usb: musb dma: add cppi41 dma driver

This driver is currently used by musb' cppi41 couter part. I may merge
both dma engine user of musb at some point but not just yet.

The driver seems to work in RX/TX mode in host mode, tested on mass
storage. I increaed the size of the TX / RX transfers and waited for the
core code to cancel a transfers and it seems to recover.

v2..3:
- use mall transfers on RX side and check data toggle.
- use rndis mode on tx side so we haveon interrupt for 4096 transfers.
- remove custom "transferred" hack and use dmaengine_tx_status() to
  compute the total amount of data that has been transferred.
- cancel transfers and reclaim descriptors

v1..v2:
- RX path added
- dma mode 0 & 1 is working
- device tree nodes re-created.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <djbw@fb.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

4 files changed, 558 insertions, 1 deletions

diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index b7257ae..04658d7 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -129,6 +129,10 @@ config USB_TI_CPPI_DMA
 	help
 	  Enable DMA transfers when TI CPPI DMA is available.
 
+config USB_TI_CPPI41_DMA
+	bool 'TI CPPI 4.1 (AM335x)'
+	depends on ARCH_OMAP
+
 config USB_TUSB_OMAP_DMA
 	bool 'TUSB 6010'
 	depends on USB_MUSB_TUSB6010
diff --git a/drivers/usb/musb/Makefile b/drivers/usb/musb/Makefile
index 52f552c..c5ea5c6 100644
--- a/drivers/usb/musb/Makefile
+++ b/drivers/usb/musb/Makefile
@@ -32,3 +32,4 @@ musb_hdrc-$(CONFIG_USB_INVENTRA_DMA)		+= musbhsdma.o
 musb_hdrc-$(CONFIG_USB_TI_CPPI_DMA)		+= cppi_dma.o
 musb_hdrc-$(CONFIG_USB_TUSB_OMAP_DMA)		+= tusb6010_omap.o
 musb_hdrc-$(CONFIG_USB_UX500_DMA)		+= ux500_dma.o
+musb_hdrc-$(CONFIG_USB_TI_CPPI41_DMA)		+= musb_cppi41.o
diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
new file mode 100644
index 0000000..a74259ea
--- /dev/null
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -0,0 +1,552 @@
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/sizes.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+#include "musb_core.h"
+
+#define RNDIS_REG(x) (0x80 + ((x - 1) * 4))
+
+#define EP_MODE_AUTOREG_NONE		0
+#define EP_MODE_AUTOREG_ALL_NEOP	1
+#define EP_MODE_AUTOREG_ALWAYS		3
+
+#define EP_MODE_DMA_TRANSPARENT		0
+#define EP_MODE_DMA_RNDIS		1
+#define EP_MODE_DMA_GEN_RNDIS		3
+
+#define USB_CTRL_TX_MODE	0x70
+#define USB_CTRL_RX_MODE	0x74
+#define USB_CTRL_AUTOREQ	0xd0
+#define USB_TDOWN		0xd8
+
+struct cppi41_dma_channel {
+	struct dma_channel channel;
+	struct cppi41_dma_controller *controller;
+	struct musb_hw_ep *hw_ep;
+	struct dma_chan *dc;
+	dma_cookie_t cookie;
+	u8 port_num;
+	u8 is_tx;
+	u8 is_allocated;
+	u8 usb_toggle;
+
+	dma_addr_t buf_addr;
+	u32 total_len;
+	u32 prog_len;
+	u32 transferred;
+	u32 packet_sz;
+};
+
+#define MUSB_DMA_NUM_CHANNELS 15
+
+struct cppi41_dma_controller {
+	struct dma_controller controller;
+	struct cppi41_dma_channel rx_channel[MUSB_DMA_NUM_CHANNELS];
+	struct cppi41_dma_channel tx_channel[MUSB_DMA_NUM_CHANNELS];
+	struct musb *musb;
+	u32 rx_mode;
+	u32 tx_mode;
+	u32 auto_req;
+};
+
+static void save_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
+{
+	u16 csr;
+	u8 toggle;
+
+	if (cppi41_channel->is_tx)
+		return;
+	if (!is_host_active(cppi41_channel->controller->musb))
+		return;
+
+	csr = musb_readw(cppi41_channel->hw_ep->regs, MUSB_RXCSR);
+	toggle = csr & MUSB_RXCSR_H_DATATOGGLE ? 1 : 0;
+
+	cppi41_channel->usb_toggle = toggle;
+}
+
+static void update_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
+{
+	u16 csr;
+	u8 toggle;
+
+	if (cppi41_channel->is_tx)
+		return;
+	if (!is_host_active(cppi41_channel->controller->musb))
+		return;
+
+	csr = musb_readw(cppi41_channel->hw_ep->regs, MUSB_RXCSR);
+	toggle = csr & MUSB_RXCSR_H_DATATOGGLE ? 1 : 0;
+
+	/*
+	 * AM335x Advisory 1.0.13: Due to internal synchronisation error the
+	 * data toggle may reset from DATA1 to DATA0 during receiving data from
+	 * more than one endpoint.
