[v4,1/5] net: wan: Add support for QMC HDLC
Commit Message
The QMC HDLC driver provides support for HDLC using the QMC (QUICC
Multichannel Controller) to transfer the HDLC data.
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Jakub Kicinski <kuba@kernel.org>
---
drivers/net/wan/Kconfig | 12 +
drivers/net/wan/Makefile | 1 +
drivers/net/wan/fsl_qmc_hdlc.c | 426 +++++++++++++++++++++++++++++++++
3 files changed, 439 insertions(+)
create mode 100644 drivers/net/wan/fsl_qmc_hdlc.c
Comments
On Thu, Feb 22, 2024 at 03:22:14PM +0100, Herve Codina wrote:
> The QMC HDLC driver provides support for HDLC using the QMC (QUICC
> Multichannel Controller) to transfer the HDLC data.
..
> +struct qmc_hdlc {
> + struct device *dev;
> + struct qmc_chan *qmc_chan;
> + struct net_device *netdev;
> + bool is_crc32;
> + spinlock_t tx_lock; /* Protect tx descriptors */
Just wondering if above tx/rx descriptors should be aligned on a cacheline
for DMA?
> + struct qmc_hdlc_desc tx_descs[8];
> + unsigned int tx_out;
> + struct qmc_hdlc_desc rx_descs[4];
> +};
..
> +#define QMC_HDLC_RX_ERROR_FLAGS (QMC_RX_FLAG_HDLC_OVF | \
> + QMC_RX_FLAG_HDLC_UNA | \
> + QMC_RX_FLAG_HDLC_ABORT | \
> + QMC_RX_FLAG_HDLC_CRC)
Wouldn't be slightly better to have it as
#define QMC_HDLC_RX_ERROR_FLAGS \
(QMC_RX_FLAG_HDLC_OVF | QMC_RX_FLAG_HDLC_UNA | \
QMC_RX_FLAG_HDLC_CRC | QMC_RX_FLAG_HDLC_ABORT)
?
..
> + ret = qmc_chan_write_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
> + qmc_hdlc_xmit_complete, desc);
> + if (ret) {
> + dev_err(qmc_hdlc->dev, "qmc chan write returns %d\n", ret);
> + dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
> + return ret;
I would do other way around, i.e. release resource followed up by printing
a message. Printing a message is a slow operation and may prevent the (soon
freed) resources to be re-used earlier.
> + }
..
> + spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
Why not using cleanup.h from day 1?
> +end:
This label, in particular, will not be needed with above in place.
> + spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
> + return ret;
> +}
..
> + /* Queue as many recv descriptors as possible */
> + for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
> + desc = &qmc_hdlc->rx_descs[i];
> +
> + desc->netdev = netdev;
> + ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, chan_param.hdlc.max_rx_buf_size);
> + if (ret) {
> + if (ret == -EBUSY && i != 0)
> + break; /* We use all the QMC chan capability */
> + goto free_desc;
> + }
Can be unfolded to
if (ret == -EBUSY && i)
break; /* We use all the QMC chan capability */
if (ret)
goto free_desc;
Easy to read and understand.
> + }
..
> +static int qmc_hdlc_probe(struct platform_device *pdev)
> +{
With
struct device *dev = &pdev->dev;
the below code will be neater (see other comments for the examples).
> + struct device_node *np = pdev->dev.of_node;
It is used only once, drop it (see below).
> + struct qmc_hdlc *qmc_hdlc;
> + struct qmc_chan_info info;
> + hdlc_device *hdlc;
> + int ret;
> +
> + qmc_hdlc = devm_kzalloc(&pdev->dev, sizeof(*qmc_hdlc), GFP_KERNEL);
> + if (!qmc_hdlc)
> + return -ENOMEM;
> +
> + qmc_hdlc->dev = &pdev->dev;
> + spin_lock_init(&qmc_hdlc->tx_lock);
> +
> + qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(qmc_hdlc->dev, np);
qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(dev, dev->of_node);
> + if (IS_ERR(qmc_hdlc->qmc_chan)) {
> + ret = PTR_ERR(qmc_hdlc->qmc_chan);
> + return dev_err_probe(qmc_hdlc->dev, ret, "get QMC channel failed\n");
return dev_err_probe(dev, PTR_ERR(qmc_hdlc->qmc_chan), "get QMC channel failed\n");
> + }
> +
> + ret = qmc_chan_get_info(qmc_hdlc->qmc_chan, &info);
> + if (ret) {
> + dev_err(qmc_hdlc->dev, "get QMC channel info failed %d\n", ret);
> + return ret;
Why not using same message pattern everywhere, i.e. dev_err_probe()?
return dev_err_probe(dev, ret, "get QMC channel info failed\n");
(and so on...)
