2 files changed, 278 insertions, 135 deletions

diff --git a/drivers/firewire/Kconfig b/drivers/firewire/Kconfig
index 40a222e19b2..68f942cb30f 100644
--- a/drivers/firewire/Kconfig
+++ b/drivers/firewire/Kconfig
@@ -19,7 +19,7 @@ config FIREWIRE
 
 config FIREWIRE_OHCI
 	tristate "OHCI-1394 controllers"
-	depends on PCI && FIREWIRE
+	depends on PCI && FIREWIRE && MMU
 	help
 	  Enable this driver if you have a FireWire controller based
 	  on the OHCI specification.  For all practical purposes, this
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index e3c8b60bd86..be0a01d8cef 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -40,6 +40,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/time.h>
+#include <linux/vmalloc.h>
 
 #include <asm/byteorder.h>
 #include <asm/page.h>
@@ -80,17 +81,23 @@ struct descriptor {
 #define COMMAND_PTR(regs)	((regs) + 12)
 #define CONTEXT_MATCH(regs)	((regs) + 16)
 
-struct ar_buffer {
-	struct descriptor descriptor;
-	struct ar_buffer *next;
-	__le32 data[0];
-};
+#define AR_BUFFER_SIZE	(32*1024)
+#define AR_BUFFERS_MIN	DIV_ROUND_UP(AR_BUFFER_SIZE, PAGE_SIZE)
+/* we need at least two pages for proper list management */
+#define AR_BUFFERS	(AR_BUFFERS_MIN >= 2 ? AR_BUFFERS_MIN : 2)
+
+#define MAX_ASYNC_PAYLOAD	4096
+#define MAX_AR_PACKET_SIZE	(16 + MAX_ASYNC_PAYLOAD + 4)
+#define AR_WRAPAROUND_PAGES	DIV_ROUND_UP(MAX_AR_PACKET_SIZE, PAGE_SIZE)
 
 struct ar_context {
 	struct fw_ohci *ohci;
-	struct ar_buffer *current_buffer;
-	struct ar_buffer *last_buffer;
+	struct page *pages[AR_BUFFERS];
+	void *buffer;
+	struct descriptor *descriptors;
+	dma_addr_t descriptors_bus;
 	void *pointer;
+	unsigned int last_buffer_index;
 	u32 regs;
 	struct tasklet_struct tasklet;
 };
@@ -594,59 +601,155 @@ static int ohci_update_phy_reg(struct fw_card *card, int addr,
 	return ret;
 }
 
-static void ar_context_link_page(struct ar_context *ctx,
-				 struct ar_buffer *ab, dma_addr_t ab_bus)
+static inline dma_addr_t ar_buffer_bus(struct ar_context *ctx, unsigned int i)
+{
+	return page_private(ctx->pages[i]);
+}
+
+static void ar_context_link_page(struct ar_context *ctx, unsigned int index)
 {
-	size_t offset;
+	struct descriptor *d;
 
-	ab->next = NULL;
-	memset(&ab->descriptor, 0, sizeof(ab->descriptor));
-	ab->descriptor.control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
-						    DESCRIPTOR_STATUS |
-						    DESCRIPTOR_BRANCH_ALWAYS);
-	offset = offsetof(struct ar_buffer, data);
-	ab->descriptor.req_count      = cpu_to_le16(PAGE_SIZE - offset);
-	ab->descriptor.data_address   = cpu_to_le32(ab_bus + offset);
-	ab->descriptor.res_count      = cpu_to_le16(PAGE_SIZE - offset);
-	ab->descriptor.branch_address = 0;
+	d = &ctx->descriptors[index];
+	d->branch_address  &= cpu_to_le32(~0xf);
+	d->res_count       =  cpu_to_le16(PAGE_SIZE);
+	d->transfer_status =  0;
 
 	wmb(); /* finish init of new descriptors before branch_address update */
-	ctx->last_buffer->descriptor.branch_address = cpu_to_le32(ab_bus | 1);
-	ctx->last_buffer->next = ab;
-	ctx->last_buffer = ab;
+	d = &ctx->descriptors[ctx->last_buffer_index];
+	d->branch_address  |= cpu_to_le32(1);
+
+	ctx->last_buffer_index = index;
 
 	reg_write(ctx->ohci, CONTROL_SET(ctx->regs), CONTEXT_WAKE);
 	flush_writes(ctx->ohci);
 }
 
