USB: imx21-hcd accept arbitary transfer buffer alignement.

The hardware can only do DMA to 4 byte aligned addresses.
When this requirement is not met use PIO or a bounce buffer.

PIO is used when the buffer is small enough to directly
use the hardware data memory (2*maxpacket).

A bounce buffer is used for larger transfers.

Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 169 insertions, 35 deletions

diff --git a/drivers/usb/host/imx21-hcd.c b/drivers/usb/host/imx21-hcd.c
index 890a41ccc5cd..dd132eb7fee7 100644
--- a/drivers/usb/host/imx21-hcd.c
+++ b/drivers/usb/host/imx21-hcd.c
@@ -57,6 +57,7 @@
 #include <linux/slab.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/dma-mapping.h>
 
 #include "imx21-hcd.h"
 
@@ -136,9 +137,18 @@ static int imx21_hc_get_frame(struct usb_hcd *hcd)
         return wrap_frame(readl(imx21->regs + USBH_FRMNUB));
 }
 
+static inline bool unsuitable_for_dma(dma_addr_t addr)
+{
+        return (addr & 3) != 0;
+}
 
 #include "imx21-dbg.c"
 
+static void nonisoc_urb_completed_for_etd(
+        struct imx21 *imx21, struct etd_priv *etd, int status);
+static void schedule_nonisoc_etd(struct imx21 *imx21, struct urb *urb);
+static void free_dmem(struct imx21 *imx21, struct etd_priv *etd);
+
 /* =========================================== */
 /* ETD management                               */
 /* ===========================================  */
@@ -185,7 +195,8 @@ static void reset_etd(struct imx21 *imx21, int num)
                 etd_writel(imx21, num, i, 0);
         etd->urb = NULL;
         etd->ep = NULL;
-        etd->td = NULL;;
+        etd->td = NULL;
+        etd->bounce_buffer = NULL;
 }
 
 static void free_etd(struct imx21 *imx21, int num)
@@ -221,26 +232,94 @@ static void setup_etd_dword0(struct imx21 *imx21,
                 ((u32) maxpacket << DW0_MAXPKTSIZ));
 }
 
-static void activate_etd(struct imx21 *imx21,
-        int etd_num, dma_addr_t dma, u8 dir)
+/**
+ * Copy buffer to data controller data memory.
+ * We cannot use memcpy_toio() because the hardware requires 32bit writes
+ */
+static void copy_to_dmem(
+        struct imx21 *imx21, int dmem_offset, void *src, int count)
+{
+        void __iomem *dmem = imx21->regs + USBOTG_DMEM + dmem_offset;
+        u32 word = 0;
+        u8 *p = src;
+        int byte = 0;
+        int i;
+
+        for (i = 0; i < count; i++) {
+                byte = i % 4;
+                word += (*p++ << (byte * 8));
+                if (byte == 3) {
+                        writel(word, dmem);
+                        dmem += 4;
+                        word = 0;
+                }
+        }
+
+        if (count && byte != 3)
+                writel(word, dmem);
+}
+
+static void activate_etd(struct imx21 *imx21, int etd_num, u8 dir)
 {
         u32 etd_mask = 1 << etd_num;
         struct etd_priv *etd = &imx21->etd[etd_num];
 
+        if (etd->dma_handle && unsuitable_for_dma(etd->dma_handle)) {
+                /* For non aligned isoc the condition below is always true */
+                if (etd->len <= etd->dmem_size) {
+                        /* Fits into data memory, use PIO */
+                        if (dir != TD_DIR_IN) {
+                                copy_to_dmem(imx21,
+                                                etd->dmem_offset,
+                                                etd->cpu_buffer, etd->len);
+                        }
+                        etd->dma_handle = 0;
+
+                } else {
+                        /* Too big for data memory, use bounce buffer */
+                        enum dma_data_direction dmadir;
+
+                        if (dir == TD_DIR_IN) {
+                                dmadir = DMA_FROM_DEVICE;
+                                etd->bounce_buffer = kmalloc(etd->len,
+                                                                GFP_ATOMIC);
+                        } else {
+                                dmadir = DMA_TO_DEVICE;
+                                etd->bounce_buffer = kmemdup(etd->cpu_buffer,
+                                                                etd->len,
+                                                                GFP_ATOMIC);
+                        }
+                        if (!etd->bounce_buffer) {
+                                dev_err(imx21->dev, "failed bounce alloc\n");
+                                goto err_bounce_alloc;
+                        }
+
+                        etd->dma_handle =
+                                dma_map_single(imx21->dev,
+                                                etd->bounce_buffer,
+                                                etd->len,
+                                                dmadir);
+                        if (dma_mapping_error(imx21->dev, etd->dma_handle)) {
+                                dev_err(imx21->dev, "failed bounce map\n");
+                                goto err_bounce_map;
+                        }
+                }
+        }
+
         clear_toggle_bit(imx21, USBH_ETDDONESTAT, etd_mask);
         set_register_bits(imx21, USBH_ETDDONEEN, etd_mask);
         clear_toggle_bit(imx21, USBH_XFILLSTAT, etd_mask);
         clear_toggle_bit(imx21, USBH_YFILLSTAT, etd_mask);
 
