[PATCH 2/2] dmaengine: apple-admac: Add Apple ADMAC driver

Martin Povišer
2022-03-30T16:45:34Z

Add driver for Audio DMA Controller present on Apple SoCs from the
"Apple Silicon" family.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
---
MAINTAINERS | 2 +
drivers/dma/Kconfig | 8 +
drivers/dma/Makefile | 1 +
drivers/dma/apple-admac.c | 799 ++++++++++++++++++++++++++++++++++++++
4 files changed, 810 insertions(+)
create mode 100644 drivers/dma/apple-admac.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d9812b70c322..c6311a921190 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1837,6 +1837,7 @@ T: git https://github.com/AsahiLinux/linux.git
F: Documentation/devicetree/bindings/arm/apple.yaml
F: Documentation/devicetree/bindings/arm/apple/*
F: Documentation/devicetree/bindings/clock/apple,nco.yaml
+F: Documentation/devicetree/bindings/dma/apple,admac.yaml
F: Documentation/devicetree/bindings/i2c/apple,i2c.yaml
F: Documentation/devicetree/bindings/interrupt-controller/apple,*
F: Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
@@ -1846,6 +1847,7 @@ F: Documentation/devicetree/bindings/power/apple*
F: Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
F: arch/arm64/boot/dts/apple/
F: drivers/clk/clk-apple-nco.c
+F: drivers/dma/apple-admac.c
F: drivers/i2c/busses/i2c-pasemi-core.c
F: drivers/i2c/busses/i2c-pasemi-platform.c
F: drivers/irqchip/irq-apple-aic.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index d5de3f77d3aa..dd13bc47eb06 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -85,6 +85,14 @@ config AMCC_PPC440SPE_ADMA
help
Enable support for the AMCC PPC440SPe RAID engines.

+config APPLE_ADMAC
+ tristate "Apple ADMAC support"
+ depends on ARCH_APPLE || COMPILE_TEST
+ select DMA_ENGINE
+ default ARCH_APPLE
+ help
+ Enable support for Audio DMA Controller found on Apple Silicon SoCs.
+
config AT_HDMAC
tristate "Atmel AHB DMA support"
depends on ARCH_AT91
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 616d926cf2a5..28e743c7d86f 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_ALTERA_MSGDMA) += altera-msgdma.o
obj-$(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_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-admac.c b/drivers/dma/apple-admac.c
new file mode 100644
index 000000000000..e7fd9856474e
--- /dev/null
+++ b/drivers/dma/apple-admac.c
@@ -0,0 +1,799 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Audio DMA Controller (ADMAC) on t8103 (M1) and other Apple chips
+ *
+ * Copyright (C) The Asahi Linux Contributors
+ */
+
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+
+#include "dmaengine.h"
+
+#define NCHANNELS_MAX 64
+#define IRQ_NINDICES 4
+
+#define RING_WRITE_SLOT GENMASK(1, 0)
+#define RING_READ_SLOT GENMASK(5, 4)
+#define RING_FULL BIT(9)
+#define RING_EMPTY BIT(8)
+#define RING_ERR BIT(10)
+
+#define STATUS_DESC_DONE BIT(0)
+#define STATUS_ERR BIT(6)
+
+#define FLAG_DESC_NOTIFY BIT(16)
+
+#define REG_TX_START 0x0000
+#define REG_TX_STOP 0x0004
+#define REG_RX_START 0x0008
+#define REG_RX_STOP 0x000c
+
+#define REG_CHAN_CTL(ch) (0x8000 + (ch) * 0x200)
+#define REG_CHAN_CTL_RST_RINGS BIT(0)
+
+#define REG_DESC_RING(ch) (0x8070 + (ch) * 0x200)
+#define REG_REPORT_RING(ch) (0x8074 + (ch) * 0x200)
+
+#define REG_RESIDUE(ch) (0x8064 + (ch) * 0x200)
+
+#define REG_BUS_WIDTH(ch) (0x8040 + (ch) * 0x200)
+
+#define BUS_WIDTH_8BIT 0x00
+#define BUS_WIDTH_16BIT 0x01
+#define BUS_WIDTH_32BIT 0x02
+#define BUS_WIDTH_FRAME_2_WORDS 0x10
+#define BUS_WIDTH_FRAME_4_WORDS 0x20
+