-static int ar_context_add_page(struct ar_context *ctx)
+static void ar_context_release(struct ar_context *ctx)
 {
-	struct device *dev = ctx->ohci->card.device;
-	struct ar_buffer *ab;
-	dma_addr_t uninitialized_var(ab_bus);
+	unsigned int i;
 
-	ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);
-	if (ab == NULL)
-		return -ENOMEM;
+	if (ctx->descriptors)
+		dma_free_coherent(ctx->ohci->card.device,
+				  AR_BUFFERS * sizeof(struct descriptor),
+				  ctx->descriptors, ctx->descriptors_bus);
 
-	ar_context_link_page(ctx, ab, ab_bus);
+	if (ctx->buffer)
+		vm_unmap_ram(ctx->buffer, AR_BUFFERS + AR_WRAPAROUND_PAGES);
 
-	return 0;
+	for (i = 0; i < AR_BUFFERS; i++)
+		if (ctx->pages[i]) {
+			dma_unmap_page(ctx->ohci->card.device,
+				       ar_buffer_bus(ctx, i),
+				       PAGE_SIZE, DMA_FROM_DEVICE);
+			__free_page(ctx->pages[i]);
+		}
 }
 
-static void ar_context_release(struct ar_context *ctx)
+static void ar_context_abort(struct ar_context *ctx, const char *error_msg)
 {
-	struct ar_buffer *ab, *ab_next;
-	size_t offset;
-	dma_addr_t ab_bus;
+	if (reg_read(ctx->ohci, CONTROL_CLEAR(ctx->regs)) & CONTEXT_RUN) {
+		reg_write(ctx->ohci, CONTROL_CLEAR(ctx->regs), CONTEXT_RUN);
+		flush_writes(ctx->ohci);
 
-	for (ab = ctx->current_buffer; ab; ab = ab_next) {
-		ab_next = ab->next;
-		offset = offsetof(struct ar_buffer, data);
-		ab_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
-		dma_free_coherent(ctx->ohci->card.device, PAGE_SIZE,
-				  ab, ab_bus);
+		fw_error("AR error: %s; DMA stopped\n", error_msg);
 	}
+	/* FIXME: restart? */
+}
+
+static inline unsigned int ar_next_buffer_index(unsigned int index)
+{
+	return (index + 1) % AR_BUFFERS;
+}
+
+static inline unsigned int ar_prev_buffer_index(unsigned int index)
+{
+	return (index - 1 + AR_BUFFERS) % AR_BUFFERS;
+}
+
+static inline unsigned int ar_first_buffer_index(struct ar_context *ctx)
+{
+	return ar_next_buffer_index(ctx->last_buffer_index);
+}
+
+/*
+ * We search for the buffer that contains the last AR packet DMA data written
+ * by the controller.
+ */
+static unsigned int ar_search_last_active_buffer(struct ar_context *ctx,
+						 unsigned int *buffer_offset)
+{
+	unsigned int i, next_i, last = ctx->last_buffer_index;
+	__le16 res_count, next_res_count;
+
+	i = ar_first_buffer_index(ctx);
+	res_count = ACCESS_ONCE(ctx->descriptors[i].res_count);
+
+	/* A buffer that is not yet completely filled must be the last one. */
+	while (i != last && res_count == 0) {
+
+		/* Peek at the next descriptor. */
+		next_i = ar_next_buffer_index(i);
+		rmb(); /* read descriptors in order */
+		next_res_count = ACCESS_ONCE(
+				ctx->descriptors[next_i].res_count);
+		/*
+		 * If the next descriptor is still empty, we must stop at this
+		 * descriptor.
+		 */
+		if (next_res_count == cpu_to_le16(PAGE_SIZE)) {
+			/*
+			 * The exception is when the DMA data for one packet is
+			 * split over three buffers; in this case, the middle
+			 * buffer's descriptor might be never updated by the
+			 * controller and look still empty, and we have to peek
+			 * at the third one.
+			 */
+			if (MAX_AR_PACKET_SIZE > PAGE_SIZE && i != last) {
+				next_i = ar_next_buffer_index(next_i);
+				rmb();
+				next_res_count = ACCESS_ONCE(
+					ctx->descriptors[next_i].res_count);
+				if (next_res_count != cpu_to_le16(PAGE_SIZE))
+					goto next_buffer_is_active;
+			}
+
+			break;
+		}
+
+next_buffer_is_active:
+		i = next_i;
+		res_count = next_res_count;
+	}
+
+	rmb(); /* read res_count before the DMA data */
+
+	*buffer_offset = PAGE_SIZE - le16_to_cpu(res_count);
+	if (*buffer_offset > PAGE_SIZE) {
+		*buffer_offset = 0;
+		ar_context_abort(ctx, "corrupted descriptor");
+	}
+
+	return i;
+}
+
+static void ar_sync_buffers_for_cpu(struct ar_context *ctx,
+				    unsigned int end_buffer_index,
+				    unsigned int end_buffer_offset)
+{
+	unsigned int i;
+
+	i = ar_first_buffer_index(ctx);
+	while (i != end_buffer_index) {
+		dma_sync_single_for_cpu(ctx->ohci->card.device,
+					ar_buffer_bus(ctx, i),
+					PAGE_SIZE, DMA_FROM_DEVICE);
+		i = ar_next_buffer_index(i);
+	}
+	if (end_buffer_offset > 0)
+		dma_sync_single_for_cpu(ctx->ohci->card.device,
+					ar_buffer_bus(ctx, i),
+					end_buffer_offset, DMA_FROM_DEVICE);
 }
 