-        if (dma) {
+        if (etd->dma_handle) {
                 set_register_bits(imx21, USB_ETDDMACHANLCLR, etd_mask);
                 clear_toggle_bit(imx21, USBH_XBUFSTAT, etd_mask);
                 clear_toggle_bit(imx21, USBH_YBUFSTAT, etd_mask);
-                writel(dma, imx21->regs + USB_ETDSMSA(etd_num));
+                writel(etd->dma_handle, imx21->regs + USB_ETDSMSA(etd_num));
                 set_register_bits(imx21, USB_ETDDMAEN, etd_mask);
         } else {
                 if (dir != TD_DIR_IN) {
-                        /* need to set for ZLP */
+                        /* need to set for ZLP and PIO */
                         set_toggle_bit(imx21, USBH_XFILLSTAT, etd_mask);
                         set_toggle_bit(imx21, USBH_YFILLSTAT, etd_mask);
                 }
@@ -263,6 +342,14 @@ static void activate_etd(struct imx21 *imx21,
 
         etd->active_count = 1;
         writel(etd_mask, imx21->regs + USBH_ETDENSET);
+        return;
+
+err_bounce_map:
+        kfree(etd->bounce_buffer);
+
+err_bounce_alloc:
+        free_dmem(imx21, etd);
+        nonisoc_urb_completed_for_etd(imx21, etd, -ENOMEM);
 }
 
 /* ===========================================  */
@@ -325,7 +412,7 @@ static void activate_queued_etd(struct imx21 *imx21,
 
         etd->dmem_offset = dmem_offset;
         urb_priv->active = 1;
-        activate_etd(imx21, etd_num, etd->dma_handle, dir);
+        activate_etd(imx21, etd_num, dir);
 }
 
 static void free_dmem(struct imx21 *imx21, struct etd_priv *etd)
@@ -385,7 +472,6 @@ static void free_epdmem(struct imx21 *imx21, struct usb_host_endpoint *ep)
 /* ===========================================  */
 /* End handling                                 */
 /* ===========================================  */
-static void schedule_nonisoc_etd(struct imx21 *imx21, struct urb *urb);
 
 /* Endpoint now idle - release it's ETD(s) or asssign to queued request */
 static void ep_idle(struct imx21 *imx21, struct ep_priv *ep_priv)
@@ -448,6 +534,24 @@ __acquires(imx21->lock)
                 ep_idle(imx21, ep_priv);
 }
 
+static void nonisoc_urb_completed_for_etd(
+        struct imx21 *imx21, struct etd_priv *etd, int status)
+{
+        struct usb_host_endpoint *ep = etd->ep;
+
+        urb_done(imx21->hcd, etd->urb, status);
+        etd->urb = NULL;
+
+        if (!list_empty(&ep->urb_list)) {
+                struct urb *urb = list_first_entry(
+                                        &ep->urb_list, struct urb, urb_list);
+
+                dev_vdbg(imx21->dev, "next URB %p\n", urb);
+                schedule_nonisoc_etd(imx21, urb);
+        }
+}
+
+
 /* ===========================================  */
 /* ISOC Handling ...                            */
 /* ===========================================  */
@@ -500,6 +604,8 @@ too_late:
                 etd->ep = td->ep;
                 etd->urb = td->urb;
                 etd->len = td->len;
+                etd->dma_handle = td->dma_handle;
+                etd->cpu_buffer = td->cpu_buffer;
 
                 debug_isoc_submitted(imx21, cur_frame, td);
 
@@ -513,16 +619,17 @@ too_late:
                         (TD_NOTACCESSED << DW3_COMPCODE0) |
                         (td->len << DW3_PKTLEN0));
 
-                activate_etd(imx21, etd_num, td->data, dir);
+                activate_etd(imx21, etd_num, dir);
         }
 }
 
-static void isoc_etd_done(struct usb_hcd *hcd, struct urb *urb, int etd_num)
+static void isoc_etd_done(struct usb_hcd *hcd, int etd_num)
 {
         struct imx21 *imx21 = hcd_to_imx21(hcd);
         int etd_mask = 1 << etd_num;
-        struct urb_priv *urb_priv = urb->hcpriv;
         struct etd_priv *etd = imx21->etd + etd_num;
+        struct urb *urb = etd->urb;
+        struct urb_priv *urb_priv = urb->hcpriv;
         struct td *td = etd->td;
         struct usb_host_endpoint *ep = etd->ep;
         int isoc_index = td->isoc_index;
@@ -556,8 +663,13 @@ static void isoc_etd_done(struct usb_hcd *hcd, struct urb *urb, int etd_num)
                         bytes_xfrd, td->len, urb, etd_num, isoc_index);
         }
 