+	 */
+	if (!toggle && toggle == cppi41_channel->usb_toggle) {
+		csr |= MUSB_RXCSR_H_DATATOGGLE | MUSB_RXCSR_H_WR_DATATOGGLE;
+		musb_writew(cppi41_channel->hw_ep->regs, MUSB_RXCSR, csr);
+		dev_dbg(cppi41_channel->controller->musb->controller,
+				"Restoring DATA1 toggle.\n");
+	}
+
+	cppi41_channel->usb_toggle = toggle;
+}
+
+static void cppi41_dma_callback(void *private_data)
+{
+	struct dma_channel *channel = private_data;
+	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
+	struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
+	struct musb *musb = hw_ep->musb;
+	unsigned long flags;
+	struct dma_tx_state txstate;
+	u32 transferred;
+
+	spin_lock_irqsave(&musb->lock, flags);
+
+	dmaengine_tx_status(cppi41_channel->dc, cppi41_channel->cookie,
+			&txstate);
+	transferred = cppi41_channel->prog_len - txstate.residue;
+	cppi41_channel->transferred += transferred;
+
+	dev_dbg(musb->controller, "DMA transfer done on hw_ep=%d bytes=%d/%d\n",
+		hw_ep->epnum, cppi41_channel->transferred,
+		cppi41_channel->total_len);
+
+	update_rx_toggle(cppi41_channel);
+
+	if (cppi41_channel->transferred == cppi41_channel->total_len ||
+			transferred < cppi41_channel->packet_sz) {
+
+		/* done, complete */
+		cppi41_channel->channel.actual_len =
+			cppi41_channel->transferred;
+		cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
+		musb_dma_completion(musb, hw_ep->epnum, cppi41_channel->is_tx);
+	} else {
+		/* next iteration, reload */
+		struct dma_chan *dc = cppi41_channel->dc;
+		struct dma_async_tx_descriptor *dma_desc;
+		enum dma_transfer_direction direction;
+		u16 csr;
+		u32 remain_bytes;
+		void __iomem *epio = cppi41_channel->hw_ep->regs;
+
+		cppi41_channel->buf_addr += cppi41_channel->packet_sz;
+
+		remain_bytes = cppi41_channel->total_len;
+		remain_bytes -= cppi41_channel->transferred;
+		remain_bytes = min(remain_bytes, cppi41_channel->packet_sz);
+		cppi41_channel->prog_len = remain_bytes;
+
+		direction = cppi41_channel->is_tx ? DMA_MEM_TO_DEV
+			: DMA_DEV_TO_MEM;
+		dma_desc = dmaengine_prep_slave_single(dc,
+				cppi41_channel->buf_addr,
+				remain_bytes,
+				direction,
+				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (WARN_ON(!dma_desc))
+			return;
+
+		dma_desc->callback = cppi41_dma_callback;
+		dma_desc->callback_param = channel;
+		cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
+		dma_async_issue_pending(dc);
+
+		if (!cppi41_channel->is_tx) {
+			csr = musb_readw(epio, MUSB_RXCSR);
+			csr |= MUSB_RXCSR_H_REQPKT;
+			musb_writew(epio, MUSB_RXCSR, csr);
+		}
+	}
+	spin_unlock_irqrestore(&musb->lock, flags);
+}
+
+static u32 update_ep_mode(unsigned ep, unsigned mode, u32 old)
+{
+	unsigned shift;
+
+	shift = (ep - 1) * 2;
+	old &= ~(3 << shift);
+	old |= mode << shift;
+	return old;
+}
+
+static void cppi41_set_dma_mode(struct cppi41_dma_channel *cppi41_channel,
+		unsigned mode)
+{
+	struct cppi41_dma_controller *controller = cppi41_channel->controller;
+	u32 port;
+	u32 new_mode;
+	u32 old_mode;
+
+	if (cppi41_channel->is_tx)
+		old_mode = controller->tx_mode;
+	else
+		old_mode = controller->rx_mode;
+	port = cppi41_channel->port_num;
+	new_mode = update_ep_mode(port, mode, old_mode);
+
+	if (new_mode == old_mode)
+		return;
+	if (cppi41_channel->is_tx) {
+		controller->tx_mode = new_mode;