 #if defined(CONFIG_PPC_PMAC) && defined(CONFIG_PPC32)
@@ -689,6 +792,10 @@ static __le32 *handle_ar_packet(struct ar_context *ctx, __le32 *buffer)
 		p.header[3] = cond_le32_to_cpu(buffer[3]);
 		p.header_length = 16;
 		p.payload_length = p.header[3] >> 16;
+		if (p.payload_length > MAX_ASYNC_PAYLOAD) {
+			ar_context_abort(ctx, "invalid packet length");
+			return NULL;
+		}
 		break;
 
 	case TCODE_WRITE_RESPONSE:
@@ -699,9 +806,8 @@ static __le32 *handle_ar_packet(struct ar_context *ctx, __le32 *buffer)
 		break;
 
 	default:
-		/* FIXME: Stop context, discard everything, and restart? */
-		p.header_length = 0;
-		p.payload_length = 0;
+		ar_context_abort(ctx, "invalid tcode");
+		return NULL;
 	}
 
 	p.payload = (void *) buffer + p.header_length;
@@ -751,121 +857,152 @@ static __le32 *handle_ar_packet(struct ar_context *ctx, __le32 *buffer)
 	return buffer + length + 1;
 }
 
+static void *handle_ar_packets(struct ar_context *ctx, void *p, void *end)
+{
+	void *next;
+
+	while (p < end) {
+		next = handle_ar_packet(ctx, p);
+		if (!next)
+			return p;
+		p = next;
+	}
+
+	return p;
+}
+
+static void ar_recycle_buffers(struct ar_context *ctx, unsigned int end_buffer)
+{
+	unsigned int i;
+
+	i = ar_first_buffer_index(ctx);
+	while (i != end_buffer) {
+		dma_sync_single_for_device(ctx->ohci->card.device,
+					   ar_buffer_bus(ctx, i),
+					   PAGE_SIZE, DMA_FROM_DEVICE);
+		ar_context_link_page(ctx, i);
+		i = ar_next_buffer_index(i);
+	}
+}
+
 static void ar_context_tasklet(unsigned long data)
 {
 	struct ar_context *ctx = (struct ar_context *)data;
-	struct ar_buffer *ab;
-	struct descriptor *d;
-	void *buffer, *end;
-	__le16 res_count;
+	unsigned int end_buffer_index, end_buffer_offset;
+	void *p, *end;
 
-	ab = ctx->current_buffer;
-	d = &ab->descriptor;
+	p = ctx->pointer;
+	if (!p)
+		return;
 
-	res_count = ACCESS_ONCE(d->res_count);
-	if (res_count == 0) {
-		size_t size, size2, rest, pktsize, size3, offset;
-		dma_addr_t start_bus;
-		void *start;
+	end_buffer_index = ar_search_last_active_buffer(ctx,
+							&end_buffer_offset);
+	ar_sync_buffers_for_cpu(ctx, end_buffer_index, end_buffer_offset);
+	end = ctx->buffer + end_buffer_index * PAGE_SIZE + end_buffer_offset;
 