-        if (dir_in)
+        if (dir_in) {
                 clear_toggle_bit(imx21, USBH_XFILLSTAT, etd_mask);
+                if (!etd->dma_handle)
+                        memcpy_fromio(etd->cpu_buffer,
+                                imx21->regs + USBOTG_DMEM + etd->dmem_offset,
+                                bytes_xfrd);
+        }
 
         urb->actual_length += bytes_xfrd;
         urb->iso_frame_desc[isoc_index].actual_length = bytes_xfrd;
@@ -716,12 +828,14 @@ static int imx21_hc_urb_enqueue_isoc(struct usb_hcd *hcd,
         /* set up transfers */
         td = urb_priv->isoc_td;
         for (i = 0; i < urb->number_of_packets; i++, td++) {
+                unsigned int offset = urb->iso_frame_desc[i].offset;
                 td->ep = ep;
                 td->urb = urb;
                 td->len = urb->iso_frame_desc[i].length;
                 td->isoc_index = i;
                 td->frame = wrap_frame(urb->start_frame + urb->interval * i);
-                td->data = urb->transfer_dma + urb->iso_frame_desc[i].offset;
+                td->dma_handle = urb->transfer_dma + offset;
+                td->cpu_buffer = urb->transfer_buffer + offset;
                 list_add_tail(&td->list, &ep_priv->td_list);
         }
 
@@ -812,13 +926,15 @@ static void schedule_nonisoc_etd(struct imx21 *imx21, struct urb *urb)
         if (usb_pipecontrol(pipe) && (state != US_CTRL_DATA)) {
                 if (state == US_CTRL_SETUP) {
                         dir = TD_DIR_SETUP;
+                        if (unsuitable_for_dma(urb->setup_dma))
+                                unmap_urb_setup_for_dma(imx21->hcd, urb);
                         etd->dma_handle = urb->setup_dma;
+                        etd->cpu_buffer = urb->setup_packet;
                         bufround = 0;
                         count = 8;
                         datatoggle = TD_TOGGLE_DATA0;
                 } else {        /* US_CTRL_ACK */
                         dir = usb_pipeout(pipe) ? TD_DIR_IN : TD_DIR_OUT;
-                        etd->dma_handle = urb->transfer_dma;
                         bufround = 0;
                         count = 0;
                         datatoggle = TD_TOGGLE_DATA1;
@@ -826,7 +942,11 @@ static void schedule_nonisoc_etd(struct imx21 *imx21, struct urb *urb)
         } else {
                 dir = usb_pipeout(pipe) ? TD_DIR_OUT : TD_DIR_IN;
                 bufround = (dir == TD_DIR_IN) ? 1 : 0;
+                if (unsuitable_for_dma(urb->transfer_dma))
+                        unmap_urb_for_dma(imx21->hcd, urb);
+
                 etd->dma_handle = urb->transfer_dma;
+                etd->cpu_buffer = urb->transfer_buffer;
                 if (usb_pipebulk(pipe) && (state == US_BULK0))
                         count = 0;
                 else
@@ -901,14 +1021,15 @@ static void schedule_nonisoc_etd(struct imx21 *imx21, struct urb *urb)
         /* enable the ETD to kick off transfer */
         dev_vdbg(imx21->dev, "Activating etd %d for %d bytes %s\n",
                 etd_num, count, dir != TD_DIR_IN ? "out" : "in");
-        activate_etd(imx21, etd_num, etd->dma_handle, dir);
+        activate_etd(imx21, etd_num, dir);
 
 }
 
-static void nonisoc_etd_done(struct usb_hcd *hcd, struct urb *urb, int etd_num)
+static void nonisoc_etd_done(struct usb_hcd *hcd, int etd_num)
 {
         struct imx21 *imx21 = hcd_to_imx21(hcd);
         struct etd_priv *etd = &imx21->etd[etd_num];
+        struct urb *urb = etd->urb;
         u32 etd_mask = 1 << etd_num;
         struct urb_priv *urb_priv = urb->hcpriv;
         int dir;
@@ -930,7 +1051,20 @@ static void nonisoc_etd_done(struct usb_hcd *hcd, struct urb *urb, int etd_num)
         if (dir == TD_DIR_IN) {
                 clear_toggle_bit(imx21, USBH_XFILLSTAT, etd_mask);
                 clear_toggle_bit(imx21, USBH_YFILLSTAT, etd_mask);
+
+                if (etd->bounce_buffer) {
+                        memcpy(etd->cpu_buffer, etd->bounce_buffer, bytes_xfrd);
+                        dma_unmap_single(imx21->dev,
+                                etd->dma_handle, etd->len, DMA_FROM_DEVICE);
+                } else if (!etd->dma_handle && bytes_xfrd) {/* PIO */
+                        memcpy_fromio(etd->cpu_buffer,
+                                imx21->regs + USBOTG_DMEM + etd->dmem_offset,
+                                bytes_xfrd);
+                }
         }
+
+        kfree(etd->bounce_buffer);
+        etd->bounce_buffer = NULL;
         free_dmem(imx21, etd);
 
