On 28-08-23, 19:00, Martin Povišer wrote:
> Add a dmaengine driver for the Apple SIO coprocessor found on Apple
> SoCs where it provides DMA services. Have the driver support cyclic
> transactions so that ALSA drivers can rely on it in audio output to
> HDMI and DisplayPort.
>
> Signed-off-by: Martin Povišer <povik+lin@xxxxxxxxxxx>
> ---
> MAINTAINERS | 2 +
> drivers/dma/Kconfig | 11 +
> drivers/dma/Makefile | 1 +
> drivers/dma/apple-sio.c | 868 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 882 insertions(+)
> create mode 100644 drivers/dma/apple-sio.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3be1bdfe8ecc..e65cf3d535ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1865,7 +1865,9 @@ M: Martin Povišer <povik+lin@xxxxxxxxxxx>
> L: asahi@xxxxxxxxxxxxxxx
> L: alsa-devel@xxxxxxxxxxxxxxxx (moderated for non-subscribers)
> S: Maintained
> +F: Documentation/devicetree/bindings/dma/apple,sio.yaml
> F: Documentation/devicetree/bindings/sound/apple,*
> +F: drivers/dma/apple-sio.c
> F: sound/soc/apple/*
> F: sound/soc/codecs/cs42l83-i2c.c
>
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index f52d36e713f3..6e385dee2d3d 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -89,10 +89,21 @@ config APPLE_ADMAC
> tristate "Apple ADMAC support"
> depends on ARCH_APPLE || COMPILE_TEST
> select DMA_ENGINE
> + select DMA_VIRTUAL_CHANNELS
> default ARCH_APPLE
> help
> Enable support for Audio DMA Controller found on Apple Silicon SoCs.
>
> +config APPLE_SIO
> + tristate "Apple SIO support"
> + depends on ARCH_APPLE || COMPILE_TEST
> + depends on APPLE_RTKIT
> + select DMA_ENGINE
> + default ARCH_APPLE
> + help
> + Enable support for the SIO coprocessor found on Apple Silicon SoCs
> + where it provides DMA services.
> +
> config AT_HDMAC
> tristate "Atmel AHB DMA support"
> depends on ARCH_AT91
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 83553a97a010..787583ff2d45 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
> obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
> obj-$(CONFIG_AMD_PTDMA) += ptdma/
> obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
> +obj-$(CONFIG_APPLE_SIO) += apple-sio.o
> obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
> obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
> obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
> diff --git a/drivers/dma/apple-sio.c b/drivers/dma/apple-sio.c
> new file mode 100644
> index 000000000000..e15deeded4dc
> --- /dev/null
> +++ b/drivers/dma/apple-sio.c
> @@ -0,0 +1,868 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Driver for SIO coprocessor on t8103 (M1) and other Apple SoCs
> + *
> + * Copyright (C) The Asahi Linux Contributors
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/completion.h>
> +#include <linux/device.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_dma.h>
> +#include <linux/soc/apple/rtkit.h>
> +
> +#include "dmaengine.h"
> +#include "virt-dma.h"
> +
> +#define NCHANNELS_MAX 0x80
> +
> +#define REG_CPU_CONTROL 0x44
> +#define CPU_CONTROL_RUN BIT(4)
> +
> +#define SIOMSG_DATA GENMASK(63, 32)
> +#define SIOMSG_TYPE GENMASK(23, 16)
> +#define SIOMSG_PARAM GENMASK(31, 24)
> +#define SIOMSG_TAG GENMASK(13, 8)
> +#define SIOMSG_EP GENMASK(7, 0)
> +
> +#define EP_SIO 0x20
> +
> +#define MSG_START 0x2
> +#define MSG_SETUP 0x3
> +#define MSG_CONFIGURE 0x5
> +#define MSG_ISSUE 0x6
> +#define MSG_TERMINATE 0x8
> +#define MSG_ACK 0x65
> +#define MSG_NACK 0x66
> +#define MSG_STARTED 0x67
> +#define MSG_REPORT 0x68
> +
> +#define SIO_CALL_TIMEOUT_MS 100
> +#define SIO_SHMEM_SIZE 0x1000
> +#define SIO_NO_DESC_SLOTS 64
> +
> +/*
> + * There are two kinds of 'transaction descriptors' in play here.
