On 18-05-23, 09:59, 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.
>
> Signed-off-by: Kelvin Cao <kelvin.cao@xxxxxxxxxxxxx>
> Co-developed-by: George Ge <george.ge@xxxxxxxxxxxxx>
> Signed-off-by: George Ge <george.ge@xxxxxxxxxxxxx>
> ---
> MAINTAINERS | 6 +
> drivers/dma/Kconfig | 9 +
> drivers/dma/Makefile | 1 +
> drivers/dma/switchtec_dma.c | 1570 +++++++++++++++++++++++++++++++++++
> 4 files changed, 1586 insertions(+)
> create mode 100644 drivers/dma/switchtec_dma.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e0ad886d3163..24e8d4463592 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20346,6 +20346,12 @@ S: Supported
> F: include/net/switchdev.h
> F: net/switchdev/
>
> +SWITCHTEC DMA DRIVER
> +M: Kelvin Cao <kelvin.cao@xxxxxxxxxxxxx>
> +L: dmaengine@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/dma/switchtec_dma.c
> +
> SY8106A REGULATOR DRIVER
> M: Icenowy Zheng <icenowy@xxxxxxx>
> S: Maintained
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index f5f422f9b850..cfc8b1988a3b 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -610,6 +610,15 @@ 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 a4fd1ce29510..977c97cda53d 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -70,6 +70,7 @@ 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..2df6ad5c3ce6
> --- /dev/null
> +++ b/drivers/dma/switchtec_dma.c
> @@ -0,0 +1,1570 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Microchip Switchtec(tm) DMA Controller Driver
> + * Copyright (c) 2023, Kelvin Cao <kelvin.cao@xxxxxxxxxxxxx>
> + * Copyright (c) 2023, Microchip Corporation
> + */
> +
> +#include <linux/circ_buf.h>
> +#include <linux/dmaengine.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/delay.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,
> +};
> +
> +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,
> +};
> +
> +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,
> +};
> +
> +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;
> + spinlock_t hw_ctrl_lock;
> +
> + struct tasklet_struct desc_task;
> + spinlock_t submit_lock;
> + bool ring_active;
> + int cid;
> + 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
> +
> +enum desc_type {
> + MEMCPY,
> + WIMM,
> + UNKNOWN_TRANSACTION,
> +};
> +
> +#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)
single line would read much better! (here and few other places)
Also run checkpatch with --strict option, that will help catch style
inconsistencies (i am seeing some below)
> +{
> + u32 status;
> + int retry = 100;
> + int ret = -EIO;
> +
> + do {
> + status = readl(&chan_hw->status);
> + if ((set && (status & mask)) ||
> + (!set && !(status & mask))) {
> + ret = 0;
> + break;
> + }
why not use readl_poll_timeout()
> +
> + udelay(1000);
> + } while (retry--);
> +
> + return ret;
> +}
> +
> +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);
> +
drop the empty line here
> +}
> +
> +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;
> +}
> +
> +static int enable_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + u32 valid_en_se;
> + struct chan_fw_regs __iomem *chan_fw = swdma_chan->mmio_chan_fw;
> + struct pci_dev *pdev;
reverse christmas tree pls
> +
> + 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);
> + valid_en_se |= SWITCHTEC_CHAN_ENABLE;
> +
> + writel(valid_en_se, &chan_fw->valid_en_se);
> +
> + rcu_read_unlock();
> + return 0;
> +}
> +
> +static int disable_channel(struct switchtec_dma_chan *swdma_chan)
> +{
> + u32 valid_en_se;
> + struct chan_fw_regs __iomem *chan_fw = swdma_chan->mmio_chan_fw;
> + struct pci_dev *pdev;
> +
> + 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);
> + valid_en_se &= ~SWITCHTEC_CHAN_ENABLE;
> +
> + writel(valid_en_se, &chan_fw->valid_en_se);
> +
> + rcu_read_unlock();
> + return 0;
only diff b/w enable/disable is bit ops, I guess we can have a common fn
with argument for enable/disable
> +}
> +
> +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 dma_chan *chan;
> + struct switchtec_dma_chan *swdma_chan;
> + struct chan_hw_regs __iomem *chan_hw;
> + 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, enum desc_type type, 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;
> +
> +
> + if (type != MEMCPY && type != WIMM) {
> + /*
> + * Keep sparse happy by restoring an even lock count on
> + * this lock.