+#define CHAN_BUFSIZE 0x8000
+
+#define REG_CHAN_FIFOCTL(ch) (0x8054 + (ch) * 0x200)
+#define CHAN_FIFOCTL_LIMIT GENMASK(31, 16)
+#define CHAN_FIFOCTL_THRESHOLD GENMASK(15, 0)
+
+#define REG_DESC_WRITE(ch) (0x10000 + ((ch) / 2) * 0x4 + ((ch) & 1) * 0x4000)
+#define REG_REPORT_READ(ch) (0x10100 + ((ch) / 2) * 0x4 + ((ch) & 1) * 0x4000)
+
+#define REG_TX_INTSTATE(idx) (0x0030 + (idx) * 4)
+#define REG_RX_INTSTATE(idx) (0x0040 + (idx) * 4)
+#define REG_CHAN_INTSTATUS(ch, idx) (0x8010 + (ch) * 0x200 + (idx) * 4)
+#define REG_CHAN_INTMASK(ch, idx) (0x8020 + (ch) * 0x200 + (idx) * 4)
+
+struct admac_data;
+struct admac_tx;
+
+struct admac_chan {
+ int no;
+ struct admac_data *host;
+ struct dma_chan chan;
+ struct tasklet_struct tasklet;
+
+ spinlock_t lock;
+ struct admac_tx *current_tx;
+ int nperiod_acks;
+
+ struct list_head submitted;
+ struct list_head issued;
+};
+
+struct admac_data {
+ struct dma_device dma;
+ struct device *dev;
+ __iomem void *base;
+
+ int irq_index;
+ int nchannels;
+ struct admac_chan channels[];
+};
+
+struct admac_tx {
+ struct dma_async_tx_descriptor tx;
+ bool cyclic;
+ dma_addr_t buf_addr;
+ dma_addr_t buf_end;
+ size_t buf_len;
+ size_t period_len;
+
+ size_t submitted_pos;
+ size_t reclaimed_pos;
+
+ struct list_head node;
+};
+
+static void admac_poke(struct admac_data *ad, int reg, u32 val)
+{
+ writel_relaxed(val, ad->base + reg);
+}
+
+static u32 admac_peek(struct admac_data *ad, int reg)
+{
+ return readl_relaxed(ad->base + reg);
+}
+
+static void admac_modify(struct admac_data *ad, int reg, u32 mask, u32 val)
+{
+ void __iomem *addr = ad->base + reg;
+ u32 curr = readl_relaxed(addr);
+
+ writel_relaxed((curr & ~mask) | (val & mask), addr);
+}
+
+static struct admac_chan *to_admac_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct admac_chan, chan);
+}
+
+static struct admac_tx *to_admac_tx(struct dma_async_tx_descriptor *tx)
+{
+ return container_of(tx, struct admac_tx, tx);
+}
+
+static enum dma_transfer_direction admac_chan_direction(int channo)
+{
+ return (channo & 1) ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
+}
+
+static dma_cookie_t admac_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct admac_tx *adtx = to_admac_tx(tx);
+ struct admac_chan *adchan = to_admac_chan(tx->chan);
+ unsigned long flags;
+ dma_cookie_t cookie;
+
+ spin_lock_irqsave(&adchan->lock, flags);
+ cookie = dma_cookie_assign(tx);
+ list_add_tail(&adtx->node, &adchan->submitted);
+ spin_unlock_irqrestore(&adchan->lock, flags);
+
+ return cookie;
+}
+
+static int admac_desc_free(struct dma_async_tx_descriptor *tx)
+{
+ struct admac_tx *adtx = to_admac_tx(tx);
+
+ devm_kfree(to_admac_chan(tx->chan)->host->dev, adtx);
+ return 0;
+}
+
+static struct dma_async_tx_descriptor *admac_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 admac_chan *adchan = container_of(chan, struct admac_chan, chan);
+ struct admac_tx *adtx;
+
+ if (direction != admac_chan_direction(adchan->no))
+ return NULL;
+
+ adtx = devm_kzalloc(adchan->host->dev, sizeof(*adtx), GFP_NOWAIT);
+ if (!adtx)
+ return NULL;
+
+ adtx->cyclic = true;
+
+ adtx->buf_addr = buf_addr;
+ adtx->buf_len = buf_len;
+ adtx->buf_end = buf_addr + buf_len;
+ adtx->period_len = period_len;
+
+ adtx->submitted_pos = 0;
+ adtx->reclaimed_pos = 0;
+
+ dma_async_tx_descriptor_init(&adtx->tx, chan);
+ adtx->tx.tx_submit = admac_tx_submit;
+ adtx->tx.desc_free = admac_desc_free;
+
+ return &adtx->tx;
+}
+
+/*
+ * Write one hardware descriptor for a dmaengine cyclic transaction.