> + *
> + * There's the struct sio_tx, and the struct dma_async_tx_descriptor embedded
> + * inside, which jointly represent a transaction to the dmaengine subsystem.
> + * At this time we only support those transactions to be cyclic.
> + *
> + * Then there are the coprocessor descriptors, which is what the coprocessor
> + * knows and understands. These don't seem to have a cyclic regime, so we can't
> + * map the dmaengine transaction on an exact coprocessor counterpart. Instead
> + * we continually queue up many coprocessor descriptors to implement a cyclic
> + * transaction.
> + *
> + * The number below is the maximum of how far ahead (how many) coprocessor
> + * descriptors we should be queuing up, per channel, for a cyclic transaction.
> + * Basically it's a made-up number.
> + */
> +#define SIO_MAX_NINFLIGHT 4
you meant SIO_MAX_INFLIGHT if not what is NINFLIGHT?
> +struct sio_coproc_desc {
> + u32 pad1;
> + u32 flag;
> + u64 unk;
> + u64 iova;
> + u64 size;
> + u64 pad2;
> + u64 pad3;
> +} __packed;
> +static_assert(sizeof(struct sio_coproc_desc) == 48);
> +
> +struct sio_shmem_chan_config {
> + u32 datashape;
> + u32 timeout;
> + u32 fifo;
> + u32 threshold;
> + u32 limit;
> +} __packed;
> +
> +struct sio_data;
> +struct sio_tx;
> +
> +struct sio_chan {
> + unsigned int no;
> + struct sio_data *host;
> + struct virt_dma_chan vc;
> + struct work_struct terminate_wq;
> +
> + struct sio_tx *current_tx;
> +};
> +
> +#define SIO_NTAGS 16
> +
> +typedef void (*sio_ack_callback)(struct sio_chan *, void *, bool);
what is this callback used for?
> +
> +struct sio_data {
> + void __iomem *base;
> + struct dma_device dma;
> + struct device *dev;
> + struct apple_rtkit *rtk;
> + void *shmem;
> + struct sio_coproc_desc *shmem_desc_base;
> + unsigned long *desc_allocated;
> +
> + struct sio_tagdata {
> + DECLARE_BITMAP(allocated, SIO_NTAGS);
> + int last_tag;
> +
> + struct completion completions[SIO_NTAGS];
> + bool atomic[SIO_NTAGS];
> + bool acked[SIO_NTAGS];
> +
> + sio_ack_callback ack_callback[SIO_NTAGS];
> + void *cookie[SIO_NTAGS];
> + } tags;
> +
> + int nchannels;
> + struct sio_chan channels[];
> +};
> +
> +struct sio_tx {
> + struct virt_dma_desc vd;
> + struct completion done;
> +
> + bool terminated;
> + size_t period_len;
> + int nperiods;
> + int ninflight;
> + int next;
> +
> + struct sio_coproc_desc *siodesc[];
> +};
> +
> +static int sio_send_siomsg(struct sio_data *sio, u64 msg);
> +static int sio_send_siomsg_atomic(struct sio_data *sio, u64 msg,
> + sio_ack_callback ack_callback,
> + void *cookie);
> +static int sio_call(struct sio_data *sio, u64 msg);
> +
> +static struct sio_chan *to_sio_chan(struct dma_chan *chan)
> +{
> + return container_of(chan, struct sio_chan, vc.chan);
> +}
> +
> +static struct sio_tx *to_sio_tx(struct dma_async_tx_descriptor *tx)
> +{
> + return container_of(tx, struct sio_tx, vd.tx);
> +}
> +
> +static int sio_alloc_tag(struct sio_data *sio)
> +{
> + struct sio_tagdata *tags = &sio->tags;
> + int tag, i;
> +
> + /*
> + * Because tag number 0 is special, the usable tag range
> + * is 1...(SIO_NTAGS - 1). So, to pick the next usable tag,
> + * we do modulo (SIO_NTAGS - 1) *then* plus one.