> + */
> + __acquire(swdma_chan->submit_lock);
> + return NULL;
> + }
> +
> + 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;
> + if (type == MEMCPY) {
> + 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));
> + } else {
> + desc->hw->opc = SWITCHTEC_DMA_OPC_WRIMM;
> + desc->hw->addr_lo = cpu_to_le32(lower_32_bits(data));
> + desc->hw->addr_hi = cpu_to_le32(upper_32_bits(data));
> + }
> + 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, MEMCPY, SWITCHTEC_INVALID_HFID,
> + dma_dst, SWITCHTEC_INVALID_HFID, dma_src,
> + 0, len, flags);
> +}
> +
> +static struct dma_async_tx_descriptor *switchtec_dma_prep_wimm_data(
> + struct dma_chan *c, dma_addr_t dma_dst, u64 data,
> + unsigned long flags)
> + __acquires(swdma_chan->submit_lock)
> +{
can you please explain what is meant by wimm data and how it us used?
> + size_t len = sizeof(data);
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(c);
> + struct device *chan_dev = to_chan_dev(swdma_chan);
> +
> + if ((len == 8) && (dma_dst & ((1 << DMAENGINE_ALIGN_8_BYTES) - 1))) {
> + dev_err(chan_dev,
> + "QW WIMM dst addr 0x%08x_%08x not QW aligned!\n",
> + upper_32_bits(dma_dst), lower_32_bits(dma_dst));
> + /*
> + * 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, WIMM, SWITCHTEC_INVALID_HFID, dma_dst,
> + SWITCHTEC_INVALID_HFID, 0, data, 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 dont this is correct, why would you prevent users from preparing
multiple descriptors..?
> +
> + 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);
> +
> + return dma_cookie_status(chan, cookie, txstate);
> +}
> +
> +static void switchtec_dma_issue_pending(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + struct switchtec_dma_dev *swdma_dev = swdma_chan->swdma_dev;
> +
> + /*
> + * Ensure the desc updates are visible before starting the
> + * DMA engine.
> + */
> + wmb();
> +
> + /*
> + * The sq_tail register is actually for the head of the
> + * submisssion queue. Chip has the opposite define of head/tail
> + * to the Linux kernel.
> + */
> +
> + rcu_read_lock();
> + if (!rcu_dereference(swdma_dev->pdev)) {
> + rcu_read_unlock();
> + return;
> + }
> +
> + spin_lock_bh(&swdma_chan->submit_lock);
> + writew(swdma_chan->head, &swdma_chan->mmio_chan_hw->sq_tail);
> + spin_unlock_bh(&swdma_chan->submit_lock);
> +
> + rcu_read_unlock();
> +}
> +
> +static irqreturn_t switchtec_dma_isr(int irq, void *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = chan;
> +
> + if (swdma_chan->comp_ring_active)
> + tasklet_schedule(&swdma_chan->desc_task);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t switchtec_dma_chan_status_isr(int irq, void *dma)
> +{
> + struct switchtec_dma_dev *swdma_dev = dma;
> +
> + tasklet_schedule(&swdma_dev->chan_status_task);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void switchtec_dma_free_desc(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct switchtec_dma_dev *swdma_dev = swdma_chan->swdma_dev;
> + size_t size;
> + int i;
> +