+		musb_writel(controller->musb->ctrl_base, USB_CTRL_TX_MODE,
+				new_mode);
+	} else {
+		controller->rx_mode = new_mode;
+		musb_writel(controller->musb->ctrl_base, USB_CTRL_RX_MODE,
+				new_mode);
+	}
+}
+
+static void cppi41_set_autoreq_mode(struct cppi41_dma_channel *cppi41_channel,
+		unsigned mode)
+{
+	struct cppi41_dma_controller *controller = cppi41_channel->controller;
+	u32 port;
+	u32 new_mode;
+	u32 old_mode;
+
+	old_mode = controller->auto_req;
+	port = cppi41_channel->port_num;
+	new_mode = update_ep_mode(port, mode, old_mode);
+
+	if (new_mode == old_mode)
+		return;
+	controller->auto_req = new_mode;
+	musb_writel(controller->musb->ctrl_base, USB_CTRL_AUTOREQ, new_mode);
+}
+
+static bool cppi41_configure_channel(struct dma_channel *channel,
+				u16 packet_sz, u8 mode,
+				dma_addr_t dma_addr, u32 len)
+{
+	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
+	struct dma_chan *dc = cppi41_channel->dc;
+	struct dma_async_tx_descriptor *dma_desc;
+	enum dma_transfer_direction direction;
+	struct musb *musb = cppi41_channel->controller->musb;
+	unsigned use_gen_rndis = 0;
+
+	dev_dbg(musb->controller,
+		"configure ep%d/%x packet_sz=%d, mode=%d, dma_addr=0x%llx, len=%d is_tx=%d\n",
+		cppi41_channel->port_num, RNDIS_REG(cppi41_channel->port_num),
+		packet_sz, mode, (unsigned long long) dma_addr,
+		len, cppi41_channel->is_tx);
+
+	cppi41_channel->buf_addr = dma_addr;
+	cppi41_channel->total_len = len;
+	cppi41_channel->transferred = 0;
+	cppi41_channel->packet_sz = packet_sz;
+
+	/*
+	 * Due to AM335x' Advisory 1.0.13 we are not allowed to transfer more
+	 * than max packet size at a time.
+	 */
+	if (cppi41_channel->is_tx)
+		use_gen_rndis = 1;
+
+	if (use_gen_rndis) {
+		/* RNDIS mode */
+		if (len > packet_sz) {
+			musb_writel(musb->ctrl_base,
+				RNDIS_REG(cppi41_channel->port_num), len);
+			/* gen rndis */
+			cppi41_set_dma_mode(cppi41_channel,
+					EP_MODE_DMA_GEN_RNDIS);
+
+			/* auto req */
+			cppi41_set_autoreq_mode(cppi41_channel,
+					EP_MODE_AUTOREG_ALL_NEOP);
+		} else {
+			musb_writel(musb->ctrl_base,
+					RNDIS_REG(cppi41_channel->port_num), 0);
+			cppi41_set_dma_mode(cppi41_channel,
+					EP_MODE_DMA_TRANSPARENT);
+			cppi41_set_autoreq_mode(cppi41_channel,
+					EP_MODE_AUTOREG_NONE);
+		}
+	} else {
+		/* fallback mode */
+		cppi41_set_dma_mode(cppi41_channel, EP_MODE_DMA_TRANSPARENT);
+		cppi41_set_autoreq_mode(cppi41_channel, EP_MODE_AUTOREG_NONE);
+		len = min_t(u32, packet_sz, len);
+	}
+	cppi41_channel->prog_len = len;
+	direction = cppi41_channel->is_tx ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
+	dma_desc = dmaengine_prep_slave_single(dc, dma_addr, len, direction,
+			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!dma_desc)
+		return false;
+
+	dma_desc->callback = cppi41_dma_callback;
+	dma_desc->callback_param = channel;
+	cppi41_channel->cookie = dma_desc->tx_submit(dma_desc);
+
+	save_rx_toggle(cppi41_channel);
+	dma_async_issue_pending(dc);
+	return true;
+}
+
+static struct dma_channel *cppi41_dma_channel_allocate(struct dma_controller *c,
+				struct musb_hw_ep *hw_ep, u8 is_tx)
+{
+	struct cppi41_dma_controller *controller = container_of(c,
+			struct cppi41_dma_controller, controller);
+	struct cppi41_dma_channel *cppi41_channel = NULL;
+	u8 ch_num = hw_ep->epnum - 1;
+
+	if (ch_num >= MUSB_DMA_NUM_CHANNELS)