> + */
> +
> +#define SIO_USABLE_TAGS (SIO_NTAGS - 1)
> + tag = (READ_ONCE(tags->last_tag) % SIO_USABLE_TAGS) + 1;
> +
> + for (i = 0; i < SIO_USABLE_TAGS; i++) {
> + if (!test_and_set_bit(tag, tags->allocated))
> + break;
> +
> + tag = (tag % SIO_USABLE_TAGS) + 1;
> + }
> +
> + WRITE_ONCE(tags->last_tag, tag);
> +
> + if (i < SIO_USABLE_TAGS)
> + return tag;
> + else
> + return -EBUSY;
> +#undef SIO_USABLE_TAGS
ida_alloc can be used as well to get a tag as well
> +}
> +
> +static void sio_free_tag(struct sio_data *sio, int tag)
> +{
> + struct sio_tagdata *tags = &sio->tags;
> +
> + if (WARN_ON(tag >= SIO_NTAGS))
> + return;
> +
> + tags->atomic[tag] = false;
> + tags->ack_callback[tag] = NULL;
> +
> + WARN_ON(!test_and_clear_bit(tag, tags->allocated));
> +}
> +
> +static void sio_set_tag_atomic(struct sio_data *sio, int tag,
> + sio_ack_callback ack_callback,
> + void *cookie)
> +{
> + struct sio_tagdata *tags = &sio->tags;
> +
> + tags->atomic[tag] = true;
> + tags->ack_callback[tag] = ack_callback;
> + tags->cookie[tag] = cookie;
> +}
> +
> +static struct sio_coproc_desc *sio_alloc_desc(struct sio_data *sio)
> +{
> + int i;
> +
> + for (i = 0; i < SIO_NO_DESC_SLOTS; i++)
> + if (!test_and_set_bit(i, sio->desc_allocated))
> + return sio->shmem_desc_base + i;
> +
> + return NULL;
> +}
> +
> +static void sio_free_desc(struct sio_data *sio, struct sio_coproc_desc *desc)
> +{
> + clear_bit(desc - sio->shmem_desc_base, sio->desc_allocated);
> +}
> +
> +static int sio_coproc_desc_slot(struct sio_data *sio, struct sio_coproc_desc *desc)
> +{
> + return (desc - sio->shmem_desc_base) * 4;
> +}
> +
> +static enum dma_transfer_direction sio_chan_direction(int channo)
> +{
> + /* Channel directions are fixed based on channel number */
> + return (channo & 1) ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
> +}
> +
> +static void sio_tx_free(struct virt_dma_desc *vd)
> +{
> + struct sio_data *sio = to_sio_chan(vd->tx.chan)->host;
> + struct sio_tx *siotx = to_sio_tx(&vd->tx);
> + int i;
> +
> + for (i = 0; i < siotx->nperiods; i++)
> + if (siotx->siodesc[i])
> + sio_free_desc(sio, siotx->siodesc[i]);
> + kfree(siotx);
> +}
> +
> +static struct dma_async_tx_descriptor *sio_prep_dma_cyclic(
> + struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
> + size_t period_len, enum dma_transfer_direction direction,
> + unsigned long flags)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> + struct sio_tx *siotx = NULL;
> + int i, nperiods = buf_len / period_len;
> +
> + if (direction != sio_chan_direction(siochan->no))
> + return NULL;
> +
> + siotx = kzalloc(struct_size(siotx, siodesc, nperiods), GFP_NOWAIT);
wasnt there a helper to do this sort of thing...