> + }
> +
> + if (info.mode != QMC_HDLC) {
> + dev_err(qmc_hdlc->dev, "QMC chan mode %d is not QMC_HDLC\n",
> + info.mode);
> + return -EINVAL;
> + }
> +
> + qmc_hdlc->netdev = alloc_hdlcdev(qmc_hdlc);
> + if (!qmc_hdlc->netdev) {
> + dev_err(qmc_hdlc->dev, "failed to alloc hdlc dev\n");
> + return -ENOMEM;
We do not issue a message for -ENOMEM.
> + }
> +
> + hdlc = dev_to_hdlc(qmc_hdlc->netdev);
> + hdlc->attach = qmc_hdlc_attach;
> + hdlc->xmit = qmc_hdlc_xmit;
> + SET_NETDEV_DEV(qmc_hdlc->netdev, qmc_hdlc->dev);
> + qmc_hdlc->netdev->tx_queue_len = ARRAY_SIZE(qmc_hdlc->tx_descs);
> + qmc_hdlc->netdev->netdev_ops = &qmc_hdlc_netdev_ops;
> + ret = register_hdlc_device(qmc_hdlc->netdev);
> + if (ret) {
> + dev_err(qmc_hdlc->dev, "failed to register hdlc device (%d)\n", ret);
> + goto free_netdev;
> + }
> +
> + platform_set_drvdata(pdev, qmc_hdlc);
> +
> + return 0;
> +
> +free_netdev:
> + free_netdev(qmc_hdlc->netdev);
> + return ret;
> +}
On Thu, 22 Feb 2024 17:29:05 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> On Thu, Feb 22, 2024 at 03:22:14PM +0100, Herve Codina wrote:
> > The QMC HDLC driver provides support for HDLC using the QMC (QUICC
> > Multichannel Controller) to transfer the HDLC data.
>
> ...
>
> > +struct qmc_hdlc {
> > + struct device *dev;
> > + struct qmc_chan *qmc_chan;
> > + struct net_device *netdev;
> > + bool is_crc32;
> > + spinlock_t tx_lock; /* Protect tx descriptors */
>
> Just wondering if above tx/rx descriptors should be aligned on a cacheline
> for DMA?
These descriptors are not used by DMA.
Not sure that aligning them to a cacheline is really needed.
>
> > + struct qmc_hdlc_desc tx_descs[8];
> > + unsigned int tx_out;
> > + struct qmc_hdlc_desc rx_descs[4];
> > +};
>
> ...
>
> > +#define QMC_HDLC_RX_ERROR_FLAGS (QMC_RX_FLAG_HDLC_OVF | \
> > + QMC_RX_FLAG_HDLC_UNA | \
> > + QMC_RX_FLAG_HDLC_ABORT | \
> > + QMC_RX_FLAG_HDLC_CRC)
>
> Wouldn't be slightly better to have it as
>
> #define QMC_HDLC_RX_ERROR_FLAGS \
> (QMC_RX_FLAG_HDLC_OVF | QMC_RX_FLAG_HDLC_UNA | \
> QMC_RX_FLAG_HDLC_CRC | QMC_RX_FLAG_HDLC_ABORT)
>
> ?
Will be done in the next iteration.
>
> ...
>
> > + ret = qmc_chan_write_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
> > + qmc_hdlc_xmit_complete, desc);
> > + if (ret) {
>
> > + dev_err(qmc_hdlc->dev, "qmc chan write returns %d\n", ret);
> > + dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
> > + return ret;
>
> I would do other way around, i.e. release resource followed up by printing
> a message. Printing a message is a slow operation and may prevent the (soon
> freed) resources to be re-used earlier.
Will do that in the next iteration.
>
> > + }
>
> ...
>
> > + spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
>
> Why not using cleanup.h from day 1?
I don't know about cleanup.h.
Can you tell me more ?
How should I use it ?
>
> > +end:
>
> This label, in particular, will not be needed with above in place.
>
> > + spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
> > + return ret;
> > +}
>
> ...