+ */
+static void admac_cyclic_write_one_desc(struct admac_data *ad, int channo,
+ struct admac_tx *tx)
+{
+ dma_addr_t addr;
+
+ if (WARN_ON(!tx->cyclic))
+ return;
+
+ addr = tx->buf_addr + (tx->submitted_pos % tx->buf_len);
+ WARN_ON(addr + tx->period_len > tx->buf_end);
+
+ dev_dbg(ad->dev, "ch%d descriptor: addr=0x%pad len=0x%zx flags=0x%x\n",
+ channo, addr, tx->period_len, FLAG_DESC_NOTIFY);
+
+ admac_poke(ad, REG_DESC_WRITE(channo), addr);
+ admac_poke(ad, REG_DESC_WRITE(channo), addr >> 32);
+ admac_poke(ad, REG_DESC_WRITE(channo), tx->period_len);
+ admac_poke(ad, REG_DESC_WRITE(channo), FLAG_DESC_NOTIFY);
+
+ tx->submitted_pos += tx->period_len;
+ tx->submitted_pos %= 2 * tx->buf_len;
+}
+
+/*
+ * Write all the hardware descriptors for a cyclic transaction
+ * there is space for.
+ */
+static void admac_cyclic_write_desc(struct admac_data *ad, int channo,
+ struct admac_tx *tx)
+{
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ if (admac_peek(ad, REG_DESC_RING(channo)) & RING_FULL)
+ break;
+ admac_cyclic_write_one_desc(ad, channo, tx);
+ }
+}
+
+static int admac_ring_noccupied_slots(int ringval)
+{
+ int wrslot = FIELD_GET(RING_WRITE_SLOT, ringval);
+ int rdslot = FIELD_GET(RING_READ_SLOT, ringval);
+
+ if (wrslot != rdslot) {
+ return (wrslot + 4 - rdslot) % 4;
+ } else {
+ WARN_ON((ringval & (RING_FULL | RING_EMPTY)) == 0);
+
+ if (ringval & RING_FULL)
+ return 4;
+ else
+ return 0;
+ }
+}
+
+/*
+ * Read from hardware the residue of a cyclic dmaengine transaction.
+ */
+static u32 admac_cyclic_read_residue(struct admac_data *ad, int channo,
+ struct admac_tx *adtx)
+{
+ u32 ring1, ring2;
+ u32 residue1, residue2;
+ int nreports;
+ size_t pos;
+
+ ring1 = admac_peek(ad, REG_REPORT_RING(channo));
+ residue1 = admac_peek(ad, REG_RESIDUE(channo));
+ ring2 = admac_peek(ad, REG_REPORT_RING(channo));
+ residue2 = admac_peek(ad, REG_RESIDUE(channo));
+
+ if (residue2 > residue1) {
+ /*
+ * Controller must have loaded next descriptor between
+ * the two residue reads
+ */
+ nreports = admac_ring_noccupied_slots(ring1) + 1;
+ } else {
+ /* No descriptor load between the two reads, ring2 is safe to use */
+ nreports = admac_ring_noccupied_slots(ring2);
+ }
+
+ pos = adtx->reclaimed_pos + adtx->period_len * (nreports + 1) - residue2;
+
+ return adtx->buf_len - pos % adtx->buf_len;
+}
+
+static enum dma_status admac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+ struct admac_data *ad = adchan->host;
+ struct admac_tx *adtx;
+
+ enum dma_status ret;
+ size_t residue;
+ unsigned long flags;
+
+ ret = dma_cookie_status(chan, cookie, txstate);
+ if (ret == DMA_COMPLETE || !txstate)
+ return ret;
+
+ spin_lock_irqsave(&adchan->lock, flags);
+ adtx = adchan->current_tx;
+
+ if (adtx && adtx->tx.cookie == cookie) {
+ ret = DMA_IN_PROGRESS;
+ residue = admac_cyclic_read_residue(ad, adchan->no, adtx);
+ } else {
+ ret = DMA_IN_PROGRESS;
+ residue = 0;
