linux-stable/drivers/dma/plx_dma.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Microsemi Switchtec(tm) PCIe Management Driver
* Copyright (c) 2019, Logan Gunthorpe <logang@deltatee.com>
* Copyright (c) 2019, GigaIO Networks, Inc
*/
#include "dmaengine.h"
#include <linux/circ_buf.h>
#include <linux/dmaengine.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/pci.h>
MODULE_DESCRIPTION("PLX ExpressLane PEX PCI Switch DMA Engine");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Logan Gunthorpe");
#define PLX_REG_DESC_RING_ADDR 0x214
#define PLX_REG_DESC_RING_ADDR_HI 0x218
#define PLX_REG_DESC_RING_NEXT_ADDR 0x21C
#define PLX_REG_DESC_RING_COUNT 0x220
#define PLX_REG_DESC_RING_LAST_ADDR 0x224
#define PLX_REG_DESC_RING_LAST_SIZE 0x228
#define PLX_REG_PREF_LIMIT 0x234
#define PLX_REG_CTRL 0x238
#define PLX_REG_CTRL2 0x23A
#define PLX_REG_INTR_CTRL 0x23C
#define PLX_REG_INTR_STATUS 0x23E
#define PLX_REG_PREF_LIMIT_PREF_FOUR 8
#define PLX_REG_CTRL_GRACEFUL_PAUSE BIT(0)
#define PLX_REG_CTRL_ABORT BIT(1)
#define PLX_REG_CTRL_WRITE_BACK_EN BIT(2)
#define PLX_REG_CTRL_START BIT(3)
#define PLX_REG_CTRL_RING_STOP_MODE BIT(4)
#define PLX_REG_CTRL_DESC_MODE_BLOCK (0 << 5)
#define PLX_REG_CTRL_DESC_MODE_ON_CHIP (1 << 5)
#define PLX_REG_CTRL_DESC_MODE_OFF_CHIP (2 << 5)
#define PLX_REG_CTRL_DESC_INVALID BIT(8)
#define PLX_REG_CTRL_GRACEFUL_PAUSE_DONE BIT(9)
#define PLX_REG_CTRL_ABORT_DONE BIT(10)
#define PLX_REG_CTRL_IMM_PAUSE_DONE BIT(12)
#define PLX_REG_CTRL_IN_PROGRESS BIT(30)
#define PLX_REG_CTRL_RESET_VAL (PLX_REG_CTRL_DESC_INVALID | \
PLX_REG_CTRL_GRACEFUL_PAUSE_DONE | \
PLX_REG_CTRL_ABORT_DONE | \
PLX_REG_CTRL_IMM_PAUSE_DONE)
#define PLX_REG_CTRL_START_VAL (PLX_REG_CTRL_WRITE_BACK_EN | \
PLX_REG_CTRL_DESC_MODE_OFF_CHIP | \
PLX_REG_CTRL_START | \
PLX_REG_CTRL_RESET_VAL)
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_64B 0
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_128B 1
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_256B 2
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_512B 3
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_1KB 4
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_2KB 5
#define PLX_REG_CTRL2_MAX_TXFR_SIZE_4B 7
#define PLX_REG_INTR_CRTL_ERROR_EN BIT(0)
#define PLX_REG_INTR_CRTL_INV_DESC_EN BIT(1)
#define PLX_REG_INTR_CRTL_ABORT_DONE_EN BIT(3)
#define PLX_REG_INTR_CRTL_PAUSE_DONE_EN BIT(4)
#define PLX_REG_INTR_CRTL_IMM_PAUSE_DONE_EN BIT(5)
#define PLX_REG_INTR_STATUS_ERROR BIT(0)
#define PLX_REG_INTR_STATUS_INV_DESC BIT(1)
#define PLX_REG_INTR_STATUS_DESC_DONE BIT(2)
#define PLX_REG_INTR_CRTL_ABORT_DONE BIT(3)
struct plx_dma_hw_std_desc {
__le32 flags_and_size;
__le16 dst_addr_hi;
__le16 src_addr_hi;
__le32 dst_addr_lo;
__le32 src_addr_lo;
};
#define PLX_DESC_SIZE_MASK 0x7ffffff
#define PLX_DESC_FLAG_VALID BIT(31)
#define PLX_DESC_FLAG_INT_WHEN_DONE BIT(30)