> + if (!siotx)
> + return NULL;
> +
> + init_completion(&siotx->done);
> + siotx->period_len = period_len;
> + siotx->nperiods = nperiods;
> +
> + for (i = 0; i < nperiods; i++) {
> + struct sio_coproc_desc *d;
> +
> + siotx->siodesc[i] = d = sio_alloc_desc(siochan->host);
> + if (!d) {
> + sio_tx_free(&siotx->vd);
> + return NULL;
> + }
> +
> + d->flag = 1; // not sure what's up with this
:-) but /* comments only */ pls
> + d->iova = buf_addr + period_len * i;
> + d->size = period_len;
> + }
> + dma_wmb();
why do you need a barrier here
> +
> + return vchan_tx_prep(&siochan->vc, &siotx->vd, flags);
> +}
> +
> +static enum dma_status sio_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> + struct virt_dma_desc *vd;
> + struct sio_tx *siotx;
> + enum dma_status ret;
> + unsigned long flags;
> + int periods_residue;
> + size_t residue;
> +
> + ret = dma_cookie_status(chan, cookie, txstate);
> + if (ret == DMA_COMPLETE || !txstate)
> + return ret;
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + siotx = siochan->current_tx;
> +
> + if (siotx && siotx->vd.tx.cookie == cookie) {
> + ret = DMA_IN_PROGRESS;
> + periods_residue = siotx->next - siotx->ninflight;
> + while (periods_residue < 0)
> + periods_residue += siotx->nperiods;
> + residue = (siotx->nperiods - periods_residue) * siotx->period_len;
> + } else {
> + ret = DMA_IN_PROGRESS;
> + residue = 0;
> + vd = vchan_find_desc(&siochan->vc, cookie);
> + if (vd) {
> + siotx = to_sio_tx(&vd->tx);
> + residue = siotx->period_len * siotx->nperiods;
> + }
> + }
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> + dma_set_residue(txstate, residue);
> +
> + return ret;
> +}
> +
> +static bool sio_fill_in_locked(struct sio_chan *siochan);
> +
> +static void sio_handle_issue_ack(struct sio_chan *siochan, void *cookie, bool ok)
> +{
> + unsigned long flags;
> + dma_cookie_t tx_cookie = (unsigned long) cookie;
> + struct sio_tx *tx;
reverse christmas tree style pls
> +
> + if (!ok) {
> + dev_err(siochan->host->dev, "nacked issue on chan %d\n", siochan->no);
> + return;
> + }
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + if (!siochan->current_tx || tx_cookie != siochan->current_tx->vd.tx.cookie ||
> + siochan->current_tx->terminated)
> + goto out;
> +
> + tx = siochan->current_tx;
> + tx->next = (tx->next + 1) % tx->nperiods;
> + tx->ninflight++;
> + sio_fill_in_locked(siochan);
> +
> +out:
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +}
> +
> +static bool sio_fill_in_locked(struct sio_chan *siochan)
> +{
> + struct sio_data *sio = siochan->host;
> + struct sio_tx *tx = siochan->current_tx;
> + struct sio_coproc_desc *d = tx->siodesc[tx->next];
> + int ret;
> +
> + if (tx->ninflight >= SIO_MAX_NINFLIGHT || tx->terminated)
> + return false;
> +
> + static_assert(sizeof(dma_cookie_t) <= sizeof(void *));
> + ret = sio_send_siomsg_atomic(sio, FIELD_PREP(SIOMSG_EP, siochan->no) |
> + FIELD_PREP(SIOMSG_TYPE, MSG_ISSUE) |
> + FIELD_PREP(SIOMSG_DATA, sio_coproc_desc_slot(sio, d)),
> + sio_handle_issue_ack, (void *) (uintptr_t) tx->vd.tx.cookie);
> + if (ret < 0)
> + dev_err_ratelimited(sio->dev, "can't issue on chan %d ninflight %d: %d\n",
> + siochan->no, tx->ninflight, ret);
> + return true;
> +}
> +
> +static void sio_update_current_tx_locked(struct sio_chan *siochan)
> +{
> + struct virt_dma_desc *vd = vchan_next_desc(&siochan->vc);
> +
> + if (vd && !siochan->current_tx) {
> + list_del(&vd->node);
> + siochan->current_tx = to_sio_tx(&vd->tx);
> + sio_fill_in_locked(siochan);