> + size = SWITCHTEC_DMA_SQ_SIZE * sizeof(*swdma_chan->hw_sq);
> + if (swdma_chan->hw_sq)
> + dma_free_coherent(swdma_dev->dma_dev.dev, size,
> + swdma_chan->hw_sq, swdma_chan->dma_addr_sq);
> +
> + size = SWITCHTEC_DMA_CQ_SIZE * sizeof(*swdma_chan->hw_cq);
> + if (swdma_chan->hw_cq)
> + dma_free_coherent(swdma_dev->dma_dev.dev, size,
> + swdma_chan->hw_cq, swdma_chan->dma_addr_cq);
> +
> + if (swdma_chan->desc_ring) {
> + for (i = 0; i < SWITCHTEC_DMA_RING_SIZE; i++)
> + kfree(swdma_chan->desc_ring[i]);
> +
> + kfree(swdma_chan->desc_ring);
> + }
> +}
> +
> +static int switchtec_dma_alloc_desc(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct switchtec_dma_dev *swdma_dev = swdma_chan->swdma_dev;
> + struct pci_dev *pdev;
> + struct chan_fw_regs __iomem *chan_fw = swdma_chan->mmio_chan_fw;
> + size_t size;
> + struct switchtec_dma_desc *desc;
> + int rc;
> + int i;
> +
> + swdma_chan->head = swdma_chan->tail = 0;
> + swdma_chan->cq_tail = 0;
> +
> + size = SWITCHTEC_DMA_SQ_SIZE * sizeof(*swdma_chan->hw_sq);
> + swdma_chan->hw_sq = dma_alloc_coherent(swdma_dev->dma_dev.dev, size,
> + &swdma_chan->dma_addr_sq,
> + GFP_KERNEL);
this can be called from atomic context, GFP_NOWAIT pls
> + if (!swdma_chan->hw_sq) {
> + rc = -ENOMEM;
> + goto free_and_exit;
> + }
> +
> + size = SWITCHTEC_DMA_CQ_SIZE * sizeof(*swdma_chan->hw_cq);
> + swdma_chan->hw_cq = dma_alloc_coherent(swdma_dev->dma_dev.dev, size,
> + &swdma_chan->dma_addr_cq,
> + GFP_KERNEL);
> + if (!swdma_chan->hw_cq) {
> + rc = -ENOMEM;
> + goto free_and_exit;
> + }
> +
> + /* reset host phase tag */
> + swdma_chan->phase_tag = 0;
> +
> + size = sizeof(*swdma_chan->desc_ring);
> + swdma_chan->desc_ring = kcalloc(SWITCHTEC_DMA_RING_SIZE, size,
> + GFP_KERNEL);
> + if (!swdma_chan->desc_ring) {
> + rc = -ENOMEM;
> + goto free_and_exit;
> + }
> +
> + for (i = 0; i < SWITCHTEC_DMA_RING_SIZE; i++) {
> + desc = kzalloc(sizeof(*desc), GFP_KERNEL);
> + if (!desc) {
> + rc = -ENOMEM;
> + goto free_and_exit;
> + }
> +
> + dma_async_tx_descriptor_init(&desc->txd, &swdma_chan->dma_chan);
> + desc->txd.tx_submit = switchtec_dma_tx_submit;
> + desc->hw = &swdma_chan->hw_sq[i];
> + desc->completed = true;
> +
> + swdma_chan->desc_ring[i] = desc;
> + }
> +
> + rcu_read_lock();
> + pdev = rcu_dereference(swdma_dev->pdev);
> + if (!pdev) {
> + rcu_read_unlock();
> + rc = -ENODEV;
> + goto free_and_exit;
> + }
> +
> + /* set sq/cq */
> + writel(lower_32_bits(swdma_chan->dma_addr_sq), &chan_fw->sq_base_lo);
> + writel(upper_32_bits(swdma_chan->dma_addr_sq), &chan_fw->sq_base_hi);
> + writel(lower_32_bits(swdma_chan->dma_addr_cq), &chan_fw->cq_base_lo);
> + writel(upper_32_bits(swdma_chan->dma_addr_cq), &chan_fw->cq_base_hi);
> +
> + writew(SWITCHTEC_DMA_SQ_SIZE, &swdma_chan->mmio_chan_fw->sq_size);
> + writew(SWITCHTEC_DMA_CQ_SIZE, &swdma_chan->mmio_chan_fw->cq_size);
why is hardware being written in alloc call, the job is to prepare
descritor, hw write should happen when we submit the descriptors..