#define PLX_DESC_WB_SUCCESS BIT(30)
#define PLX_DESC_WB_RD_FAIL BIT(29)
#define PLX_DESC_WB_WR_FAIL BIT(28)
#define PLX_DMA_RING_COUNT 2048
struct plx_dma_desc {
struct dma_async_tx_descriptor txd;
struct plx_dma_hw_std_desc *hw;
u32 orig_size;
};
struct plx_dma_dev {
struct dma_device dma_dev;
struct dma_chan dma_chan;
struct pci_dev __rcu *pdev;
void __iomem *bar;
struct tasklet_struct desc_task;
spinlock_t ring_lock;
bool ring_active;
int head;
int tail;
struct plx_dma_hw_std_desc *hw_ring;
dma_addr_t hw_ring_dma;
struct plx_dma_desc **desc_ring;
};
static struct plx_dma_dev *chan_to_plx_dma_dev(struct dma_chan *c)
{
return container_of(c, struct plx_dma_dev, dma_chan);
}
static struct plx_dma_desc *to_plx_desc(struct dma_async_tx_descriptor *txd)
{
return container_of(txd, struct plx_dma_desc, txd);
}
static struct plx_dma_desc *plx_dma_get_desc(struct plx_dma_dev *plxdev, int i)
{
return plxdev->desc_ring[i & (PLX_DMA_RING_COUNT - 1)];
}
static void plx_dma_process_desc(struct plx_dma_dev *plxdev)
{
struct dmaengine_result res;
struct plx_dma_desc *desc;
u32 flags;
spin_lock_bh(&plxdev->ring_lock);
while (plxdev->tail != plxdev->head) {
desc = plx_dma_get_desc(plxdev, plxdev->tail);
flags = le32_to_cpu(READ_ONCE(desc->hw->flags_and_size));
if (flags & PLX_DESC_FLAG_VALID)
break;
res.residue = desc->orig_size - (flags & PLX_DESC_SIZE_MASK);
if (flags & PLX_DESC_WB_SUCCESS)
res.result = DMA_TRANS_NOERROR;
else if (flags & PLX_DESC_WB_WR_FAIL)
res.result = DMA_TRANS_WRITE_FAILED;
else
res.result = DMA_TRANS_READ_FAILED;
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;
plxdev->tail++;
}
spin_unlock_bh(&plxdev->ring_lock);
}
static void plx_dma_abort_desc(struct plx_dma_dev *plxdev)
{
struct dmaengine_result res;
struct plx_dma_desc *desc;
plx_dma_process_desc(plxdev);
spin_lock_bh(&plxdev->ring_lock);
while (plxdev->tail != plxdev->head) {
desc = plx_dma_get_desc(plxdev, plxdev->tail);
res.residue = desc->orig_size;
res.result = DMA_TRANS_ABORTED;
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;
plxdev->tail++;
}
spin_unlock_bh(&plxdev->ring_lock);
}
static void __plx_dma_stop(struct plx_dma_dev *plxdev)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
u32 val;
val = readl(plxdev->bar + PLX_REG_CTRL);
if (!(val & ~PLX_REG_CTRL_GRACEFUL_PAUSE))
return;
writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE,
plxdev->bar + PLX_REG_CTRL);
while (!time_after(jiffies, timeout)) {
val = readl(plxdev->bar + PLX_REG_CTRL);
if (val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE)
break;
cpu_relax();
}
if (!(val & PLX_REG_CTRL_GRACEFUL_PAUSE_DONE))
dev_err(plxdev->dma_dev.dev,
"Timeout waiting for graceful pause!\n");
writel(PLX_REG_CTRL_RESET_VAL | PLX_REG_CTRL_GRACEFUL_PAUSE,
plxdev->bar + PLX_REG_CTRL);
writel(0, plxdev->bar + PLX_REG_DESC_RING_COUNT);
writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR);
writel(0, plxdev->bar + PLX_REG_DESC_RING_ADDR_HI);
writel(0, plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR);
}
static void plx_dma_stop(struct plx_dma_dev *plxdev)
{
rcu_read_lock();
if (!rcu_dereference(plxdev->pdev)) {
rcu_read_unlock();
return;
}
__plx_dma_stop(plxdev);
rcu_read_unlock();
}
static void plx_dma_desc_task(struct tasklet_struct *t)
{
struct plx_dma_dev *plxdev = from_tasklet(plxdev, t, desc_task);
plx_dma_process_desc(plxdev);
}
static struct dma_async_tx_descriptor *plx_dma_prep_memcpy(struct dma_chan *c,
dma_addr_t dma_dst, dma_addr_t dma_src, size_t len,
unsigned long flags)
__acquires(plxdev->ring_lock)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(c);
struct plx_dma_desc *plxdesc;
spin_lock_bh(&plxdev->ring_lock);
if (!plxdev->ring_active)
goto err_unlock;
if (!CIRC_SPACE(plxdev->head, plxdev->tail, PLX_DMA_RING_COUNT))
goto err_unlock;
if (len > PLX_DESC_SIZE_MASK)
goto err_unlock;
plxdesc = plx_dma_get_desc(plxdev, plxdev->head);
plxdev->head++;
plxdesc->hw->dst_addr_lo = cpu_to_le32(lower_32_bits(dma_dst));
plxdesc->hw->dst_addr_hi = cpu_to_le16(upper_32_bits(dma_dst));
plxdesc->hw->src_addr_lo = cpu_to_le32(lower_32_bits(dma_src));
plxdesc->hw->src_addr_hi = cpu_to_le16(upper_32_bits(dma_src));
plxdesc->orig_size = len;
if (flags & DMA_PREP_INTERRUPT)
len |= PLX_DESC_FLAG_INT_WHEN_DONE;
plxdesc->hw->flags_and_size = cpu_to_le32(len);
plxdesc->txd.flags = flags;
/* return with the lock held, it will be released in tx_submit */
return &plxdesc->txd;
err_unlock:
/*
* Keep sparse happy by restoring an even lock count on
* this lock.
*/
__acquire(plxdev->ring_lock);
spin_unlock_bh(&plxdev->ring_lock);
return NULL;
}
static dma_cookie_t plx_dma_tx_submit(struct dma_async_tx_descriptor *desc)
__releases(plxdev->ring_lock)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(desc->chan);
struct plx_dma_desc *plxdesc = to_plx_desc(desc);
dma_cookie_t cookie;
cookie = dma_cookie_assign(desc);
/*
* Ensure the descriptor updates are visible to the dma device
* before setting the valid bit.
*/
wmb();
plxdesc->hw->flags_and_size |= cpu_to_le32(PLX_DESC_FLAG_VALID);
spin_unlock_bh(&plxdev->ring_lock);
return cookie;
}
static enum dma_status plx_dma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie, struct dma_tx_state *txstate)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
enum dma_status ret;
ret = dma_cookie_status(chan, cookie, txstate);
if (ret == DMA_COMPLETE)
return ret;
plx_dma_process_desc(plxdev);
return dma_cookie_status(chan, cookie, txstate);
}
static void plx_dma_issue_pending(struct dma_chan *chan)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
rcu_read_lock();
if (!rcu_dereference(plxdev->pdev)) {
rcu_read_unlock();
return;
}
/*
* Ensure the valid bits are visible before starting the
* DMA engine.