+ list_for_each_entry(adtx, &adchan->issued, node) {
+ if (adtx->tx.cookie == cookie) {
+ residue = adtx->buf_len;
+ break;
+ }
+ }
+ }
+ spin_unlock_irqrestore(&adchan->lock, flags);
+
+ dma_set_residue(txstate, residue);
+ return ret;
+}
+
+static void admac_start_chan(struct admac_chan *adchan)
+{
+ u32 startbit = 1 << (adchan->no / 2);
+
+ switch (admac_chan_direction(adchan->no)) {
+ case DMA_MEM_TO_DEV:
+ admac_poke(adchan->host, REG_TX_START, startbit);
+ break;
+ case DMA_DEV_TO_MEM:
+ admac_poke(adchan->host, REG_RX_START, startbit);
+ break;
+ default:
+ break;
+ }
+ dev_dbg(adchan->host->dev, "ch%d start\n", adchan->no);
+}
+
+static void admac_stop_chan(struct admac_chan *adchan)
+{
+ u32 stopbit = 1 << (adchan->no / 2);
+
+ switch (admac_chan_direction(adchan->no)) {
+ case DMA_MEM_TO_DEV:
+ admac_poke(adchan->host, REG_TX_STOP, stopbit);
+ break;
+ case DMA_DEV_TO_MEM:
+ admac_poke(adchan->host, REG_RX_STOP, stopbit);
+ break;
+ default:
+ break;
+ }
+ dev_dbg(adchan->host->dev, "ch%d stop\n", adchan->no);
+}
+
+static void admac_start_current_tx(struct admac_chan *adchan)
+{
+ struct admac_data *ad = adchan->host;
+ int ch = adchan->no;
+
+ admac_poke(ad, REG_CHAN_INTSTATUS(ch, ad->irq_index),
+ STATUS_DESC_DONE | STATUS_ERR);
+ admac_poke(ad, REG_CHAN_CTL(ch), REG_CHAN_CTL_RST_RINGS);
+ admac_poke(ad, REG_CHAN_CTL(ch), 0);
+
+ admac_cyclic_write_one_desc(ad, ch, adchan->current_tx);
+ admac_start_chan(adchan);
+ admac_cyclic_write_desc(ad, ch, adchan->current_tx);
+}
+
+static void admac_issue_pending(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+ struct admac_tx *tx;
+ unsigned long flags;
+
+ spin_lock_irqsave(&adchan->lock, flags);
+ list_splice_tail_init(&adchan->submitted, &adchan->issued);
+ if (!list_empty(&adchan->issued) && !adchan->current_tx) {
+ tx = list_first_entry(&adchan->issued, struct admac_tx, node);
+ list_del(&tx->node);
+
+ adchan->current_tx = tx;
+ adchan->nperiod_acks = 0;
+ admac_start_current_tx(adchan);
+ }
+ spin_unlock_irqrestore(&adchan->lock, flags);
+}
+
+static int admac_pause(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+
+ admac_stop_chan(adchan);
+
+ return 0;
+}
+
+static int admac_resume(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+
+ admac_start_chan(adchan);
+
+ return 0;
+}
+
+static int admac_terminate_all(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+ struct admac_tx *adtx, *_adtx;
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&adchan->lock, flags);
+ admac_stop_chan(adchan);
+ adchan->current_tx = NULL;
+ list_splice_tail_init(&adchan->submitted, &head);
+ list_splice_tail_init(&adchan->issued, &head);
+ spin_unlock_irqrestore(&adchan->lock, flags);
+
+ list_for_each_entry_safe(adtx, _adtx, &head, node) {
+ list_del(&adtx->node);
+ admac_desc_free(&adtx->tx);
+ }
+
+ return 0;
+}
+
+static int admac_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+ struct admac_data *ad = adchan->host;
+