> +
> + rcu_read_unlock();
> + return 0;
> +
> +free_and_exit:
> + switchtec_dma_free_desc(swdma_chan);
> + return rc;
> +}
> +
> +static int switchtec_dma_alloc_chan_resources(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> + struct switchtec_dma_dev *swdma_dev = swdma_chan->swdma_dev;
> + u32 perf_cfg;
> + int rc;
> +
> + rc = switchtec_dma_alloc_desc(swdma_chan);
> + if (rc)
> + return rc;
> +
> + rc = enable_channel(swdma_chan);
> + if (rc)
> + return rc;
> +
> + rc = reset_channel(swdma_chan);
> + if (rc)
> + return rc;
> +
> + rc = unhalt_channel(swdma_chan);
> + if (rc)
> + return rc;
> +
> + swdma_chan->ring_active = true;
> + swdma_chan->comp_ring_active = true;
> + swdma_chan->cid = 0;
> +
> + dma_cookie_init(chan);
> +
> + rcu_read_lock();
> + if (!rcu_dereference(swdma_dev->pdev)) {
> + rcu_read_unlock();
> + return -ENODEV;
> + }
> +
> + perf_cfg = readl(&swdma_chan->mmio_chan_fw->perf_cfg);
> + rcu_read_unlock();
> +
> + dev_dbg(&chan->dev->device, "Burst Size: 0x%x",
> + (perf_cfg >> PERF_BURST_SIZE_SHIFT) & PERF_BURST_SIZE_MASK);
> +
> + dev_dbg(&chan->dev->device, "Burst Scale: 0x%x",
> + (perf_cfg >> PERF_BURST_SCALE_SHIFT) & PERF_BURST_SCALE_MASK);
> +
> + dev_dbg(&chan->dev->device, "Interval: 0x%x",
> + (perf_cfg >> PERF_INTERVAL_SHIFT) & PERF_INTERVAL_MASK);
> +
> + dev_dbg(&chan->dev->device, "Arb Weight: 0x%x",
> + (perf_cfg >> PERF_ARB_WEIGHT_SHIFT) & PERF_ARB_WEIGHT_MASK);
> +
> + dev_dbg(&chan->dev->device, "MRRS: 0x%x",
> + (perf_cfg >> PERF_MRRS_SHIFT) & PERF_MRRS_MASK);
> +
> + return SWITCHTEC_DMA_SQ_SIZE;
> +}
> +
> +static void switchtec_dma_free_chan_resources(struct dma_chan *chan)
> +{
> + struct switchtec_dma_chan *swdma_chan = to_switchtec_dma_chan(chan);
> +
> + spin_lock_bh(&swdma_chan->submit_lock);
> + swdma_chan->ring_active = false;
> + spin_unlock_bh(&swdma_chan->submit_lock);
> +
> + spin_lock_bh(&swdma_chan->complete_lock);
> + swdma_chan->comp_ring_active = false;
> + spin_unlock_bh(&swdma_chan->complete_lock);
> +
> + switchtec_dma_chan_stop(swdma_chan);
> +
> + tasklet_kill(&swdma_chan->desc_task);
> +
> + switchtec_dma_abort_desc(swdma_chan, 0);
> +
> + switchtec_dma_free_desc(swdma_chan);
> +
> + disable_channel(swdma_chan);
> +}
> +
> +static int switchtec_dma_chan_init(struct switchtec_dma_dev *swdma_dev, int i)
> +{
> + struct dma_device *dma = &swdma_dev->dma_dev;
> + struct pci_dev *pdev = rcu_dereference(swdma_dev->pdev);
> + struct dma_chan *chan;