> + }
> +}
> +
> +static void sio_issue_pending(struct dma_chan *chan)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + vchan_issue_pending(&siochan->vc);
> + sio_update_current_tx_locked(siochan);
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +}
> +
> +static int sio_terminate_all(struct dma_chan *chan)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> + unsigned long flags;
> + LIST_HEAD(to_free);
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + if (siochan->current_tx && !siochan->current_tx->terminated) {
> + dma_cookie_complete(&siochan->current_tx->vd.tx);
> + siochan->current_tx->terminated = true;
> + schedule_work(&siochan->terminate_wq);
> + }
> + vchan_get_all_descriptors(&siochan->vc, &to_free);
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +
> + vchan_dma_desc_free_list(&siochan->vc, &to_free);
> +
> + return 0;
> +}
> +
> +static void sio_terminate_work(struct work_struct *wq)
> +{
> + struct sio_chan *siochan = container_of(wq, struct sio_chan, terminate_wq);
> + struct sio_tx *tx;
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + tx = siochan->current_tx;
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +
> + if (WARN_ON(!tx))
> + return;
> +
> + ret = sio_call(siochan->host, FIELD_PREP(SIOMSG_EP, siochan->no) |
> + FIELD_PREP(SIOMSG_TYPE, MSG_TERMINATE));
> + if (ret < 0)
> + dev_err(siochan->host->dev, "terminate call on chan %d failed: %d\n",
> + siochan->no, ret);
> +
> + ret = wait_for_completion_timeout(&tx->done, msecs_to_jiffies(500));
> + if (!ret)
> + dev_err(siochan->host->dev, "terminate descriptor wait timed out\n");
> +
> + tasklet_kill(&siochan->vc.task);
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + WARN_ON(siochan->current_tx != tx);
> + siochan->current_tx = NULL;
> + sio_update_current_tx_locked(siochan);
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +
> + sio_tx_free(&tx->vd);
> +}
> +
> +static void sio_synchronize(struct dma_chan *chan)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> +
> + flush_work(&siochan->terminate_wq);
> +}
> +
> +static void sio_free_chan_resources(struct dma_chan *chan)
> +{
> + sio_terminate_all(chan);
> + sio_synchronize(chan);
> + vchan_free_chan_resources(&to_sio_chan(chan)->vc);
> +}
> +
> +static struct dma_chan *sio_dma_of_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct sio_data *sio = (struct sio_data *) ofdma->of_dma_data;
> + unsigned int index = dma_spec->args[0];
> +
> + if (dma_spec->args_count != 1 || index >= sio->nchannels)
> + return ERR_PTR(-EINVAL);
> +
> + return dma_get_slave_channel(&sio->channels[index].vc.chan);
> +}
> +
> +static void sio_rtk_crashed(void *cookie)
> +{
> + struct sio_data *sio = cookie;
> +
> + dev_err(sio->dev, "SIO down (crashed)");
> +}
> +
> +static void sio_process_report(struct sio_chan *siochan)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&siochan->vc.lock, flags);
> + if (siochan->current_tx) {
> + struct sio_tx *tx = siochan->current_tx;
> +
> + if (tx->ninflight)
> + tx->ninflight--;
> + vchan_cyclic_callback(&tx->vd);
> + if (!sio_fill_in_locked(siochan) && !tx->ninflight)
> + complete(&tx->done);
> + }
> + spin_unlock_irqrestore(&siochan->vc.lock, flags);
> +}
> +
> +static void sio_recv_msg(void *cookie, u8 ep, u64 msg)
> +{
> + struct sio_data *sio = cookie;
> + struct sio_tagdata *tags = &sio->tags;
> + u32 data;
> + u8 param, type, tag, sioep;
> +
> + if (ep != EP_SIO)
> + goto unknown;
> +
> + data = FIELD_GET(SIOMSG_DATA, msg);