>
> > + /* Queue as many recv descriptors as possible */
> > + for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
> > + desc = &qmc_hdlc->rx_descs[i];
> > +
> > + desc->netdev = netdev;
> > + ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, chan_param.hdlc.max_rx_buf_size);
>
> > + if (ret) {
> > + if (ret == -EBUSY && i != 0)
> > + break; /* We use all the QMC chan capability */
> > + goto free_desc;
> > + }
>
> Can be unfolded to
>
> if (ret == -EBUSY && i)
> break; /* We use all the QMC chan capability */
> if (ret)
> goto free_desc;
>
> Easy to read and understand.
Sure, will be changed.
>
> > + }
>
> ...
>
> > +static int qmc_hdlc_probe(struct platform_device *pdev)
> > +{
>
> With
>
> struct device *dev = &pdev->dev;
>
> the below code will be neater (see other comments for the examples).
Will use that.
>
> > + struct device_node *np = pdev->dev.of_node;
>
> It is used only once, drop it (see below).
Ok.
>
> > + struct qmc_hdlc *qmc_hdlc;
> > + struct qmc_chan_info info;
> > + hdlc_device *hdlc;
> > + int ret;
> > +
> > + qmc_hdlc = devm_kzalloc(&pdev->dev, sizeof(*qmc_hdlc), GFP_KERNEL);
> > + if (!qmc_hdlc)
> > + return -ENOMEM;
> > +
> > + qmc_hdlc->dev = &pdev->dev;
> > + spin_lock_init(&qmc_hdlc->tx_lock);
> > +
> > + qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(qmc_hdlc->dev, np);
>
> qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(dev, dev->of_node);
>
> > + if (IS_ERR(qmc_hdlc->qmc_chan)) {
> > + ret = PTR_ERR(qmc_hdlc->qmc_chan);
> > + return dev_err_probe(qmc_hdlc->dev, ret, "get QMC channel failed\n");
>
> return dev_err_probe(dev, PTR_ERR(qmc_hdlc->qmc_chan), "get QMC channel failed\n");
>
> > + }
> > +
> > + ret = qmc_chan_get_info(qmc_hdlc->qmc_chan, &info);
> > + if (ret) {
>
> > + dev_err(qmc_hdlc->dev, "get QMC channel info failed %d\n", ret);
> > + return ret;
>
> Why not using same message pattern everywhere, i.e. dev_err_probe()?
>
> return dev_err_probe(dev, ret, "get QMC channel info failed\n");
>
> (and so on...)
No reason. Just because I missed them.
Will be updated using dev_err_probe().
>
> > + }
> > +
> > + if (info.mode != QMC_HDLC) {
> > + dev_err(qmc_hdlc->dev, "QMC chan mode %d is not QMC_HDLC\n",
> > + info.mode);
> > + return -EINVAL;
> > + }
> > +
> > + qmc_hdlc->netdev = alloc_hdlcdev(qmc_hdlc);
> > + if (!qmc_hdlc->netdev) {
>
> > + dev_err(qmc_hdlc->dev, "failed to alloc hdlc dev\n");
> > + return -ENOMEM;
>
> We do not issue a message for -ENOMEM.
And I know :(
Will be updated.
>
> > + }
> > +
> > + hdlc = dev_to_hdlc(qmc_hdlc->netdev);
> > + hdlc->attach = qmc_hdlc_attach;
> > + hdlc->xmit = qmc_hdlc_xmit;
> > + SET_NETDEV_DEV(qmc_hdlc->netdev, qmc_hdlc->dev);
> > + qmc_hdlc->netdev->tx_queue_len = ARRAY_SIZE(qmc_hdlc->tx_descs);
> > + qmc_hdlc->netdev->netdev_ops = &qmc_hdlc_netdev_ops;
> > + ret = register_hdlc_device(qmc_hdlc->netdev);
> > + if (ret) {
> > + dev_err(qmc_hdlc->dev, "failed to register hdlc device (%d)\n", ret);
> > + goto free_netdev;
> > + }
> > +
> > + platform_set_drvdata(pdev, qmc_hdlc);
> > +
> > + return 0;
> > +
> > +free_netdev:
> > + free_netdev(qmc_hdlc->netdev);
> > + return ret;
> > +}
>
>
Thanks for the review.
Hervé
On Thu, Feb 22, 2024 at 05:45:01PM +0100, Herve Codina wrote:
> On Thu, 22 Feb 2024 17:29:05 +0200
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > On Thu, Feb 22, 2024 at 03:22:14PM +0100, Herve Codina wrote:
..
> > > + spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
> >
> > Why not using cleanup.h from day 1?
>
> I don't know about cleanup.h.
> Can you tell me more ?
> How should I use it ?
>
> > > +end:
> >
> > This label, in particular, will not be needed with above in place.
> >
> > > + spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
> > > + return ret;
> > > +}
Here are the examples:
6191e49de389 ("pinctrl: baytrail: Simplify code with cleanup helpers")
1d1b4770d4b6 ("platform/x86/intel/vsec: Use cleanup.h")
e2eeddefb046 ("pstore: inode: Convert mutex usage to guard(mutex)")
Some advanced stuff:
ced085ef369a ("PCI: Introduce cleanup helpers for device reference counts and locks")
Hope this helps.
Andy, Jakub,
On Thu, 22 Feb 2024 18:56:26 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> On Thu, Feb 22, 2024 at 05:45:01PM +0100, Herve Codina wrote:
> > On Thu, 22 Feb 2024 17:29:05 +0200
> > Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > > On Thu, Feb 22, 2024 at 03:22:14PM +0100, Herve Codina wrote:
>
> ...
>
> > > > + spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
> > >
> > > Why not using cleanup.h from day 1?
> >
> > I don't know about cleanup.h.
> > Can you tell me more ?
> > How should I use it ?
> >
> > > > +end:
> > >
> > > This label, in particular, will not be needed with above in place.
> > >
> > > > + spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
> > > > + return ret;
> > > > +}
>
> Here are the examples:
> 6191e49de389 ("pinctrl: baytrail: Simplify code with cleanup helpers")
> 1d1b4770d4b6 ("platform/x86/intel/vsec: Use cleanup.h")
> e2eeddefb046 ("pstore: inode: Convert mutex usage to guard(mutex)")
>
> Some advanced stuff:
> ced085ef369a ("PCI: Introduce cleanup helpers for device reference counts and locks")
>
> Hope this helps.
Sure, thanks for the pointer.
Jakub,
nothing in drivers/net seems to use the guard() (from cleanup.h) family
macro.
Are you ok with having this HDLC driver that uses guard() macros ?
Best regards,
Hervé
@@ -197,6 +197,18 @@ config FARSYNC
To compile this driver as a module, choose M here: the
module will be called farsync.
+config FSL_QMC_HDLC
+ tristate "Freescale QMC HDLC support"
+ depends on HDLC
+ depends on CPM_QMC
+ help
+ HDLC support using the Freescale QUICC Multichannel Controller (QMC).
+
+ To compile this driver as a module, choose M here: the
+ module will be called fsl_qmc_hdlc.
+
+ If unsure, say N.
+
config FSL_UCC_HDLC
tristate "Freescale QUICC Engine HDLC support"
depends on HDLC
@@ -25,6 +25,7 @@ obj-$(CONFIG_WANXL) += wanxl.o
obj-$(CONFIG_PCI200SYN) += pci200syn.o
obj-$(CONFIG_PC300TOO) += pc300too.o
obj-$(CONFIG_IXP4XX_HSS) += ixp4xx_hss.o
+obj-$(CONFIG_FSL_QMC_HDLC) += fsl_qmc_hdlc.o
obj-$(CONFIG_FSL_UCC_HDLC) += fsl_ucc_hdlc.o
obj-$(CONFIG_SLIC_DS26522) += slic_ds26522.o
new file mode 100644
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Freescale QMC HDLC Device Driver
+ *
+ * Copyright 2023 CS GROUP France
+ *
+ * Author: Herve Codina <herve.codina@bootlin.com>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/hdlc.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <soc/fsl/qe/qmc.h>
+
+struct qmc_hdlc_desc {
+ struct net_device *netdev;
+ struct sk_buff *skb; /* NULL if the descriptor is not in use */
+ dma_addr_t dma_addr;
+ size_t dma_size;
+};
+
+struct qmc_hdlc {
+ struct device *dev;
+ struct qmc_chan *qmc_chan;
+ struct net_device *netdev;
+ bool is_crc32;
+ spinlock_t tx_lock; /* Protect tx descriptors */
+ struct qmc_hdlc_desc tx_descs[8];
+ unsigned int tx_out;
+ struct qmc_hdlc_desc rx_descs[4];
+};
+
+static struct qmc_hdlc *netdev_to_qmc_hdlc(struct net_device *netdev)
+{
+ return dev_to_hdlc(netdev)->priv;
+}
+