> + struct switchtec_dma_chan *swdma_chan;
> + u32 perf_cfg;
> + u32 valid_en_se;
> + u32 thresh;
> + int se_buf_len;
> + int irq;
> + int rc;
> +
> + swdma_chan = kzalloc(sizeof(*swdma_chan), GFP_KERNEL);
> + if (!swdma_chan)
> + return -ENOMEM;
> +
> + swdma_chan->phase_tag = 0;
> + swdma_chan->index = i;
> + swdma_chan->swdma_dev = swdma_dev;
> +
> + swdma_chan->mmio_chan_fw =
> + swdma_dev->bar + SWITCHTEC_DMAC_CHAN_CFG_STS_OFFSET +
> + i * SWITCHTEC_DMA_CHAN_FW_REGS_SIZE;
> + swdma_chan->mmio_chan_hw =
> + swdma_dev->bar + SWITCHTEC_DMAC_CHAN_CTRL_OFFSET +
> + i * SWITCHTEC_DMA_CHAN_HW_REGS_SIZE;
> +
> + swdma_dev->swdma_chans[i] = swdma_chan;
> +
> + rc = pause_reset_channel(swdma_chan);
> + if (rc)
> + goto free_and_exit;
> +
> + perf_cfg = readl(&swdma_chan->mmio_chan_fw->perf_cfg);
> +
> + /* init perf tuner */
> + perf_cfg = PERF_BURST_SCALE << PERF_BURST_SCALE_SHIFT;
> + perf_cfg |= PERF_MRRS << PERF_MRRS_SHIFT;
> + perf_cfg |= PERF_INTERVAL << PERF_INTERVAL_SHIFT;
> + perf_cfg |= PERF_BURST_SIZE << PERF_BURST_SIZE_SHIFT;
> + perf_cfg |= PERF_ARB_WEIGHT << PERF_ARB_WEIGHT_SHIFT;
> +
> + writel(perf_cfg, &swdma_chan->mmio_chan_fw->perf_cfg);
> +
> + valid_en_se = readl(&swdma_chan->mmio_chan_fw->valid_en_se);
> +
> + dev_dbg(&pdev->dev, "Channel %d: SE buffer base %d\n",
> + i, (valid_en_se >> SE_BUF_BASE_SHIFT) & SE_BUF_BASE_MASK);
> +
> + se_buf_len = (valid_en_se >> SE_BUF_LEN_SHIFT) & SE_BUF_LEN_MASK;
> + dev_dbg(&pdev->dev, "Channel %d: SE buffer count %d\n", i, se_buf_len);
> +
> + thresh = se_buf_len / 2;
> + valid_en_se |= (thresh & SE_THRESH_MASK) << SE_THRESH_SHIFT;
> + writel(valid_en_se, &swdma_chan->mmio_chan_fw->valid_en_se);
> +
> + /* request irqs */
> + irq = readl(&swdma_chan->mmio_chan_fw->int_vec);
> + dev_dbg(&pdev->dev, "Channel %d: CE irq vector %d\n", i, irq);
> +
> + rc = pci_request_irq(pdev, irq, switchtec_dma_isr, NULL, swdma_chan,
> + KBUILD_MODNAME);
> + if (rc)
> + goto free_and_exit;
> +
> + swdma_chan->irq = irq;
> +
> + spin_lock_init(&swdma_chan->hw_ctrl_lock);
> + spin_lock_init(&swdma_chan->submit_lock);
> + spin_lock_init(&swdma_chan->complete_lock);
> + tasklet_init(&swdma_chan->desc_task, switchtec_dma_desc_task,
> + (unsigned long)swdma_chan);
> +
> + chan = &swdma_chan->dma_chan;
> + chan->device = dma;
> + dma_cookie_init(chan);
> +
> + list_add_tail(&chan->device_node, &dma->channels);
> +
> + return 0;
> +
> +free_and_exit:
> + kfree(swdma_chan);
> + return rc;
> +}
> +
