct switchtec_dma_desc *
> +switchtec_dma_get_desc(struct switchtec_dma_chan *swdma_chan, int i)
> +{
> + return swdma_chan->desc_ring[i];
> +}
> +
> +static struct switchtec_dma_hw_ce *
> +switchtec_dma_get_ce(struct switchtec_dma_chan *swdma_chan, int i)
> +{
> + return &swdma_chan->hw_cq[i];
> +}
> +
> +static void switchtec_dma_process_desc(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct device *chan_dev = to_chan_dev(swdma_chan);
> + struct dmaengine_result res;
> + struct switchtec_dma_desc *desc;
> + struct switchtec_dma_hw_ce *ce;
> + __le16 phase_tag;
> + int tail;
> + int cid;
> + int se_idx;
> + u32 sts_code;
> + int i;
> + __le32 *p;
> +
> + do {
> + spin_lock_bh(&swdma_chan->complete_lock);
> + if (!swdma_chan->comp_ring_active) {
> + spin_unlock_bh(&swdma_chan->complete_lock);
> + break;
> + }
> +
> + ce = switchtec_dma_get_ce(swdma_chan, swdma_chan->cq_tail);
> +
> + /*
> + * phase_tag is updated by hardware, ensure the value is
> + * not from the cache
> + */
> + phase_tag = smp_load_acquire(&ce->phase_tag);
> + if (le16_to_cpu(phase_tag) == swdma_chan->phase_tag) {
> + spin_unlock_bh(&swdma_chan->complete_lock);
> + break;
> + }
> +
> + cid = le16_to_cpu(ce->cid);
> + se_idx = cid & (SWITCHTEC_DMA_SQ_SIZE - 1);
> + desc = switchtec_dma_get_desc(swdma_chan, se_idx);
> +
> + tail = swdma_chan->tail;
> +
> + res.residue = desc->orig_size - le32_to_cpu(ce->cpl_byte_cnt);
> +
> + sts_code = le32_to_cpu(ce->sts_code);
> +
> + if (!(sts_code & SWITCHTEC_CE_SC_MASK)) {
> + res.result = DMA_TRANS_NOERROR;
> + } else {
> + if (sts_code & SWITCHTEC_CE_SC_D_RD_CTO)
> + res.result = DMA_TRANS_READ_FAILED;
> + else
> + res.result = DMA_TRANS_WRITE_FAILED;
> +
> + dev_err(chan_dev, "CID 0x%04x failed, SC 0x%08x\n", cid,
> + (u32)(sts_code & SWITCHTEC_CE_SC_MASK));
> +
> + p = (__le32 *)ce;
> + for (i = 0; i < sizeof(*ce) / 4; i++) {
> + dev_err(chan_dev, "CE DW%d: 0x%08x\n", i,
> + le32_to_cpu(*p));
> + p++;
> + }
> + }
> +
> + desc->completed = true;
> +
> + swdma_chan->cq_tail++;
> + swdma_chan->cq_tail &= SWITCHTEC_DMA_CQ_SIZE - 1;
> +
> + rcu_read_lock();
> + if (!rcu_dereference(swdma_chan->swdma_dev->pdev)) {
> + rcu_read_unlock();
> + spin_unlock_bh(&swdma_chan->complete_lock);
> + return;
> + }
> + writew(swdma_chan->cq_tail, &swdma_chan->mmio_chan_hw->cq_head);
> + rcu_read_unlock();
> +
> + if (swdma_chan->cq_tail == 0)
> + swdma_chan->phase_tag = !swdma_chan->phase_tag;
> +
> + /* Out of order CE */
> + if (se_idx != tail) {
> + spin_unlock_bh(&swdma_chan->complete_lock);
> + continue;
> + }
> +
> + do {
> + dma_cookie_complete(&desc->txd);
> + dma_descriptor_unmap(&desc->txd);
> + dmaengine_desc_get_callback_invoke(&desc->txd, &res);
> + desc->txd.callback = NULL;
> + desc->txd.callback_result = NULL;
> + desc->completed = false;
> +
> + tail++;
> + tail &= SWITCHTEC_DMA_SQ_SIZE - 1;
> +
> + /*
> + * Ensure the desc updates are visible before updating
> + * the tail index
> + */
> + smp_store_release(&swdma_chan->tail, tail);
> + desc = switchtec_dma_get_desc(swdma_chan,
> + swdma_chan->tail);
> + if (!desc->completed)
> + break;
> + } while (CIRC_CNT(READ_ONCE(swdma_chan->head), swdma_chan->tail,
> + SWITCHTEC_DMA_SQ_SIZE));
> +
> + spin_unlock_bh(&swdma_chan->complete_lock);
> + } while (1);
> +}
> +
> +static void
> +switchtec_dma_abort_desc(struct switchtec_dma_chan *swdma_chan, int force)
> +{
> + struct dmaengine_result res;
> + struct switchtec_dma_desc *desc;
> +
> + if (!force)
> + switchtec_dma_process_desc(swdma_chan);
> +
