This is v3 of the patchset. The in-use unbind bits have been sent and
accepted as a separate patch set. This patchset just includes the new
driver which has been updated to use the common reference counting.
This patchset is based off of vkoul/slave-dma.git/next and a git branch is
available here:
https://github.com/sbates130272/linux-p2pmem/ plx-dma-v3
Changes for v3:
* Common in-use unbind bits were submitted as a separate patch set
* Rebased onto vkoul/slave-dma.git/next (as of Jan 3rd 2020)
Changes for v2:
* Rebased onto v5.5-rc1 (no changes)
* Pushed the plx_dma_isr() routine into the patch that uses it (per
Vinod's feedback)
Logan Gunthorpe (3):
dmaengine: plx-dma: Introduce PLX DMA engine PCI driver skeleton
dmaengine: plx-dma: Implement hardware initialization and cleanup
dmaengine: plx-dma: Implement descriptor submission
MAINTAINERS | 5 +
drivers/dma/Kconfig | 9 +
drivers/dma/Makefile | 1 +
drivers/dma/plx_dma.c | 639 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 654 insertions(+)
create mode 100644 drivers/dma/plx_dma.c
--
2.20.1
On prep, a spin lock is taken and the next entry in the circular buffer
is filled. On submit, the valid bit is set in the hardware descriptor
and the lock is released.
The DMA engine is started (if it's not already running) when the client
calls dma_async_issue_pending().
Signed-off-by: Logan Gunthorpe <[email protected]>
---
drivers/dma/plx_dma.c | 119 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c
index f3a5c9e47658..db4c5fd453a9 100644
--- a/drivers/dma/plx_dma.c
+++ b/drivers/dma/plx_dma.c
@@ -7,6 +7,7 @@
#include "dmaengine.h"
+#include <linux/circ_buf.h>
#include <linux/dmaengine.h>
#include <linux/kref.h>
#include <linux/list.h>
@@ -120,6 +121,11 @@ 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)];
@@ -242,6 +248,113 @@ static void plx_dma_desc_task(unsigned long data)
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;
@@ -276,7 +389,9 @@ static int plx_dma_alloc_desc(struct plx_dma_dev *plxdev)
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;
}
@@ -407,11 +522,15 @@ static int plx_dma_create(struct pci_dev *pdev)
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;
--
2.20.1
Some PLX Switches can expose DMA engines via extra PCI functions
on the upstream port. Each function will have one DMA channel.
This patch is just the core PCI driver skeleton and dma
engine registration.
Signed-off-by: Logan Gunthorpe <[email protected]>
---
MAINTAINERS | 5 ++
drivers/dma/Kconfig | 9 +++
drivers/dma/Makefile | 1 +
drivers/dma/plx_dma.c | 150 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 165 insertions(+)
create mode 100644 drivers/dma/plx_dma.c
diff --git a/MAINTAINERS b/MAINTAINERS
index bd5847e802de..76713226f256 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13139,6 +13139,11 @@ S: Maintained
F: drivers/iio/chemical/pms7003.c
F: Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml
+PLX DMA DRIVER
+M: Logan Gunthorpe <[email protected]>
+S: Maintained
+F: drivers/dma/plx_dma.c
+
PMBUS HARDWARE MONITORING DRIVERS
M: Guenter Roeck <[email protected]>
L: [email protected]
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6fa1eba9d477..312a6cc36c78 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -497,6 +497,15 @@ config PXA_DMA
16 to 32 channels for peripheral to memory or memory to memory
transfers.
+config PLX_DMA
+ tristate "PLX ExpressLane PEX Switch DMA Engine Support"
+ depends on PCI
+ select DMA_ENGINE
+ help
+ Some PLX ExpressLane PCI Switches support additional DMA engines.
+ These are exposed via extra functions on the switch's
+ upstream port. Each function exposes one DMA channel.
+
config SIRF_DMA
tristate "CSR SiRFprimaII/SiRFmarco DMA support"
depends on ARCH_SIRF
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 42d7e2fc64fa..a150d1d792fd 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
obj-$(CONFIG_OWL_DMA) += owl-dma.o
obj-$(CONFIG_PCH_DMA) += pch_dma.o
obj-$(CONFIG_PL330_DMA) += pl330.o
+obj-$(CONFIG_PLX_DMA) += plx_dma.o
obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
obj-$(CONFIG_PXA_DMA) += pxa_dma.o
obj-$(CONFIG_RENESAS_DMA) += sh/
diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c
new file mode 100644
index 000000000000..e002cbb7d2b6
--- /dev/null
+++ b/drivers/dma/plx_dma.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microsemi Switchtec(tm) PCIe Management Driver
+ * Copyright (c) 2019, Logan Gunthorpe <[email protected]>
+ * Copyright (c) 2019, GigaIO Networks, Inc
+ */
+
+#include "dmaengine.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");
+
+struct plx_dma_dev {
+ struct dma_device dma_dev;
+ struct dma_chan dma_chan;
+ void __iomem *bar;
+};
+
+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;
+
+ plxdev->bar = pcim_iomap_table(pdev)[0];
+
+ dma = &plxdev->dma_dev;
+ dma->chancnt = 1;
+ INIT_LIST_HEAD(&dma->channels);
+ dma->copy_align = DMAENGINE_ALIGN_1_BYTE;
+ dma->dev = get_device(&pdev->dev);
+
+ 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);
+
+ 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);
--
2.20.1
Allocate DMA coherent memory for the ring of DMA descriptors and
program the appropriate hardware registers.
A tasklet is created which is triggered on an interrupt to process
all the finished requests. Additionally, any remaining descriptors
are aborted when the hardware is removed or the resources freed.
Use an RCU pointer to synchronize PCI device unbind.
Signed-off-by: Logan Gunthorpe <[email protected]>
---
drivers/dma/plx_dma.c | 370 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 370 insertions(+)
diff --git a/drivers/dma/plx_dma.c b/drivers/dma/plx_dma.c
index e002cbb7d2b6..f3a5c9e47658 100644
--- a/drivers/dma/plx_dma.c
+++ b/drivers/dma/plx_dma.c
@@ -18,12 +18,358 @@ 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 *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(unsigned long data)
+{
+ struct plx_dma_dev *plxdev = (void *)data;
+
+ plx_dma_process_desc(plxdev);
+}
+
+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->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 =
@@ -44,6 +390,18 @@ static int plx_dma_create(struct pci_dev *pdev)
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_init(&plxdev->desc_task, plx_dma_desc_task,
+ (unsigned long)plxdev);
+
+ RCU_INIT_POINTER(plxdev->pdev, pdev);
plxdev->bar = pcim_iomap_table(pdev)[0];
dma = &plxdev->dma_dev;
@@ -52,6 +410,8 @@ static int plx_dma_create(struct pci_dev *pdev)
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_release = plx_dma_release;
chan = &plxdev->dma_chan;
@@ -122,6 +482,16 @@ static void plx_dma_remove(struct pci_dev *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);
--
2.20.1
On 03-01-20, 14:20, Logan Gunthorpe wrote:
> This is v3 of the patchset. The in-use unbind bits have been sent and
> accepted as a separate patch set. This patchset just includes the new
> driver which has been updated to use the common reference counting.
>
> This patchset is based off of vkoul/slave-dma.git/next and a git branch is
> available here:
>
> https://github.com/sbates130272/linux-p2pmem/ plx-dma-v3
Applied all, thanks, apologies for delay!
--
~Vinod