+	if (end_buffer_index < ar_first_buffer_index(ctx)) {
 		/*
-		 * This descriptor is finished and we may have a
-		 * packet split across this and the next buffer. We
-		 * reuse the page for reassembling the split packet.
+		 * The filled part of the overall buffer wraps around; handle
+		 * all packets up to the buffer end here.  If the last packet
+		 * wraps around, its tail will be visible after the buffer end
+		 * because the buffer start pages are mapped there again.
 		 */
+		void *buffer_end = ctx->buffer + AR_BUFFERS * PAGE_SIZE;
+		p = handle_ar_packets(ctx, p, buffer_end);
+		if (p < buffer_end)
+			goto error;
+		/* adjust p to point back into the actual buffer */
+		p -= AR_BUFFERS * PAGE_SIZE;
+	}
 
-		offset = offsetof(struct ar_buffer, data);
-		start = ab;
-		start_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
-		buffer = ab->data;
-
-		ab = ab->next;
-		d = &ab->descriptor;
-		size = start + PAGE_SIZE - ctx->pointer;
-		/* valid buffer data in the next page */
-		rest = le16_to_cpu(d->req_count) - le16_to_cpu(d->res_count);
-		/* what actually fits in this page */
-		size2 = min(rest, (size_t)PAGE_SIZE - offset - size);
-		memmove(buffer, ctx->pointer, size);
-		memcpy(buffer + size, ab->data, size2);
-
-		while (size > 0) {
-			void *next = handle_ar_packet(ctx, buffer);
-			pktsize = next - buffer;
-			if (pktsize >= size) {
-				/*
-				 * We have handled all the data that was
-				 * originally in this page, so we can now
-				 * continue in the next page.
-				 */
-				buffer = next;
-				break;
-			}
-			/* move the next packet to the start of the buffer */
-			memmove(buffer, next, size + size2 - pktsize);
-			size -= pktsize;
-			/* fill up this page again */
-			size3 = min(rest - size2,
-				    (size_t)PAGE_SIZE - offset - size - size2);
-			memcpy(buffer + size + size2,
-			       (void *) ab->data + size2, size3);
-			size2 += size3;
-		}
-
-		if (rest > 0) {
-			/* handle the packets that are fully in the next page */
-			buffer = (void *) ab->data +
-					(buffer - (start + offset + size));
-			end = (void *) ab->data + rest;
+	p = handle_ar_packets(ctx, p, end);
+	if (p != end) {
+		if (p > end)
+			ar_context_abort(ctx, "inconsistent descriptor");
+		goto error;
+	}
 
-			while (buffer < end)
-				buffer = handle_ar_packet(ctx, buffer);
+	ctx->pointer = p;
+	ar_recycle_buffers(ctx, end_buffer_index);
 
-			ctx->current_buffer = ab;
-			ctx->pointer = end;
+	return;
 
-			ar_context_link_page(ctx, start, start_bus);
-		} else {
-			ctx->pointer = start + PAGE_SIZE;
-		}
-	} else {
-		buffer = ctx->pointer;
-		ctx->pointer = end =
-			(void *) ab + PAGE_SIZE - le16_to_cpu(res_count);
-
-		while (buffer < end)
-			buffer = handle_ar_packet(ctx, buffer);
-	}
+error:
+	ctx->pointer = NULL;
 }
 
 static int ar_context_init(struct ar_context *ctx,
 			   struct fw_ohci *ohci, u32 regs)
 {
-	struct ar_buffer ab;
+	unsigned int i;
+	dma_addr_t dma_addr;
+	struct page *pages[AR_BUFFERS + AR_WRAPAROUND_PAGES];
+	struct descriptor *d;
 
 	ctx->regs        = regs;
 	ctx->ohci        = ohci;
-	ctx->last_buffer = &ab;
 	tasklet_init(&ctx->tasklet, ar_context_tasklet, (unsigned long)ctx);
 