> +static int switchtec_dma_chan_free(struct switchtec_dma_chan *swdma_chan)
> +{
> + struct pci_dev *pdev = rcu_dereference(swdma_chan->swdma_dev->pdev);
> +
> + spin_lock_bh(&swdma_chan->submit_lock);
> + swdma_chan->ring_active = false;
> + spin_unlock_bh(&swdma_chan->submit_lock);
> +
> + spin_lock_bh(&swdma_chan->complete_lock);
> + swdma_chan->comp_ring_active = false;
> + spin_unlock_bh(&swdma_chan->complete_lock);
> +
> + pci_free_irq(pdev, swdma_chan->irq, swdma_chan);
> +
> + switchtec_dma_chan_stop(swdma_chan);
> +
> + return 0;
> +}
> +
> +static int switchtec_dma_chans_release(struct switchtec_dma_dev *swdma_dev)
> +{
> + int i;
> +
> + for (i = 0; i < swdma_dev->chan_cnt; i++)
> + switchtec_dma_chan_free(swdma_dev->swdma_chans[i]);
> +
> + return 0;
> +}
> +
> +static int switchtec_dma_chans_enumerate(struct switchtec_dma_dev *swdma_dev,
> + int chan_cnt)
> +{
> + struct dma_device *dma = &swdma_dev->dma_dev;
> + struct pci_dev *pdev = rcu_dereference(swdma_dev->pdev);
> + int base;
> + int cnt;
> + int rc;
> + int i;
> +
> + swdma_dev->swdma_chans = kcalloc(chan_cnt,
> + sizeof(*swdma_dev->swdma_chans),
> + GFP_KERNEL);
> +
> + if (!swdma_dev->swdma_chans)
> + return -ENOMEM;
> +
> + base = readw(swdma_dev->bar + SWITCHTEC_REG_SE_BUF_BASE);
> + cnt = readw(swdma_dev->bar + SWITCHTEC_REG_SE_BUF_CNT);
> +
> + dev_dbg(&pdev->dev, "EP SE buffer base %d\n", base);
> + dev_dbg(&pdev->dev, "EP SE buffer count %d\n", cnt);
> +
> + INIT_LIST_HEAD(&dma->channels);
> +
> + for (i = 0; i < chan_cnt; i++) {
> + rc = switchtec_dma_chan_init(swdma_dev, i);
> + if (rc) {
> + dev_err(&pdev->dev, "Channel %d: init channel failed\n",
> + i);
> + chan_cnt = i;
> + goto err_exit;
> + }
> + }
> +
> + return chan_cnt;
> +
> +err_exit:
> + for (i = 0; i < chan_cnt; i++)
> + switchtec_dma_chan_free(swdma_dev->swdma_chans[i]);
> +
> + kfree(swdma_dev->swdma_chans);
> +
> + return rc;
> +}
> +
> +static void switchtec_dma_release(struct dma_device *dma_dev)
> +{
> + int i;
> + struct switchtec_dma_dev *swdma_dev =
> + container_of(dma_dev, struct switchtec_dma_dev, dma_dev);
> +
> + for (i = 0; i < swdma_dev->chan_cnt; i++)
> + kfree(swdma_dev->swdma_chans[i]);
> +
> + kfree(swdma_dev->swdma_chans);
> +
> + put_device(dma_dev->dev);
> + kfree(swdma_dev);
> +}
> +
> +static int switchtec_dma_create(struct pci_dev *pdev)
> +{
> + struct switchtec_dma_dev *swdma_dev;
> + struct dma_device *dma;
> + struct dma_chan *chan;
> + int chan_cnt;
> + int nr_vecs;