*/
wmb();
writew(PLX_REG_CTRL_START_VAL, plxdev->bar + PLX_REG_CTRL);
rcu_read_unlock();
}
static irqreturn_t plx_dma_isr(int irq, void *devid)
{
struct plx_dma_dev *plxdev = devid;
u32 status;
status = readw(plxdev->bar + PLX_REG_INTR_STATUS);
if (!status)
return IRQ_NONE;
if (status & PLX_REG_INTR_STATUS_DESC_DONE && plxdev->ring_active)
tasklet_schedule(&plxdev->desc_task);
writew(status, plxdev->bar + PLX_REG_INTR_STATUS);
return IRQ_HANDLED;
}
static int plx_dma_alloc_desc(struct plx_dma_dev *plxdev)
{
struct plx_dma_desc *desc;
int i;
plxdev->desc_ring = kcalloc(PLX_DMA_RING_COUNT,
sizeof(*plxdev->desc_ring), GFP_KERNEL);
if (!plxdev->desc_ring)
return -ENOMEM;
for (i = 0; i < PLX_DMA_RING_COUNT; i++) {
desc = kzalloc(sizeof(*desc), GFP_KERNEL);
if (!desc)
goto free_and_exit;
dma_async_tx_descriptor_init(&desc->txd, &plxdev->dma_chan);
desc->txd.tx_submit = plx_dma_tx_submit;
desc->hw = &plxdev->hw_ring[i];
plxdev->desc_ring[i] = desc;
}
return 0;
free_and_exit:
for (i = 0; i < PLX_DMA_RING_COUNT; i++)
kfree(plxdev->desc_ring[i]);
kfree(plxdev->desc_ring);
return -ENOMEM;
}
static int plx_dma_alloc_chan_resources(struct dma_chan *chan)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
size_t ring_sz = PLX_DMA_RING_COUNT * sizeof(*plxdev->hw_ring);
int rc;
plxdev->head = plxdev->tail = 0;
plxdev->hw_ring = dma_alloc_coherent(plxdev->dma_dev.dev, ring_sz,
&plxdev->hw_ring_dma, GFP_KERNEL);
if (!plxdev->hw_ring)
return -ENOMEM;
rc = plx_dma_alloc_desc(plxdev);
if (rc)
goto out_free_hw_ring;
rcu_read_lock();
if (!rcu_dereference(plxdev->pdev)) {
rcu_read_unlock();
rc = -ENODEV;
goto out_free_hw_ring;
}
writel(PLX_REG_CTRL_RESET_VAL, plxdev->bar + PLX_REG_CTRL);
writel(lower_32_bits(plxdev->hw_ring_dma),
plxdev->bar + PLX_REG_DESC_RING_ADDR);
writel(upper_32_bits(plxdev->hw_ring_dma),
plxdev->bar + PLX_REG_DESC_RING_ADDR_HI);
writel(lower_32_bits(plxdev->hw_ring_dma),
plxdev->bar + PLX_REG_DESC_RING_NEXT_ADDR);
writel(PLX_DMA_RING_COUNT, plxdev->bar + PLX_REG_DESC_RING_COUNT);
writel(PLX_REG_PREF_LIMIT_PREF_FOUR, plxdev->bar + PLX_REG_PREF_LIMIT);
plxdev->ring_active = true;
rcu_read_unlock();
return PLX_DMA_RING_COUNT;
out_free_hw_ring:
dma_free_coherent(plxdev->dma_dev.dev, ring_sz, plxdev->hw_ring,
plxdev->hw_ring_dma);
return rc;
}
static void plx_dma_free_chan_resources(struct dma_chan *chan)
{
struct plx_dma_dev *plxdev = chan_to_plx_dma_dev(chan);
size_t ring_sz = PLX_DMA_RING_COUNT * sizeof(*plxdev->hw_ring);
struct pci_dev *pdev;
int irq = -1;
int i;
spin_lock_bh(&plxdev->ring_lock);
plxdev->ring_active = false;
spin_unlock_bh(&plxdev->ring_lock);
plx_dma_stop(plxdev);
rcu_read_lock();
pdev = rcu_dereference(plxdev->pdev);
if (pdev)
irq = pci_irq_vector(pdev, 0);
rcu_read_unlock();
if (irq > 0)
synchronize_irq(irq);
tasklet_kill(&plxdev->desc_task);
plx_dma_abort_desc(plxdev);
for (i = 0; i < PLX_DMA_RING_COUNT; i++)
kfree(plxdev->desc_ring[i]);
kfree(plxdev->desc_ring);
dma_free_coherent(plxdev->dma_dev.dev, ring_sz, plxdev->hw_ring,
plxdev->hw_ring_dma);
}
static void plx_dma_release(struct dma_device *dma_dev)
{
struct plx_dma_dev *plxdev =