> + param = FIELD_GET(SIOMSG_PARAM, msg);
> + type = FIELD_GET(SIOMSG_TYPE, msg);
> + tag = FIELD_GET(SIOMSG_TAG, msg);
> + sioep = FIELD_GET(SIOMSG_EP, msg);
> +
> + switch (type) {
> + case MSG_STARTED:
> + dev_info(sio->dev, "SIO protocol v%u\n", data);
> + type = MSG_ACK; /* Pretend this is an ACK */
> + fallthrough;
> + case MSG_ACK:
> + case MSG_NACK:
> + if (WARN_ON(tag >= SIO_NTAGS))
> + break;
> +
> + if (tags->atomic[tag]) {
> + sio_ack_callback callback = tags->ack_callback[tag];
> +
> + if (callback && !WARN_ON(sioep >= sio->nchannels))
> + callback(&sio->channels[sioep],
> + tags->cookie[tag], type == MSG_ACK);
> + if (type == MSG_NACK)
> + dev_err(sio->dev, "got a NACK on channel %d\n", sioep);
> + sio_free_tag(sio, tag);
> + } else {
> + tags->acked[tag] = (type == MSG_ACK);
> + complete(&tags->completions[tag]);
> + }
> + break;
> +
> + case MSG_REPORT:
> + if (WARN_ON(sioep >= sio->nchannels))
> + break;
> +
> + sio_process_report(&sio->channels[sioep]);
> + break;
> +
> + default:
> + goto unknown;
> + }
> + return;
> +
> +unknown:
> + dev_warn(sio->dev, "received unknown message: ep %x data %016llx\n",
> + ep, msg);
> +}
> +
> +static int _sio_send_siomsg(struct sio_data *sio, u64 msg, bool atomic,
> + sio_ack_callback ack_callback, void *cookie)
> +{
> + int tag, ret;
> +
> + tag = sio_alloc_tag(sio);
> + if (tag < 0)
> + return tag;
> +
> + if (atomic)
> + sio_set_tag_atomic(sio, tag, ack_callback, cookie);
> + else
> + reinit_completion(&sio->tags.completions[tag]);
> +
> + msg &= ~SIOMSG_TAG;
> + msg |= FIELD_PREP(SIOMSG_TAG, tag);
> + ret = apple_rtkit_send_message(sio->rtk, EP_SIO, msg, NULL,
> + atomic);
> + if (ret < 0) {
> + sio_free_tag(sio, tag);
> + return ret;
> + }
> +
> + return tag;
> +}
> +
> +static int sio_send_siomsg(struct sio_data *sio, u64 msg)
> +{
> + return _sio_send_siomsg(sio, msg, false, NULL, NULL);
> +}
> +
> +static int sio_send_siomsg_atomic(struct sio_data *sio, u64 msg,
> + sio_ack_callback ack_callback,
> + void *cookie)
> +{
> + return _sio_send_siomsg(sio, msg, true, ack_callback, cookie);
> +}
> +
> +static int sio_call(struct sio_data *sio, u64 msg)
> +{
> + int tag, ret;
> +
> + tag = sio_send_siomsg(sio, msg);
> + if (tag < 0)
> + return tag;
> +
> + ret = wait_for_completion_timeout(&sio->tags.completions[tag],
> + msecs_to_jiffies(SIO_CALL_TIMEOUT_MS));
> + if (!ret) {
> + dev_warn(sio->dev, "call %8x timed out\n", msg);
> + sio_free_tag(sio, tag);
> + return -ETIME;
> + }
> +
> + ret = sio->tags.acked[tag];
> + sio_free_tag(sio, tag);
> +
> + return ret;
> +}
> +
> +static const struct apple_rtkit_ops sio_rtkit_ops = {
> + .crashed = sio_rtk_crashed,
> + .recv_message = sio_recv_msg,
> +};
so we ahve a remote processor which we send message to right?
> +static int sio_device_config(struct dma_chan *chan,
> + struct dma_slave_config *config)
> +{
> + struct sio_chan *siochan = to_sio_chan(chan);
> + struct sio_data *sio = siochan->host;
> + bool is_tx = sio_chan_direction(siochan->no) == DMA_MEM_TO_DEV;
> + struct sio_shmem_chan_config *cfg = sio->shmem;
> + int ret;
> +
> + switch (is_tx ? config->dst_addr_width : config->src_addr_width) {
> + case DMA_SLAVE_BUSWIDTH_1_BYTE:
> + cfg->datashape = 0;
> + break;
> + case DMA_SLAVE_BUSWIDTH_2_BYTES:
> + cfg->datashape = 1;
> + break;
> + case DMA_SLAVE_BUSWIDTH_4_BYTES:
> + cfg->datashape = 2;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + cfg->fifo = 0x800;
> + cfg->limit = 0x800;
> + cfg->threshold = 0x800;
> + dma_wmb();
??