> + int irq;
> + int rc;
> +
> + /*
> + * Create the switchtec dma device
> + */
> + swdma_dev = kzalloc(sizeof(*swdma_dev), GFP_KERNEL);
> + if (!swdma_dev)
> + return -ENOMEM;
> +
> + swdma_dev->bar = ioremap(pci_resource_start(pdev, 0),
> + pci_resource_len(pdev, 0));
> +
> + pci_info(pdev, "Switchtec PSX/PFX DMA EP\n");
> +
> + RCU_INIT_POINTER(swdma_dev->pdev, pdev);
> +
> + nr_vecs = pci_msix_vec_count(pdev);
> + rc = pci_alloc_irq_vectors(pdev, nr_vecs, nr_vecs, PCI_IRQ_MSIX);
> + if (rc < 0)
> + goto err_exit;
> +
> + tasklet_init(&swdma_dev->chan_status_task,
> + switchtec_dma_chan_status_task,
> + (unsigned long)swdma_dev);
> +
> + irq = readw(swdma_dev->bar + SWITCHTEC_REG_CHAN_STS_VEC);
> + pci_dbg(pdev, "Channel pause irq vector %d\n", irq);
> +
> + rc = pci_request_irq(pdev, irq, switchtec_dma_chan_status_isr, NULL,
> + swdma_dev, KBUILD_MODNAME);
> + if (rc)
> + goto err_exit;
> +
> + swdma_dev->chan_status_irq = irq;
> +
> + chan_cnt = readl(swdma_dev->bar + SWITCHTEC_REG_CHAN_CNT);
> + if (!chan_cnt) {
> + pci_err(pdev, "No channel configured.\n");
> + rc = -ENXIO;
> + goto err_exit;
> + }
> +
> + chan_cnt = switchtec_dma_chans_enumerate(swdma_dev, chan_cnt);
> + if (chan_cnt < 0) {
> + pci_err(pdev, "Failed to enumerate dma channels: %d\n",
> + chan_cnt);
> + rc = -ENXIO;
> + goto err_exit;
> + }
> +
> + swdma_dev->chan_cnt = chan_cnt;
> +
> + dma = &swdma_dev->dma_dev;
> + dma->copy_align = DMAENGINE_ALIGN_1_BYTE;
> + dma_cap_set(DMA_MEMCPY, dma->cap_mask);
> + dma_cap_set(DMA_PRIVATE, dma->cap_mask);
> + dma->dev = get_device(&pdev->dev);
> +
> + dma->device_alloc_chan_resources = switchtec_dma_alloc_chan_resources;
> + dma->device_free_chan_resources = switchtec_dma_free_chan_resources;
> + dma->device_prep_dma_memcpy = switchtec_dma_prep_memcpy;
> + dma->device_prep_dma_imm_data = switchtec_dma_prep_wimm_data;
> + dma->device_issue_pending = switchtec_dma_issue_pending;
> + dma->device_tx_status = switchtec_dma_tx_status;
> + dma->device_pause = switchtec_dma_pause;
> + dma->device_resume = switchtec_dma_resume;
> + dma->device_terminate_all = switchtec_dma_terminate_all;
> + dma->device_synchronize = switchtec_dma_synchronize;
> + dma->device_release = switchtec_dma_release;
> +
> + rc = dma_async_device_register(dma);
> + if (rc) {
> + pci_err(pdev, "Failed to register dma device: %d\n", rc);
> + goto err_chans_release_exit;
> + }
> +
> + pci_info(pdev, "Channel count: %d\n", chan_cnt);
dev_info()?