> + spin_lock_bh(&swdma_chan->complete_lock);
> +
> + while (CIRC_CNT(swdma_chan->head, swdma_chan->tail,
> + SWITCHTEC_DMA_SQ_SIZE) >= 1) {
> + desc = switchtec_dma_get_desc(swdma_chan, swdma_chan->tail);
> +
> + res.residue = desc->orig_size;
> + res.result = DMA_TRANS_ABORTED;
> +
> + dma_cookie_complete(&desc->txd);
> + dma_descriptor_unmap(&desc->txd);
> + if (!force)
> + dmaengine_desc_get_callback_invoke(&desc->txd, &res);
> + desc->txd.callback = NULL;
> + desc->txd.callback_result = NULL;
> +
> + swdma_chan->tail++;
> + swdma_chan->tail &= SWITCHTEC_DMA_SQ_SIZE - 1;
> + }
> +
> + spin_unlock_bh(&swdma_chan->complete_lock);
> +}
> +
> +static void switchtec_dma_chan_stop(struct switchtec_dma_chan *swdma_chan)
> +{
> + int rc;
> +
> + rc = halt_channel(swdma_chan);
> + if (rc)
> + return;
> +
> + rcu_read_lock();
> + if (!rcu_dereference(swdma_chan->swdma_dev->pdev)) {
> + rcu_read_unlock();
> + return;
> + }
> +
> + writel(0, &swdma_chan->mmio_chan_fw->sq_base_lo);
> + writel(0, &swdma_chan->mmio_chan_fw->sq_base_hi);
> + writel(0, &swdma_chan->mmio_chan_fw->cq_base_lo);
> + writel(0, &swdma_chan->mmio_chan_fw->cq_base_hi);
> +
> + rcu_read_unlock();
> +}
> +
> +static int switchtec_dma_terminate_all(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> +
> + spin_lock_bh(&swdma_chan->complete_lock);
> + swdma_chan->comp_ring_active = false;
> + spin_unlock_bh(&swdma_chan->complete_lock);
> +
> + return pause_reset_channel(swdma_chan);
> +}
> +
> +static void switchtec_dma_synchronize(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + int rc;
> +
> + switchtec_dma_abort_desc(swdma_chan, 1);
> +
> + rc = enable_channel(swdma_chan);
> + if (rc)
> + return;
> +
> + rc = reset_channel(swdma_chan);
> + if (rc)
> + return;
> +
> + rc = unhalt_channel(swdma_chan);
> + if (rc)
> + return;
> +
> + spin_lock_bh(&swdma_chan->submit_lock);
> + swdma_chan->head = 0;
> + spin_unlock_bh(&swdma_chan->submit_lock);
> +
> + spin_lock_bh(&swdma_chan->complete_lock);
> + swdma_chan->comp_ring_active = true;
> + swdma_chan->phase_tag = 0;
> + swdma_chan->tail = 0;
> + swdma_chan->cq_tail = 0;
> + swdma_chan->cid = 0;
> + dma_cookie_init(chan);
> + spin_unlock_bh(&swdma_chan->complete_lock);
> +}
> +
> +static void switchtec_dma_desc_task(unsigned long data)
> +{
> + struct switchtec_dma_chan *swdma_chan = (void *)data;
> +
> + switchtec_dma_process_desc(swdma_chan);
> +}
> +
> +static void switchtec_dma_chan_status_task(unsigned long data)
> +{
> + struct switchtec_dma_dev *swdma_dev = (void *)data;
> + struct dma_device *dma_dev = &swdma_dev->dma_dev;
> + struct switchtec_dma_chan *swdma_chan;
> + struct chan_hw_regs __iomem *chan_hw;
> + struct dma_chan *chan;
> + struct device *chan_dev;
> + u32 chan_status;
> + int bit;
> +
> + list_for_each_entry(chan, &dma_dev->channels, device_node) {
> + swdma_chan = to_switchtec_dma_chan(chan);
> + chan_dev = to_chan_dev(swdma_chan);
> + chan_hw = swdma_chan->mmio_chan_hw;
> +
> + rcu_read_lock();
> + if (!rcu_dereference(swdma_dev->pdev)) {
> + rcu_read_unlock();
> + return;
> + }
> +
> + chan_status = readl(&chan_hw->status);
> + chan_status &= SWITCHTEC_CHAN_STS_PAUSED_MASK;
> + rcu_read_unlock();
> +
> + bit = ffs(chan_status);
> + if (!bit)
> + dev_dbg(chan_dev, "No pause bit set.");
> + else
> + dev_err(chan_dev, "Paused, %s\n",
> + channel_status_str[bit - 1]);
> + }
> +}
> +
> +static struct dma_async_tx_descriptor *
> +switchtec_dma_prep_desc(struct dma_chan *c, u16 dst_fid, dma_addr_t dma_dst,
> + u16 src_fid, dma_addr_t dma_src, u64 data,