> +
> + ret = sio_call(sio, FIELD_PREP(SIOMSG_TYPE, MSG_CONFIGURE) |
> + FIELD_PREP(SIOMSG_EP, siochan->no));
this does not sound okay, can you explain why this call is here
> +
> + if (ret == 1)
> + ret = 0;
> + else if (ret == 0)
> + ret = -EINVAL;
> + return ret;
> +}
> +
> +static int sio_alloc_shmem(struct sio_data *sio)
> +{
> + dma_addr_t iova;
> + int err;
> +
> + sio->shmem = dma_alloc_coherent(sio->dev, SIO_SHMEM_SIZE,
> + &iova, GFP_KERNEL);
> + if (!sio->shmem)
> + return -ENOMEM;
> +
> + sio->shmem_desc_base = (struct sio_coproc_desc *) (sio->shmem + 56);
> + sio->desc_allocated = devm_kzalloc(sio->dev, SIO_NO_DESC_SLOTS / 32,
> + GFP_KERNEL);
> + if (!sio->desc_allocated)
> + return -ENOMEM;
> +
> + err = sio_call(sio, FIELD_PREP(SIOMSG_TYPE, MSG_SETUP) |
> + FIELD_PREP(SIOMSG_PARAM, 1) |
> + FIELD_PREP(SIOMSG_DATA, iova >> 12));
> + if (err != 1) {
> + if (err == 0)
> + err = -EINVAL;
> + return err;
> + }
> +
> + err = sio_call(sio, FIELD_PREP(SIOMSG_TYPE, MSG_SETUP) |
> + FIELD_PREP(SIOMSG_PARAM, 2) |
> + FIELD_PREP(SIOMSG_DATA, SIO_SHMEM_SIZE));
> + if (err != 1) {
> + if (err == 0)
> + err = -EINVAL;
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static int sio_send_dt_params(struct sio_data *sio)
> +{
> + struct device_node *np = sio->dev->of_node;
> + const char *propname = "apple,sio-firmware-params";
> + int nparams, err, i;
> +
> + nparams = of_property_count_u32_elems(np, propname);
> + if (nparams < 0) {
> + err = nparams;
> + goto badprop;
> + }
> +
> + for (i = 0; i < nparams / 2; i++) {
> + u32 key, val;
> +
> + err = of_property_read_u32_index(np, propname, 2 * i, &key);
> + if (err)
> + goto badprop;
> + err = of_property_read_u32_index(np, propname, 2 * i + 1, &val);
> + if (err)
> + goto badprop;
> +
> + err = sio_call(sio, FIELD_PREP(SIOMSG_TYPE, MSG_SETUP) |
> + FIELD_PREP(SIOMSG_PARAM, key & 0xff) |
> + FIELD_PREP(SIOMSG_EP, key >> 8) |
> + FIELD_PREP(SIOMSG_DATA, val));
> + if (err < 1) {
> + if (err == 0)
> + err = -ENXIO;
> + return dev_err_probe(sio->dev, err, "sending SIO parameter %#x value %#x\n",
> + key, val);
> + }
> + }
> +
> + return 0;
> +
> +badprop:
> + return dev_err_probe(sio->dev, err, "failed to read '%s'\n", propname);
> +}
> +
> +static int sio_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct sio_data *sio;
> + struct dma_device *dma;
> + int nchannels;
> + int err, i;
> +
> + err = of_property_read_u32(np, "dma-channels", &nchannels);
> + if (err || nchannels > NCHANNELS_MAX)
> + return dev_err_probe(&pdev->dev, -EINVAL,
> + "missing or invalid dma-channels property\n");
> +
> + sio = devm_kzalloc(&pdev->dev, struct_size(sio, channels, nchannels), GFP_KERNEL);
> + if (!sio)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, sio);
> + sio->dev = &pdev->dev;
> + sio->nchannels = nchannels;
> +
> + sio->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(sio->base))
> + return PTR_ERR(sio->base);
> +
> + sio->rtk = devm_apple_rtkit_init(&pdev->dev, sio, NULL, 0, &sio_rtkit_ops);
> + if (IS_ERR(sio->rtk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(sio->rtk),
> + "couldn't initialize rtkit\n");