+		return NULL;
+
+	if (is_tx)
+		cppi41_channel = &controller->tx_channel[ch_num];
+	else
+		cppi41_channel = &controller->rx_channel[ch_num];
+
+	if (!cppi41_channel->dc)
+		return NULL;
+
+	if (cppi41_channel->is_allocated)
+		return NULL;
+
+	cppi41_channel->hw_ep = hw_ep;
+	cppi41_channel->is_allocated = 1;
+
+	return &cppi41_channel->channel;
+}
+
+static void cppi41_dma_channel_release(struct dma_channel *channel)
+{
+	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
+
+	if (cppi41_channel->is_allocated) {
+		cppi41_channel->is_allocated = 0;
+		channel->status = MUSB_DMA_STATUS_FREE;
+		channel->actual_len = 0;
+	}
+}
+
+static int cppi41_dma_channel_program(struct dma_channel *channel,
+				u16 packet_sz, u8 mode,
+				dma_addr_t dma_addr, u32 len)
+{
+	int ret;
+
+	BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
+		channel->status == MUSB_DMA_STATUS_BUSY);
+
+	channel->status = MUSB_DMA_STATUS_BUSY;
+	channel->actual_len = 0;
+	ret = cppi41_configure_channel(channel, packet_sz, mode, dma_addr, len);
+	if (!ret)
+		channel->status = MUSB_DMA_STATUS_FREE;
+
+	return ret;
+}
+
+static int cppi41_is_compatible(struct dma_channel *channel, u16 maxpacket,
+		void *buf, u32 length)
+{
+	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
+	struct cppi41_dma_controller *controller = cppi41_channel->controller;
+	struct musb *musb = controller->musb;
+
+	if (is_host_active(musb)) {
+		WARN_ON(1);
+		return 1;
+	}
+	return 0;
+}
+
+static int cppi41_dma_channel_abort(struct dma_channel *channel)
+{
+	struct cppi41_dma_channel *cppi41_channel = channel->private_data;
+	struct cppi41_dma_controller *controller = cppi41_channel->controller;
+	struct musb *musb = controller->musb;
+	void __iomem *epio = cppi41_channel->hw_ep->regs;
+	int tdbit;
+	int ret;
+	unsigned is_tx;
+	u16 csr;
+
+	is_tx = cppi41_channel->is_tx;
+	dev_dbg(musb->controller, "abort channel=%d, is_tx=%d\n",
+			cppi41_channel->port_num, is_tx);
+
+	if (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)
+		return 0;
+
+	if (is_tx) {
+		csr = musb_readw(epio, MUSB_TXCSR);
+		csr &= ~MUSB_TXCSR_DMAENAB;
+		musb_writew(epio, MUSB_TXCSR, csr);
+	} else {
+		csr = musb_readw(epio, MUSB_RXCSR);
+		csr &= ~(MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_DMAENAB);
+		musb_writew(epio, MUSB_RXCSR, csr);
+
+		csr = musb_readw(epio, MUSB_RXCSR);
+		if (csr & MUSB_RXCSR_RXPKTRDY) {
+			csr |= MUSB_RXCSR_FLUSHFIFO;
+			musb_writew(epio, MUSB_RXCSR, csr);
+			musb_writew(epio, MUSB_RXCSR, csr);
+		}
+	}
+
+	tdbit = 1 << cppi41_channel->port_num;
+	if (is_tx)
+		tdbit <<= 16;
+
+	do {
+		musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
+		ret = dmaengine_terminate_all(cppi41_channel->dc);
+	} while (ret == -EAGAIN);
+
+	musb_writel(musb->ctrl_base, USB_TDOWN, tdbit);
+
+	if (is_tx) {
+		csr = musb_readw(epio, MUSB_TXCSR);
+		if (csr & MUSB_TXCSR_TXPKTRDY) {
+			csr |= MUSB_TXCSR_FLUSHFIFO;
+			musb_writew(epio, MUSB_TXCSR, csr);
+		}
+	}
+
+	cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
+	return 0;
+}
+
+static void cppi41_release_all_dma_chans(struct cppi41_dma_controller *ctrl)
+{
+	struct dma_chan *dc;
+	int i;
+
+	for (i = 0; i < MUSB_DMA_NUM_CHANNELS; i++) {
+		dc = ctrl->tx_channel[i].dc;
+		if (dc)
+			dma_release_channel(dc);
+		dc = ctrl->rx_channel[i].dc;
+		if (dc)