+static int qmc_hdlc_recv_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc, size_t size);
+
+#define QMC_HDLC_RX_ERROR_FLAGS (QMC_RX_FLAG_HDLC_OVF | \
+ QMC_RX_FLAG_HDLC_UNA | \
+ QMC_RX_FLAG_HDLC_ABORT | \
+ QMC_RX_FLAG_HDLC_CRC)
+
+static void qmc_hcld_recv_complete(void *context, size_t length, unsigned int flags)
+{
+ struct qmc_hdlc_desc *desc = context;
+ struct net_device *netdev = desc->netdev;
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+ int ret;
+
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_FROM_DEVICE);
+
+ if (flags & QMC_HDLC_RX_ERROR_FLAGS) {
+ netdev->stats.rx_errors++;
+ if (flags & QMC_RX_FLAG_HDLC_OVF) /* Data overflow */
+ netdev->stats.rx_over_errors++;
+ if (flags & QMC_RX_FLAG_HDLC_UNA) /* bits received not multiple of 8 */
+ netdev->stats.rx_frame_errors++;
+ if (flags & QMC_RX_FLAG_HDLC_ABORT) /* Received an abort sequence */
+ netdev->stats.rx_frame_errors++;
+ if (flags & QMC_RX_FLAG_HDLC_CRC) /* CRC error */
+ netdev->stats.rx_crc_errors++;
+ kfree_skb(desc->skb);
+ } else {
+ netdev->stats.rx_packets++;
+ netdev->stats.rx_bytes += length;
+
+ skb_put(desc->skb, length);
+ desc->skb->protocol = hdlc_type_trans(desc->skb, netdev);
+ netif_rx(desc->skb);
+ }
+
+ /* Re-queue a transfer using the same descriptor */
+ ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, desc->dma_size);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "queue recv desc failed (%d)\n", ret);
+ netdev->stats.rx_errors++;
+ }
+}
+
+static int qmc_hdlc_recv_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc, size_t size)
+{
+ int ret;
+
+ desc->skb = dev_alloc_skb(size);
+ if (!desc->skb)
+ return -ENOMEM;
+
+ desc->dma_size = size;
+ desc->dma_addr = dma_map_single(qmc_hdlc->dev, desc->skb->data,
+ desc->dma_size, DMA_FROM_DEVICE);
+ ret = dma_mapping_error(qmc_hdlc->dev, desc->dma_addr);
+ if (ret)
+ goto free_skb;
+
+ ret = qmc_chan_read_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
+ qmc_hcld_recv_complete, desc);
+ if (ret)
+ goto dma_unmap;
+
+ return 0;
+
+dma_unmap:
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_FROM_DEVICE);
+free_skb:
+ kfree_skb(desc->skb);
+ desc->skb = NULL;
+ return ret;
+}
+
+static void qmc_hdlc_xmit_complete(void *context)
+{
+ struct qmc_hdlc_desc *desc = context;
+ struct net_device *netdev = desc->netdev;
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+ struct sk_buff *skb;
+ unsigned long flags;
+
+ spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
+ skb = desc->skb;
+ desc->skb = NULL; /* Release the descriptor */
+ if (netif_queue_stopped(netdev))
+ netif_wake_queue(netdev);
+ spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
+
+ netdev->stats.tx_packets++;
+ netdev->stats.tx_bytes += skb->len;
+
+ dev_consume_skb_any(skb);
+}
+
+static int qmc_hdlc_xmit_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc)
+{
+ int ret;
+
+ desc->dma_addr = dma_map_single(qmc_hdlc->dev, desc->skb->data,
+ desc->dma_size, DMA_TO_DEVICE);
+ ret = dma_mapping_error(qmc_hdlc->dev, desc->dma_addr);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "failed to map skb\n");
+ return ret;
+ }
+
+ ret = qmc_chan_write_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
+ qmc_hdlc_xmit_complete, desc);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "qmc chan write returns %d\n", ret);
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
+ return ret;
+ }
+
+ return 0;
+}
+
+static netdev_tx_t qmc_hdlc_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+ struct qmc_hdlc_desc *desc;
+ unsigned long flags;
+ int err;
+ int ret;
+
+ spin_lock_irqsave(&qmc_hdlc->tx_lock, flags);
+
+ desc = &qmc_hdlc->tx_descs[qmc_hdlc->tx_out];
+ if (WARN_ONCE(desc->skb, "No tx descriptors available\n")) {
+ /* Should never happen.