         urb->error_count = 0;
@@ -988,24 +1122,15 @@ static void nonisoc_etd_done(struct usb_hcd *hcd, struct urb *urb, int etd_num)
                 break;
         }
 
-        if (!etd_done) {
+        if (etd_done)
+                nonisoc_urb_completed_for_etd(imx21, etd, cc_to_error[cc]);
+        else {
                 dev_vdbg(imx21->dev, "next state=%d\n", urb_priv->state);
                 schedule_nonisoc_etd(imx21, urb);
-        } else {
-                struct usb_host_endpoint *ep = urb->ep;
-
-                urb_done(hcd, urb, cc_to_error[cc]);
-                etd->urb = NULL;
-
-                if (!list_empty(&ep->urb_list)) {
-                        urb = list_first_entry(&ep->urb_list,
-                                struct urb, urb_list);
-                        dev_vdbg(imx21->dev, "next URB %p\n", urb);
-                        schedule_nonisoc_etd(imx21, urb);
-                }
         }
 }
 
+
 static struct ep_priv *alloc_ep(void)
 {
         int i;
@@ -1146,9 +1271,13 @@ static int imx21_hc_urb_dequeue(struct usb_hcd *hcd, struct urb *urb,
         } else if (urb_priv->active) {
                 int etd_num = ep_priv->etd[0];
                 if (etd_num != -1) {
+                        struct etd_priv *etd = &imx21->etd[etd_num];
+
                         disactivate_etd(imx21, etd_num);
-                        free_dmem(imx21, &imx21->etd[etd_num]);
-                        imx21->etd[etd_num].urb = NULL;
+                        free_dmem(imx21, etd);
+                        etd->urb = NULL;
+                        kfree(etd->bounce_buffer);
+                        etd->bounce_buffer = NULL;
                 }
         }
 
@@ -1248,9 +1377,9 @@ static void process_etds(struct usb_hcd *hcd, struct imx21 *imx21, int sof)
                 }
 
                 if (usb_pipeisoc(etd->urb->pipe))
-                        isoc_etd_done(hcd, etd->urb, etd_num);
+                        isoc_etd_done(hcd, etd_num);
                 else
-                        nonisoc_etd_done(hcd, etd->urb, etd_num);
+                        nonisoc_etd_done(hcd, etd_num);
         }
 
         /* only enable SOF interrupt if it may be needed for the kludge */
@@ -1718,6 +1847,7 @@ static int imx21_probe(struct platform_device *pdev)
         }
 
         imx21 = hcd_to_imx21(hcd);
+        imx21->hcd = hcd;
         imx21->dev = &pdev->dev;
         imx21->pdata = pdev->dev.platform_data;
         if (!imx21->pdata)
diff --git a/drivers/usb/host/imx21-hcd.h b/drivers/usb/host/imx21-hcd.h
index 1b0d913780a5..87b29fd971b4 100644
--- a/drivers/usb/host/imx21-hcd.h
+++ b/drivers/usb/host/imx21-hcd.h
@@ -250,6 +250,7 @@
 #define USBCTRL_USB_BYP                 (1 << 2)
 #define USBCTRL_HOST1_TXEN_OE           (1 << 1)
 
+#define USBOTG_DMEM             0x1000
 
 /* Values in TD blocks */
 #define TD_DIR_SETUP        0
@@ -346,8 +347,8 @@ struct td {
         struct list_head list;
         struct urb *urb;
         struct usb_host_endpoint *ep;
-        dma_addr_t data;
-        unsigned long buf_addr;
+        dma_addr_t dma_handle;
+        void *cpu_buffer;
         int len;
         int frame;
         int isoc_index;
@@ -360,6 +361,8 @@ struct etd_priv {
         struct td *td;
         struct list_head queue;
         dma_addr_t dma_handle;
+        void *cpu_buffer;
+        void *bounce_buffer;
         int alloc;
         int len;
         int dmem_size;
@@ -412,6 +415,7 @@ struct debug_isoc_trace {
 struct imx21 {
         spinlock_t lock;
         struct device *dev;
+        struct usb_hcd *hcd;
         struct mx21_usbh_platform_data *pdata;
         struct list_head dmem_list;
         struct list_head queue_for_etd; /* eps queued due to etd shortage */