+ dma_cookie_init(&adchan->chan);
+ admac_poke(ad, REG_CHAN_INTSTATUS(adchan->no, ad->irq_index),
+ STATUS_DESC_DONE | STATUS_ERR);
+ admac_poke(ad, REG_CHAN_INTMASK(adchan->no, ad->irq_index),
+ STATUS_DESC_DONE | STATUS_ERR);
+ return 0;
+}
+
+static void admac_free_chan_resources(struct dma_chan *chan)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+
+ admac_terminate_all(chan);
+ tasklet_kill(&adchan->tasklet);
+}
+
+static struct dma_chan *admac_dma_of_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct admac_data *ad = (struct admac_data *) ofdma->of_dma_data;
+ unsigned int index;
+
+ if (dma_spec->args_count != 1)
+ return NULL;
+
+ index = dma_spec->args[0];
+
+ if (index >= ad->nchannels) {
+ dev_err(ad->dev, "channel index %u out of bounds\n", index);
+ return NULL;
+ }
+
+ return &ad->channels[index].chan;
+}
+
+static int admac_drain_reports(struct admac_data *ad, int channo)
+{
+ int count;
+
+ for (count = 0; count < 4; count++) {
+ u32 countval_hi, countval_lo, unk1, flags;
+
+ if (admac_peek(ad, REG_REPORT_RING(channo)) & RING_EMPTY)
+ break;
+
+ countval_lo = admac_peek(ad, REG_REPORT_READ(channo));
+ countval_hi = admac_peek(ad, REG_REPORT_READ(channo));
+ unk1 = admac_peek(ad, REG_REPORT_READ(channo));
+ flags = admac_peek(ad, REG_REPORT_READ(channo));
+
+ dev_dbg(ad->dev, "ch%d report: countval=0x%llx unk1=0x%x flags=0x%x\n",
+ channo, ((u64) countval_hi) << 32 | countval_lo, unk1, flags);
+ }
+
+ return count;
+}
+
+static void admac_handle_status_err(struct admac_data *ad, int channo)
+{
+ bool handled = false;
+
+ if (admac_peek(ad, REG_DESC_RING(channo) & RING_ERR)) {
+ admac_poke(ad, REG_DESC_RING(channo), RING_ERR);
+ dev_err(ad->dev, "ch%d descriptor ring error\n", channo);
+ handled = true;
+ }
+
+ if (admac_peek(ad, REG_REPORT_RING(channo)) & RING_ERR) {
+ admac_poke(ad, REG_REPORT_RING(channo), RING_ERR);
+ dev_err(ad->dev, "ch%d report ring error\n", channo);
+ handled = true;
+ }
+
+ if (unlikely(!handled)) {
+ dev_err(ad->dev, "ch%d unknown error, masking errors as cause of IRQs\n", channo);
+ admac_modify(ad, REG_CHAN_INTMASK(channo, ad->irq_index),
+ STATUS_ERR, 0);
+ }
+}
+
+static void admac_handle_status_desc_done(struct admac_data *ad, int channo)
+{
+ struct admac_chan *adchan = &ad->channels[channo];
+ unsigned long flags;
+ int nreports;
+
+ admac_poke(ad, REG_CHAN_INTSTATUS(channo, ad->irq_index),
+ STATUS_DESC_DONE);
+
+ spin_lock_irqsave(&adchan->lock, flags);
+ nreports = admac_drain_reports(ad, channo);
+
+ if (adchan->current_tx) {
+ struct admac_tx *tx = adchan->current_tx;
+
+ adchan->nperiod_acks += nreports;
+ tx->reclaimed_pos += nreports * tx->period_len;
+ tx->reclaimed_pos %= 2 * tx->buf_len;
+
+ admac_cyclic_write_desc(ad, channo, tx);
+ tasklet_schedule(&adchan->tasklet);
+ }
+ spin_unlock_irqrestore(&adchan->lock, flags);
+}
+
+static void admac_handle_chan_int(struct admac_data *ad, int no)
+{
+ u32 cause = admac_peek(ad, REG_CHAN_INTSTATUS(no, ad->irq_index));