> +
> + list_for_each_entry(chan, &dma->channels, device_node)
> + pci_info(pdev, "%s\n", dma_chan_name(chan));
> +
> + pci_set_drvdata(pdev, swdma_dev);
> +
> + return 0;
> +
> +err_chans_release_exit:
> + switchtec_dma_chans_release(swdma_dev);
> +
> +err_exit:
> + if (swdma_dev->chan_status_irq)
> + free_irq(swdma_dev->chan_status_irq, swdma_dev);
> +
> + iounmap(swdma_dev->bar);
> + kfree(swdma_dev);
> + return rc;
> +}
> +
> +static int switchtec_dma_probe(struct pci_dev *pdev,
> + const struct pci_device_id *id)
> +{
> + int rc;
> +
> + rc = pci_enable_device(pdev);
> + if (rc)
> + return rc;
> +
> + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> + if (rc)
> + goto err_disable;
> +
> + rc = pci_request_mem_regions(pdev, KBUILD_MODNAME);
> + if (rc)
> + goto err_disable;
> +
> + pci_set_master(pdev);
> +
> + rc = switchtec_dma_create(pdev);
> + if (rc)
> + goto err_free;
> +
> + pci_info(pdev, "Switchtec DMA Channels Registered\n");
> +
> + return 0;
> +
> +err_free:
> + pci_free_irq_vectors(pdev);
> + pci_release_mem_regions(pdev);
> +
> +err_disable:
> + pci_disable_device(pdev);
> +
> + return rc;
> +}
> +
> +static void switchtec_dma_remove(struct pci_dev *pdev)
> +{
> + struct switchtec_dma_dev *swdma_dev = pci_get_drvdata(pdev);
> +
> + switchtec_dma_chans_release(swdma_dev);
> +
> + tasklet_kill(&swdma_dev->chan_status_task);
> +
> + rcu_assign_pointer(swdma_dev->pdev, NULL);
> + synchronize_rcu();
> +
> + pci_free_irq(pdev, swdma_dev->chan_status_irq, swdma_dev);
> +
> + pci_free_irq_vectors(pdev);
> +
> + dma_async_device_unregister(&swdma_dev->dma_dev);
> +
> + iounmap(swdma_dev->bar);
> + pci_release_mem_regions(pdev);
> + pci_disable_device(pdev);
> +
> + pci_info(pdev, "Switchtec DMA Channels Unregistered\n");
> +}
> +
> +/*
> + * Use vender/device and class to identify the DMA function.
> + */
> +#define SWITCHTEC_DMA_DEVICE(device_id) \
> + { \
> + .vendor = PCI_VENDOR_ID_MICROSEMI, \
> + .device = device_id, \
> + .subvendor = PCI_ANY_ID, \
> + .subdevice = PCI_ANY_ID, \
> + .class = PCI_CLASS_SYSTEM_OTHER << 8, \
> + .class_mask = 0xFFFFFFFF, \
> + }
> +
> +static const struct pci_device_id switchtec_dma_pci_tbl[] = {
> + SWITCHTEC_DMA_DEVICE(0x4000), /* PFX 100XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4084), /* PFX 84XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4068), /* PFX 68XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4052), /* PFX 52XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4036), /* PFX 36XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4028), /* PFX 28XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4100), /* PSX 100XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4184), /* PSX 84XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4168), /* PSX 68XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4152), /* PSX 52XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4136), /* PSX 36XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4128), /* PSX 28XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4352), /* PFXA 52XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4336), /* PFXA 36XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4328), /* PFXA 28XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4452), /* PSXA 52XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4436), /* PSXA 36XG4 */
> + SWITCHTEC_DMA_DEVICE(0x4428), /* PSXA 28XG4 */
> + {0}
> +};
> +MODULE_DEVICE_TABLE(pci, switchtec_dma_pci_tbl);
> +
> +static struct pci_driver switchtec_dma_pci_driver = {
> + .name = KBUILD_MODNAME,
> + .id_table = switchtec_dma_pci_tbl,
> + .probe = switchtec_dma_probe,
> + .remove = switchtec_dma_remove,
> +};
> +module_pci_driver(switchtec_dma_pci_driver);
> --
> 2.25.1
--
~Vinod