> + for (i = 1; i < SIO_NTAGS; i++)
> + init_completion(&sio->tags.completions[i]);
> +
> + dma = &sio->dma;
> + dma_cap_set(DMA_PRIVATE, dma->cap_mask);
> + dma_cap_set(DMA_CYCLIC, dma->cap_mask);
> +
> + dma->dev = &pdev->dev;
> + dma->device_free_chan_resources = sio_free_chan_resources;
> + dma->device_tx_status = sio_tx_status;
> + dma->device_issue_pending = sio_issue_pending;
> + dma->device_terminate_all = sio_terminate_all;
> + dma->device_synchronize = sio_synchronize;
> + dma->device_prep_dma_cyclic = sio_prep_dma_cyclic;
> + dma->device_config = sio_device_config;
> +
> + dma->directions = BIT(DMA_MEM_TO_DEV);
> + dma->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
> + dma->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
> + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
> + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
> +
> + INIT_LIST_HEAD(&dma->channels);
> + for (i = 0; i < nchannels; i++) {
> + struct sio_chan *siochan = &sio->channels[i];
> +
> + siochan->host = sio;
> + siochan->no = i;
> + siochan->vc.desc_free = sio_tx_free;
> + INIT_WORK(&siochan->terminate_wq, sio_terminate_work);
> + vchan_init(&siochan->vc, dma);
> + }
> +
> + writel(CPU_CONTROL_RUN, sio->base + REG_CPU_CONTROL);
> +
> + err = apple_rtkit_boot(sio->rtk);
> + if (err)
> + return dev_err_probe(&pdev->dev, err, "SIO did not boot\n");
> +
> + err = apple_rtkit_start_ep(sio->rtk, EP_SIO);
> + if (err)
> + return dev_err_probe(&pdev->dev, err, "starting SIO endpoint\n");
> +
> + err = sio_call(sio, FIELD_PREP(SIOMSG_TYPE, MSG_START));
> + if (err < 1) {
> + if (err == 0)
> + err = -ENXIO;
> + return dev_err_probe(&pdev->dev, err, "starting SIO service\n");
> + }
> +
> + err = sio_send_dt_params(sio);
> + if (err < 0)
> + return dev_err_probe(&pdev->dev, err, "failed to send boot-up parameters\n");
> +
> + err = sio_alloc_shmem(sio);
> + if (err < 0)
> + return err;
> +
> + err = dma_async_device_register(&sio->dma);
> + if (err)
> + return dev_err_probe(&pdev->dev, err, "failed to register DMA device\n");
> +
> + err = of_dma_controller_register(pdev->dev.of_node, sio_dma_of_xlate, sio);
> + if (err) {
> + dma_async_device_unregister(&sio->dma);
> + return dev_err_probe(&pdev->dev, err, "failed to register with OF\n");
> + }
> +
> + return 0;
> +}
> +
> +static int sio_remove(struct platform_device *pdev)
> +{
> + struct sio_data *sio = platform_get_drvdata(pdev);
> +
> + of_dma_controller_free(pdev->dev.of_node);
> + dma_async_device_unregister(&sio->dma);
> + return 0;
> +}
> +
> +static const struct of_device_id sio_of_match[] = {
> + { .compatible = "apple,sio", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, sio_of_match);
> +
> +static struct platform_driver apple_sio_driver = {
> + .driver = {
> + .name = "apple-sio",
> + .of_match_table = sio_of_match,
> + },
> + .probe = sio_probe,
> + .remove = sio_remove,
> +};
> +module_platform_driver(apple_sio_driver);
> +
> +MODULE_AUTHOR("Martin Povišer <povik+lin@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Driver for SIO coprocessor on Apple SoCs");
> +MODULE_LICENSE("Dual MIT/GPL");
> --
> 2.38.3
--
~Vinod