+
+ if (cause & STATUS_ERR)
+ admac_handle_status_err(ad, no);
+
+ if (cause & STATUS_DESC_DONE)
+ admac_handle_status_desc_done(ad, no);
+}
+
+static irqreturn_t admac_interrupt(int irq, void *devid)
+{
+ struct admac_data *ad = devid;
+ u32 rx_intstate, tx_intstate;
+ int i;
+
+ rx_intstate = admac_peek(ad, REG_RX_INTSTATE(ad->irq_index));
+ tx_intstate = admac_peek(ad, REG_TX_INTSTATE(ad->irq_index));
+
+ if (!tx_intstate && !rx_intstate)
+ return IRQ_NONE;
+
+ for (i = 0; i < ad->nchannels; i += 2) {
+ if (tx_intstate & 1)
+ admac_handle_chan_int(ad, i);
+ tx_intstate >>= 1;
+ }
+
+ for (i = 1; i < ad->nchannels; i += 2) {
+ if (rx_intstate & 1)
+ admac_handle_chan_int(ad, i);
+ rx_intstate >>= 1;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void admac_chan_tasklet(struct tasklet_struct *t)
+{
+ struct admac_chan *adchan = from_tasklet(adchan, t, tasklet);
+ struct admac_tx *adtx;
+ struct dmaengine_desc_callback cb;
+ struct dmaengine_result tx_result;
+ int nacks;
+
+ spin_lock_irq(&adchan->lock);
+ adtx = adchan->current_tx;
+ nacks = adchan->nperiod_acks;
+ adchan->nperiod_acks = 0;
+ spin_unlock_irq(&adchan->lock);
+
+ if (!adtx || !nacks)
+ return;
+
+ tx_result.result = DMA_TRANS_NOERROR;
+ tx_result.residue = 0;
+
+ dmaengine_desc_get_callback(&adtx->tx, &cb);
+ while (nacks--)
+ dmaengine_desc_callback_invoke(&cb, &tx_result);
+}
+
+static int admac_device_config(struct dma_chan *chan,
+ struct dma_slave_config *config)
+{
+ struct admac_chan *adchan = to_admac_chan(chan);
+ struct admac_data *ad = adchan->host;
+ bool is_tx = admac_chan_direction(adchan->no) == DMA_MEM_TO_DEV;
+ int wordsize = 0;
+ u32 bus_width = 0;
+
+ switch (is_tx ? config->dst_addr_width : config->src_addr_width) {
+ case DMA_SLAVE_BUSWIDTH_1_BYTE:
+ wordsize = 1;
+ bus_width |= BUS_WIDTH_8BIT;
+ break;
+ case DMA_SLAVE_BUSWIDTH_2_BYTES:
+ wordsize = 2;
+ bus_width |= BUS_WIDTH_16BIT;
+ break;
+ case DMA_SLAVE_BUSWIDTH_4_BYTES:
+ wordsize = 4;
+ bus_width |= BUS_WIDTH_32BIT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /*
+ * We take port_window_size to be the number of words in a frame.
+ *
+ * The controller has some means of out-of-band signalling, to the peripheral,
+ * of words position in a frame. That's where the importance of this control
+ * comes from.
+ */
+ switch (is_tx ? config->dst_port_window_size : config->src_port_window_size) {
+ case 0 ... 1:
+ break;
+ case 2:
+ bus_width |= BUS_WIDTH_FRAME_2_WORDS;
+ break;
+ case 4:
+ bus_width |= BUS_WIDTH_FRAME_4_WORDS;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ admac_poke(ad, REG_BUS_WIDTH(adchan->no), bus_width);
+
+ /*
+ * By FIFOCTL_LIMIT we seem to set the maximal number of bytes allowed to be
+ * held in controller's per-channel FIFO. Transfers seem to be triggered
+ * around the time FIFO occupancy touches FIFOCTL_THRESHOLD.
+ *
+ * The numbers we set are more or less arbitrary.