> + size_t len, unsigned long flags)
> + __acquires(swdma_chan->submit_lock)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(c);
> + struct switchtec_dma_desc *desc;
> + int head;
> + int tail;
> +
> + spin_lock_bh(&swdma_chan->submit_lock);
> +
> + if (!swdma_chan->ring_active)
> + goto err_unlock;
> +
> + tail = READ_ONCE(swdma_chan->tail);
> + head = swdma_chan->head;
> +
> + if (!CIRC_SPACE(head, tail, SWITCHTEC_DMA_RING_SIZE))
> + goto err_unlock;
> +
> + desc = switchtec_dma_get_desc(swdma_chan, head);
> +
> + if (src_fid != SWITCHTEC_INVALID_HFID &&
> + dst_fid != SWITCHTEC_INVALID_HFID)
> + desc->hw->ctrl |= SWITCHTEC_SE_DFM;
> +
> + if (flags & DMA_PREP_INTERRUPT)
> + desc->hw->ctrl |= SWITCHTEC_SE_LIOF;
> +
> + if (flags & DMA_PREP_FENCE)
> + desc->hw->ctrl |= SWITCHTEC_SE_BRR;
> +
> + desc->txd.flags = flags;
> +
> + desc->completed = false;
> + desc->hw->opc = SWITCHTEC_DMA_OPC_MEMCPY;
> + desc->hw->addr_lo = cpu_to_le32(lower_32_bits(dma_src));
> + desc->hw->addr_hi = cpu_to_le32(upper_32_bits(dma_src));
> + desc->hw->daddr_lo = cpu_to_le32(lower_32_bits(dma_dst));
> + desc->hw->daddr_hi = cpu_to_le32(upper_32_bits(dma_dst));
> + desc->hw->byte_cnt = cpu_to_le32(len);
> + desc->hw->tlp_setting = 0;
> + desc->hw->dfid = cpu_to_le16(dst_fid);
> + desc->hw->sfid = cpu_to_le16(src_fid);
> + swdma_chan->cid &= SWITCHTEC_SE_CID_MASK;
> + desc->hw->cid = cpu_to_le16(swdma_chan->cid++);
> + desc->orig_size = len;
> +
> + head++;
> + head &= SWITCHTEC_DMA_RING_SIZE - 1;
> +
> + /*
> + * Ensure the desc updates are visible before updating the head index
> + */
> + smp_store_release(&swdma_chan->head, head);
> +
> + /* return with the lock held, it will be released in tx_submit */
> +
> + return &desc->txd;
> +
> +err_unlock:
> + /*
> + * Keep sparse happy by restoring an even lock count on
> + * this lock.
> + */
> + __acquire(swdma_chan->submit_lock);
> +
> + spin_unlock_bh(&swdma_chan->submit_lock);
> + return NULL;
> +}
> +
> +static struct dma_async_tx_descriptor *
> +switchtec_dma_prep_memcpy(struct dma_chan *c, dma_addr_t dma_dst,
> + dma_addr_t dma_src, size_t len, unsigned long flags)
> + __acquires(swdma_chan->submit_lock)
> +{
> + if (len > SWITCHTEC_DESC_MAX_SIZE) {
> + /*
> + * Keep sparse happy by restoring an even lock count on
> + * this lock.
> + */
> + __acquire(swdma_chan->submit_lock);
> + return NULL;
> + }
> +
> + return switchtec_dma_prep_desc(c, SWITCHTEC_INVALID_HFID, dma_dst,
> + SWITCHTEC_INVALID_HFID, dma_src, 0, len,
> + flags);
> +}
> +
> +static dma_cookie_t
> +switchtec_dma_tx_submit(struct dma_async_tx_descriptor *desc)
> + __releases(swdma_chan->submit_lock)
> +{
> + struct switchtec_dma_chan *swdma_chan =
> + to_switchtec_dma_chan(desc->chan);
> + dma_cookie_t cookie;
> +
> + cookie = dma_cookie_assign(desc);
> +
> + spin_unlock_bh(&swdma_chan->submit_lock);
I was expecting desc to be pushing to pending list?? where is that done
Also consider using virt-dma for desc management, you dont need to
handle that on your own
> +
> + return cookie;
> +}
> +
> +static enum dma_status switchtec_dma_tx_status(struct dma_chan *chan,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + enum dma_status ret;
> +
> + ret = dma_cookie_status(chan, cookie, txstate);
> + if (ret == DMA_COMPLETE)
> + return ret;
> +
> + switchtec_dma_process_desc(swdma_chan);
This is *wrong*, you cannot process desc in status API, Please read the
documentation again and if in doubt pls ask
--
~Vinod
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