+ * Previous xmit should have already stopped the queue.
+ */
+ netif_stop_queue(netdev);
+ ret = NETDEV_TX_BUSY;
+ goto end;
+ }
+
+ desc->netdev = netdev;
+ desc->dma_size = skb->len;
+ desc->skb = skb;
+ err = qmc_hdlc_xmit_queue(qmc_hdlc, desc);
+ if (err) {
+ desc->skb = NULL; /* Release the descriptor */
+ if (err == -EBUSY) {
+ netif_stop_queue(netdev);
+ ret = NETDEV_TX_BUSY;
+ goto end;
+ }
+ dev_kfree_skb(skb);
+ netdev->stats.tx_dropped++;
+ ret = NETDEV_TX_OK;
+ goto end;
+ }
+
+ qmc_hdlc->tx_out = (qmc_hdlc->tx_out + 1) % ARRAY_SIZE(qmc_hdlc->tx_descs);
+
+ if (qmc_hdlc->tx_descs[qmc_hdlc->tx_out].skb)
+ netif_stop_queue(netdev);
+
+ ret = NETDEV_TX_OK;
+end:
+ spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags);
+ return ret;
+}
+
+static int qmc_hdlc_open(struct net_device *netdev)
+{
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+ struct qmc_chan_param chan_param;
+ struct qmc_hdlc_desc *desc;
+ int ret;
+ int i;
+
+ ret = hdlc_open(netdev);
+ if (ret)
+ return ret;
+
+ chan_param.mode = QMC_HDLC;
+ /* HDLC_MAX_MRU + 4 for the CRC
+ * HDLC_MAX_MRU + 4 + 8 for the CRC and some extraspace needed by the QMC
+ */
+ chan_param.hdlc.max_rx_buf_size = HDLC_MAX_MRU + 4 + 8;
+ chan_param.hdlc.max_rx_frame_size = HDLC_MAX_MRU + 4;
+ chan_param.hdlc.is_crc32 = qmc_hdlc->is_crc32;
+ ret = qmc_chan_set_param(qmc_hdlc->qmc_chan, &chan_param);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "failed to set param (%d)\n", ret);
+ goto hdlc_close;
+ }
+
+ /* Queue as many recv descriptors as possible */
+ for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
+ desc = &qmc_hdlc->rx_descs[i];
+
+ desc->netdev = netdev;
+ ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, chan_param.hdlc.max_rx_buf_size);
+ if (ret) {
+ if (ret == -EBUSY && i != 0)
+ break; /* We use all the QMC chan capability */
+ goto free_desc;
+ }
+ }
+
+ ret = qmc_chan_start(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "qmc chan start failed (%d)\n", ret);
+ goto free_desc;
+ }
+
+ netif_start_queue(netdev);
+
+ return 0;
+
+free_desc:
+ qmc_chan_reset(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
+ for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
+ desc = &qmc_hdlc->rx_descs[i];
+ if (!desc->skb)
+ continue;
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
+ DMA_FROM_DEVICE);
+ kfree_skb(desc->skb);
+ desc->skb = NULL;
+ }
+hdlc_close:
+ hdlc_close(netdev);
+ return ret;
+}
+
+static int qmc_hdlc_close(struct net_device *netdev)
+{
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+ struct qmc_hdlc_desc *desc;
+ int i;
+
+ qmc_chan_stop(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
+ qmc_chan_reset(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
+
+ netif_stop_queue(netdev);
+
+ for (i = 0; i < ARRAY_SIZE(qmc_hdlc->tx_descs); i++) {
+ desc = &qmc_hdlc->tx_descs[i];
+ if (!desc->skb)
+ continue;
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
+ DMA_TO_DEVICE);
+ kfree_skb(desc->skb);
+ desc->skb = NULL;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
+ desc = &qmc_hdlc->rx_descs[i];
+ if (!desc->skb)
+ continue;
+ dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
+ DMA_FROM_DEVICE);
+ kfree_skb(desc->skb);
+ desc->skb = NULL;
+ }
+
+ hdlc_close(netdev);
+ return 0;
+}
+
+static int qmc_hdlc_attach(struct net_device *netdev, unsigned short encoding,
+ unsigned short parity)
+{
+ struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
+
+ if (encoding != ENCODING_NRZ)
+ return -EINVAL;
+
+ switch (parity) {
+ case PARITY_CRC16_PR1_CCITT:
+ qmc_hdlc->is_crc32 = false;
+ break;
+ case PARITY_CRC32_PR1_CCITT:
+ qmc_hdlc->is_crc32 = true;
+ break;
+ default:
+ dev_err(qmc_hdlc->dev, "unsupported parity %u\n", parity);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const struct net_device_ops qmc_hdlc_netdev_ops = {
+ .ndo_open = qmc_hdlc_open,
+ .ndo_stop = qmc_hdlc_close,
+ .ndo_start_xmit = hdlc_start_xmit,
+ .ndo_siocwandev = hdlc_ioctl,
+};
+
+static int qmc_hdlc_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct qmc_hdlc *qmc_hdlc;
+ struct qmc_chan_info info;
+ hdlc_device *hdlc;
+ int ret;
+
+ qmc_hdlc = devm_kzalloc(&pdev->dev, sizeof(*qmc_hdlc), GFP_KERNEL);
+ if (!qmc_hdlc)
+ return -ENOMEM;
+
+ qmc_hdlc->dev = &pdev->dev;
+ spin_lock_init(&qmc_hdlc->tx_lock);
+
+ qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(qmc_hdlc->dev, np);
+ if (IS_ERR(qmc_hdlc->qmc_chan)) {
+ ret = PTR_ERR(qmc_hdlc->qmc_chan);
+ return dev_err_probe(qmc_hdlc->dev, ret, "get QMC channel failed\n");
+ }
+
+ ret = qmc_chan_get_info(qmc_hdlc->qmc_chan, &info);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "get QMC channel info failed %d\n", ret);
+ return ret;
+ }
+
+ if (info.mode != QMC_HDLC) {
+ dev_err(qmc_hdlc->dev, "QMC chan mode %d is not QMC_HDLC\n",
+ info.mode);
+ return -EINVAL;
+ }
+
+ qmc_hdlc->netdev = alloc_hdlcdev(qmc_hdlc);
+ if (!qmc_hdlc->netdev) {
+ dev_err(qmc_hdlc->dev, "failed to alloc hdlc dev\n");
+ return -ENOMEM;
+ }
+
+ hdlc = dev_to_hdlc(qmc_hdlc->netdev);
+ hdlc->attach = qmc_hdlc_attach;
+ hdlc->xmit = qmc_hdlc_xmit;
+ SET_NETDEV_DEV(qmc_hdlc->netdev, qmc_hdlc->dev);
+ qmc_hdlc->netdev->tx_queue_len = ARRAY_SIZE(qmc_hdlc->tx_descs);
+ qmc_hdlc->netdev->netdev_ops = &qmc_hdlc_netdev_ops;
+ ret = register_hdlc_device(qmc_hdlc->netdev);
+ if (ret) {
+ dev_err(qmc_hdlc->dev, "failed to register hdlc device (%d)\n", ret);
+ goto free_netdev;
+ }
+
+ platform_set_drvdata(pdev, qmc_hdlc);
+
+ return 0;
+
+free_netdev:
+ free_netdev(qmc_hdlc->netdev);
+ return ret;
+}
+
+static int qmc_hdlc_remove(struct platform_device *pdev)
+{
+ struct qmc_hdlc *qmc_hdlc = platform_get_drvdata(pdev);
+
+ unregister_hdlc_device(qmc_hdlc->netdev);
+ free_netdev(qmc_hdlc->netdev);
+
+ return 0;
+}
+
+static const struct of_device_id qmc_hdlc_id_table[] = {
+ { .compatible = "fsl,qmc-hdlc" },
+ {} /* sentinel */
+};
+MODULE_DEVICE_TABLE(of, qmc_hdlc_driver);
+
+static struct platform_driver qmc_hdlc_driver = {
+ .driver = {
+ .name = "fsl-qmc-hdlc",
+ .of_match_table = qmc_hdlc_id_table,
+ },
+ .probe = qmc_hdlc_probe,
+ .remove = qmc_hdlc_remove,
+};
+module_platform_driver(qmc_hdlc_driver);
+
+MODULE_AUTHOR("Herve Codina <herve.codina@bootlin.com>");
+MODULE_DESCRIPTION("QMC HDLC driver");
+MODULE_LICENSE("GPL");