container_of(dma_dev, struct plx_dma_dev, dma_dev);
put_device(dma_dev->dev);
kfree(plxdev);
}
static int plx_dma_create(struct pci_dev *pdev)
{
struct plx_dma_dev *plxdev;
struct dma_device *dma;
struct dma_chan *chan;
int rc;
plxdev = kzalloc(sizeof(*plxdev), GFP_KERNEL);
if (!plxdev)
return -ENOMEM;
rc = request_irq(pci_irq_vector(pdev, 0), plx_dma_isr, 0,
KBUILD_MODNAME, plxdev);
if (rc) {
kfree(plxdev);
return rc;
}
spin_lock_init(&plxdev->ring_lock);
tasklet_setup(&plxdev->desc_task, plx_dma_desc_task);
RCU_INIT_POINTER(plxdev->pdev, pdev);
plxdev->bar = pcim_iomap_table(pdev)[0];
dma = &plxdev->dma_dev;
dma->chancnt = 1;
INIT_LIST_HEAD(&dma->channels);
dma_cap_set(DMA_MEMCPY, dma->cap_mask);
dma->copy_align = DMAENGINE_ALIGN_1_BYTE;
dma->dev = get_device(&pdev->dev);
dma->device_alloc_chan_resources = plx_dma_alloc_chan_resources;
dma->device_free_chan_resources = plx_dma_free_chan_resources;
dma->device_prep_dma_memcpy = plx_dma_prep_memcpy;
dma->device_issue_pending = plx_dma_issue_pending;
dma->device_tx_status = plx_dma_tx_status;
dma->device_release = plx_dma_release;
chan = &plxdev->dma_chan;
chan->device = dma;
dma_cookie_init(chan);
list_add_tail(&chan->device_node, &dma->channels);
rc = dma_async_device_register(dma);
if (rc) {
pci_err(pdev, "Failed to register dma device: %d\n", rc);
free_irq(pci_irq_vector(pdev, 0), plxdev);
kfree(plxdev);
return rc;
}
pci_set_drvdata(pdev, plxdev);
return 0;
}
static int plx_dma_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
int rc;
rc = pcim_enable_device(pdev);
if (rc)
return rc;
rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(48));
if (rc)
rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
if (rc)
return rc;
rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(48));
if (rc)
rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
if (rc)
return rc;
rc = pcim_iomap_regions(pdev, 1, KBUILD_MODNAME);
if (rc)
return rc;
rc = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
if (rc <= 0)
return rc;
pci_set_master(pdev);
rc = plx_dma_create(pdev);
if (rc)
goto err_free_irq_vectors;
pci_info(pdev, "PLX DMA Channel Registered\n");
return 0;
err_free_irq_vectors:
pci_free_irq_vectors(pdev);
return rc;
}
static void plx_dma_remove(struct pci_dev *pdev)
{
struct plx_dma_dev *plxdev = pci_get_drvdata(pdev);
free_irq(pci_irq_vector(pdev, 0), plxdev);
rcu_assign_pointer(plxdev->pdev, NULL);
synchronize_rcu();
spin_lock_bh(&plxdev->ring_lock);
plxdev->ring_active = false;
spin_unlock_bh(&plxdev->ring_lock);
__plx_dma_stop(plxdev);
plx_dma_abort_desc(plxdev);
plxdev->bar = NULL;
dma_async_device_unregister(&plxdev->dma_dev);
pci_free_irq_vectors(pdev);
}
static const struct pci_device_id plx_dma_pci_tbl[] = {
{
.vendor = PCI_VENDOR_ID_PLX,
.device = 0x87D0,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.class = PCI_CLASS_SYSTEM_OTHER << 8,
.class_mask = 0xFFFFFFFF,
},
{0}
};
MODULE_DEVICE_TABLE(pci, plx_dma_pci_tbl);
static struct pci_driver plx_dma_pci_driver = {
.name = KBUILD_MODNAME,
.id_table = plx_dma_pci_tbl,
.probe = plx_dma_probe,
.remove = plx_dma_remove,
};
module_pci_driver(plx_dma_pci_driver);