-	ar_context_add_page(ctx);
-	ar_context_add_page(ctx);
-	ctx->current_buffer = ab.next;
-	ctx->pointer = ctx->current_buffer->data;
+	for (i = 0; i < AR_BUFFERS; i++) {
+		ctx->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32);
+		if (!ctx->pages[i])
+			goto out_of_memory;
+		dma_addr = dma_map_page(ohci->card.device, ctx->pages[i],
+					0, PAGE_SIZE, DMA_FROM_DEVICE);
+		if (dma_mapping_error(ohci->card.device, dma_addr)) {
+			__free_page(ctx->pages[i]);
+			ctx->pages[i] = NULL;
+			goto out_of_memory;
+		}
+		set_page_private(ctx->pages[i], dma_addr);
+	}
+
+	for (i = 0; i < AR_BUFFERS; i++)
+		pages[i]              = ctx->pages[i];
+	for (i = 0; i < AR_WRAPAROUND_PAGES; i++)
+		pages[AR_BUFFERS + i] = ctx->pages[i];
+	ctx->buffer = vm_map_ram(pages, AR_BUFFERS + AR_WRAPAROUND_PAGES,
+				 -1, PAGE_KERNEL_RO);
+	if (!ctx->buffer)
+		goto out_of_memory;
+
+	ctx->descriptors =
+		dma_alloc_coherent(ohci->card.device,
+				   AR_BUFFERS * sizeof(struct descriptor),
+				   &ctx->descriptors_bus,
+				   GFP_KERNEL);
+	if (!ctx->descriptors)
+		goto out_of_memory;
+
+	for (i = 0; i < AR_BUFFERS; i++) {
+		d = &ctx->descriptors[i];
+		d->req_count      = cpu_to_le16(PAGE_SIZE);
+		d->control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
+						DESCRIPTOR_STATUS |
+						DESCRIPTOR_BRANCH_ALWAYS);
+		d->data_address   = cpu_to_le32(ar_buffer_bus(ctx, i));
+		d->branch_address = cpu_to_le32(ctx->descriptors_bus +
+			ar_next_buffer_index(i) * sizeof(struct descriptor));
+	}
 
 	return 0;
+
+out_of_memory:
+	ar_context_release(ctx);
+
+	return -ENOMEM;
 }
 
 static void ar_context_run(struct ar_context *ctx)
 {
-	struct ar_buffer *ab = ctx->current_buffer;
-	dma_addr_t ab_bus;
-	size_t offset;
+	unsigned int i;
+
+	for (i = 0; i < AR_BUFFERS; i++)
+		ar_context_link_page(ctx, i);
 
-	offset = offsetof(struct ar_buffer, data);
-	ab_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
+	ctx->pointer = ctx->buffer;
 
-	reg_write(ctx->ohci, COMMAND_PTR(ctx->regs), ab_bus | 1);
+	reg_write(ctx->ohci, COMMAND_PTR(ctx->regs), ctx->descriptors_bus | 1);
 	reg_write(ctx->ohci, CONTROL_SET(ctx->regs), CONTEXT_RUN);
 	flush_writes(ctx->ohci);
 }
@@ -2955,11 +3092,15 @@ static int __devinit pci_probe(struct pci_dev *dev,
 	if (param_quirks)
 		ohci->quirks = param_quirks;
 
-	ar_context_init(&ohci->ar_request_ctx, ohci,
-			OHCI1394_AsReqRcvContextControlSet);
+	err = ar_context_init(&ohci->ar_request_ctx, ohci,
+			      OHCI1394_AsReqRcvContextControlSet);
+	if (err < 0)
+		goto fail_iounmap;
 
-	ar_context_init(&ohci->ar_response_ctx, ohci,
-			OHCI1394_AsRspRcvContextControlSet);
+	err = ar_context_init(&ohci->ar_response_ctx, ohci,
+			      OHCI1394_AsRspRcvContextControlSet);
+	if (err < 0)
+		goto fail_arreq_ctx;
 
 	context_init(&ohci->at_request_ctx, ohci,
 		     OHCI1394_AsReqTrContextControlSet, handle_at_packet);
@@ -3024,7 +3165,9 @@ static int __devinit pci_probe(struct pci_dev *dev,
 	context_release(&ohci->at_response_ctx);
 	context_release(&ohci->at_request_ctx);
 	ar_context_release(&ohci->ar_response_ctx);
+ fail_arreq_ctx:
 	ar_context_release(&ohci->ar_request_ctx);
+ fail_iounmap:
 	pci_iounmap(dev, ohci->registers);
  fail_iomem:
 	pci_release_region(dev, 0);