+ */
+ admac_poke(ad, REG_CHAN_FIFOCTL(adchan->no),
+ FIELD_PREP(CHAN_FIFOCTL_LIMIT, 0x30 * wordsize)
+ | FIELD_PREP(CHAN_FIFOCTL_THRESHOLD, 0x18 * wordsize));
+
+ return 0;
+}
+
+static int admac_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct admac_data *ad;
+ struct dma_device *dma;
+ int nchannels;
+ int err, irq, i;
+
+ err = of_property_read_u32(np, "dma-channels", &nchannels);
+ if (err || nchannels > NCHANNELS_MAX) {
+ dev_err(&pdev->dev, "missing or invalid dma-channels property\n");
+ return -EINVAL;
+ }
+
+ ad = devm_kzalloc(&pdev->dev, struct_size(ad, channels, nchannels), GFP_KERNEL);
+ if (!ad)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, ad);
+ ad->dev = &pdev->dev;
+ ad->nchannels = nchannels;
+
+ err = of_property_read_u32(np, "apple,internal-irq-destination",
+ &ad->irq_index);
+ if (err || ad->irq_index >= IRQ_NINDICES) {
+ dev_err(&pdev->dev, "missing or invalid apple,internal-irq-destination property\n");
+ return -EINVAL;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "unable to obtain interrupt resource\n");
+ return irq;
+ }
+
+ err = devm_request_irq(&pdev->dev, irq, admac_interrupt,
+ 0, dev_name(&pdev->dev), ad);
+ if (err) {
+ dev_err(&pdev->dev, "unable to register interrupt: %d\n", err);
+ return err;
+ }
+
+ ad->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(ad->base)) {
+ dev_err(&pdev->dev, "unable to obtain MMIO resource\n");
+ return PTR_ERR(ad->base);
+ }
+
+ dma = &ad->dma;
+
+ dma_cap_set(DMA_PRIVATE, dma->cap_mask);
+ dma_cap_set(DMA_CYCLIC, dma->cap_mask);
+
+ dma->dev = &pdev->dev;
+ dma->device_alloc_chan_resources = admac_alloc_chan_resources;
+ dma->device_free_chan_resources = admac_free_chan_resources;
+ dma->device_tx_status = admac_tx_status;
+ dma->device_issue_pending = admac_issue_pending;
+ dma->device_terminate_all = admac_terminate_all;
+ dma->device_prep_dma_cyclic = admac_prep_dma_cyclic;
+ dma->device_config = admac_device_config;
+ dma->device_pause = admac_pause;
+ dma->device_resume = admac_resume;
+
+ dma->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
+ dma->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+ 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 admac_chan *adchan = &ad->channels[i];
+
+ adchan->host = ad;
+ adchan->no = i;
+ adchan->chan.device = &ad->dma;
+ spin_lock_init(&adchan->lock);
+ INIT_LIST_HEAD(&adchan->submitted);
+ INIT_LIST_HEAD(&adchan->issued);
+ list_add_tail(&adchan->chan.device_node, &dma->channels);
+ tasklet_setup(&adchan->tasklet, admac_chan_tasklet);
+ }
+
+ err = dma_async_device_register(&ad->dma);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register DMA device: %d\n", err);
+ return err;
+ }
+
+ err = of_dma_controller_register(pdev->dev.of_node, admac_dma_of_xlate, ad);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register with OF: %d\n", err);
+ dma_async_device_unregister(&ad->dma);
+ return err;
+ }
+
+ dev_dbg(&pdev->dev, "all good, ready to go!\n");
+
+ return 0;
+}
+
+static int admac_remove(struct platform_device *pdev)
+{
+ struct admac_data *ad = platform_get_drvdata(pdev);
+
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(&ad->dma);
+
+ return 0;
+}
+
+static const struct of_device_id admac_of_match[] = {
+ { .compatible = "apple,admac", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, admac_of_match);
+
+static struct platform_driver apple_admac_driver = {
+ .driver = {
+ .name = "apple-admac",
+ .of_match_table = admac_of_match,
+ },
+ .probe = admac_probe,
+ .remove = admac_remove,
+};
+module_platform_driver(apple_admac_driver);
+
+MODULE_AUTHOR("Martin Povišer <povik+lin@cutebit.org>");
+MODULE_DESCRIPTION("Driver for Audio DMA Controller (ADMAC) on Apple SoCs");
+MODULE_LICENSE("GPL");
--
2.33.0