+			dma_release_channel(dc);
+	}
+}
+
+static void cppi41_dma_controller_stop(struct cppi41_dma_controller *controller)
+{
+	cppi41_release_all_dma_chans(controller);
+}
+
+static int cppi41_dma_controller_start(struct cppi41_dma_controller *controller)
+{
+	struct musb *musb = controller->musb;
+	struct device *dev = musb->controller;
+	struct device_node *np = dev->of_node;
+	struct cppi41_dma_channel *cppi41_channel;
+	int count;
+	int i;
+	int ret;
+
+	count = of_property_count_strings(np, "dma-names");
+	if (count < 0)
+		return count;
+
+	for (i = 0; i < count; i++) {
+		struct dma_chan *dc;
+		struct dma_channel *musb_dma;
+		const char *str;
+		unsigned is_tx;
+		unsigned int port;
+
+		ret = of_property_read_string_index(np, "dma-names", i, &str);
+		if (ret)
+			goto err;
+		if (!strncmp(str, "tx", 2))
+			is_tx = 1;
+		else if (!strncmp(str, "rx", 2))
+			is_tx = 0;
+		else {
+			dev_err(dev, "Wrong dmatype %s\n", str);
+			goto err;
+		}
+		ret = kstrtouint(str + 2, 0, &port);
+		if (ret)
+			goto err;
+
+		if (port > MUSB_DMA_NUM_CHANNELS || !port)
+			goto err;
+		if (is_tx)
+			cppi41_channel = &controller->tx_channel[port - 1];
+		else
+			cppi41_channel = &controller->rx_channel[port - 1];
+
+		cppi41_channel->controller = controller;
+		cppi41_channel->port_num = port;
+		cppi41_channel->is_tx = is_tx;
+
+		musb_dma = &cppi41_channel->channel;
+		musb_dma->private_data = cppi41_channel;
+		musb_dma->status = MUSB_DMA_STATUS_FREE;
+		musb_dma->max_len = SZ_4M;
+
+		dc = dma_request_slave_channel(dev, str);
+		if (!dc) {
+			dev_err(dev, "Falied to request %s.\n", str);
+			goto err;
+		}
+		cppi41_channel->dc = dc;
+	}
+	return 0;
+err:
+	cppi41_release_all_dma_chans(controller);
+	return -EINVAL;
+}
+
+void dma_controller_destroy(struct dma_controller *c)
+{
+	struct cppi41_dma_controller *controller = container_of(c,
+			struct cppi41_dma_controller, controller);
+
+	cppi41_dma_controller_stop(controller);
+	kfree(controller);
+}
+
+struct dma_controller *dma_controller_create(struct musb *musb,
+					void __iomem *base)
+{
+	struct cppi41_dma_controller *controller;
+	int ret;
+
+	if (!musb->controller->of_node) {
+		dev_err(musb->controller, "Need DT for the DMA engine.\n");
+		return NULL;
+	}
+
+	controller = kzalloc(sizeof(*controller), GFP_KERNEL);
+	if (!controller)
+		goto kzalloc_fail;
+
+	controller->musb = musb;
+
+	controller->controller.channel_alloc = cppi41_dma_channel_allocate;
+	controller->controller.channel_release = cppi41_dma_channel_release;
+	controller->controller.channel_program = cppi41_dma_channel_program;
+	controller->controller.channel_abort = cppi41_dma_channel_abort;
+	controller->controller.is_compatible = cppi41_is_compatible;
+
+	ret = cppi41_dma_controller_start(controller);
+	if (ret)
+		goto plat_get_fail;
+	return &controller->controller;
+
+plat_get_fail:
+	kfree(controller);
+kzalloc_fail:
+	return NULL;
+}
diff --git a/drivers/usb/musb/musb_dma.h b/drivers/usb/musb/musb_dma.h
index c8e67fd..1345a4f 100644
--- a/drivers/usb/musb/musb_dma.h
+++ b/drivers/usb/musb/musb_dma.h
@@ -68,7 +68,7 @@ struct musb_hw_ep;
 #define	is_dma_capable()	(1)
 #endif
 
-#ifdef CONFIG_USB_TI_CPPI_DMA
+#if defined(CONFIG_USB_TI_CPPI_DMA) || defined(CONFIG_USB_TI_CPPI41_DMA)
 #define	is_cppi_enabled()	1
 #else
 #define	is_cppi_enabled()	0