usb: gadget: udc: renesas_usb3: add support for dedicated DMAC
authorYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tue, 6 Jun 2017 11:24:20 +0000 (20:24 +0900)
committerFelipe Balbi <felipe.balbi@linux.intel.com>
Tue, 13 Jun 2017 10:21:07 +0000 (13:21 +0300)
The USB3.0 peripheral controller on R-Car SoCs has a dedicated DMAC.
The DMAC needs a "PRD table" in system memory and the DMAC can have
four PRD tables. This patch adds support for the DMAC.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
drivers/usb/gadget/udc/renesas_usb3.c

index 5a2d845fb1a68708a3ea27b3822ae8de7afb85df..078f7737ed6f8c551bb753c11620e5b771519fe3 100644 (file)
@@ -9,6 +9,7 @@
  */
 
 #include <linux/delay.h>
+#include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/extcon.h>
 #include <linux/interrupt.h>
@@ -27,6 +28,8 @@
 #define USB3_AXI_INT_ENA       0x00c
 #define USB3_DMA_INT_STA       0x010
 #define USB3_DMA_INT_ENA       0x014
+#define USB3_DMA_CH0_CON(n)    (0x030 + ((n) - 1) * 0x10) /* n = 1 to 4 */
+#define USB3_DMA_CH0_PRD_ADR(n)        (0x034 + ((n) - 1) * 0x10) /* n = 1 to 4 */
 #define USB3_USB_COM_CON       0x200
 #define USB3_USB20_CON         0x204
 #define USB3_USB30_CON         0x208
 /* AXI_INT_ENA and AXI_INT_STA */
 #define AXI_INT_DMAINT         BIT(31)
 #define AXI_INT_EPCINT         BIT(30)
+/* PRD's n = from 1 to 4 */
+#define AXI_INT_PRDEN_CLR_STA_SHIFT(n) (16 + (n) - 1)
+#define AXI_INT_PRDERR_STA_SHIFT(n)    (0 + (n) - 1)
+#define AXI_INT_PRDEN_CLR_STA(n)       (1 << AXI_INT_PRDEN_CLR_STA_SHIFT(n))
+#define AXI_INT_PRDERR_STA(n)          (1 << AXI_INT_PRDERR_STA_SHIFT(n))
+
+/* DMA_INT_ENA and DMA_INT_STA */
+#define DMA_INT(n)             BIT(n)
+
+/* DMA_CH0_CONn */
+#define DMA_CON_PIPE_DIR       BIT(15)         /* 1: In Transfer */
+#define DMA_CON_PIPE_NO_SHIFT  8
+#define DMA_CON_PIPE_NO_MASK   GENMASK(12, DMA_CON_PIPE_NO_SHIFT)
+#define DMA_COM_PIPE_NO(n)     (((n) << DMA_CON_PIPE_NO_SHIFT) & \
+                                        DMA_CON_PIPE_NO_MASK)
+#define DMA_CON_PRD_EN         BIT(0)
 
 /* LCLKSEL */
 #define LCLKSEL_LSEL           BIT(18)
 #define USB3_EP0_BUF_SIZE              8
 #define USB3_MAX_NUM_PIPES             30
 #define USB3_WAIT_US                   3
+#define USB3_DMA_NUM_SETTING_AREA      4
+/*
+ * To avoid double-meaning of "0" (xferred 65536 bytes or received zlp if
+ * buffer size is 65536), this driver uses the maximum size per a entry is
+ * 32768 bytes.
+ */
+#define USB3_DMA_MAX_XFER_SIZE         32768
+#define USB3_DMA_PRD_SIZE              4096
 
 struct renesas_usb3;
+
+/* Physical Region Descriptor Table */
+struct renesas_usb3_prd {
+       u32 word1;
+#define USB3_PRD1_E            BIT(30)         /* the end of chain */
+#define USB3_PRD1_U            BIT(29)         /* completion of transfer */
+#define USB3_PRD1_D            BIT(28)         /* Error occurred */
+#define USB3_PRD1_INT          BIT(27)         /* Interrupt occurred */
+#define USB3_PRD1_LST          BIT(26)         /* Last Packet */
+#define USB3_PRD1_B_INC                BIT(24)
+#define USB3_PRD1_MPS_8                0
+#define USB3_PRD1_MPS_16       BIT(21)
+#define USB3_PRD1_MPS_32       BIT(22)
+#define USB3_PRD1_MPS_64       (BIT(22) | BIT(21))
+#define USB3_PRD1_MPS_512      BIT(23)
+#define USB3_PRD1_MPS_1024     (BIT(23) | BIT(21))
+#define USB3_PRD1_MPS_RESERVED (BIT(23) | BIT(22) | BIT(21))
+#define USB3_PRD1_SIZE_MASK    GENMASK(15, 0)
+
+       u32 bap;
+};
+#define USB3_DMA_NUM_PRD_ENTRIES       (USB3_DMA_PRD_SIZE / \
+                                         sizeof(struct renesas_usb3_prd))
+#define USB3_DMA_MAX_XFER_SIZE_ALL_PRDS        (USB3_DMA_PRD_SIZE / \
+                                        sizeof(struct renesas_usb3_prd) * \
+                                        USB3_DMA_MAX_XFER_SIZE)
+
+struct renesas_usb3_dma {
+       struct renesas_usb3_prd *prd;
+       dma_addr_t prd_dma;
+       int num;        /* Setting area number (from 1 to 4) */
+       bool used;
+};
+
 struct renesas_usb3_request {
        struct usb_request      req;
        struct list_head        queue;
@@ -242,6 +303,7 @@ struct renesas_usb3_request {
 struct renesas_usb3_ep {
        struct usb_ep ep;
        struct renesas_usb3 *usb3;
+       struct renesas_usb3_dma *dma;
        int num;
        char ep_name[USB3_EP_NAME_SIZE];
        struct list_head queue;
@@ -270,6 +332,8 @@ struct renesas_usb3 {
        struct renesas_usb3_ep *usb3_ep;
        int num_usb3_eps;
 
+       struct renesas_usb3_dma dma[USB3_DMA_NUM_SETTING_AREA];
+
        spinlock_t lock;
        int disabled_count;
 
@@ -298,8 +362,18 @@ struct renesas_usb3 {
                     (i) < (usb3)->num_usb3_eps;                \
                     (i)++, usb3_ep = usb3_get_ep(usb3, (i)))
 
+#define usb3_get_dma(usb3, i)  (&(usb3)->dma[i])
+#define usb3_for_each_dma(usb3, dma, i)                                \
+               for ((i) = 0, dma = usb3_get_dma((usb3), (i));  \
+                    (i) < USB3_DMA_NUM_SETTING_AREA;           \
+                    (i)++, dma = usb3_get_dma((usb3), (i)))
+
 static const char udc_name[] = "renesas_usb3";
 
+static bool use_dma = 1;
+module_param(use_dma, bool, 0644);
+MODULE_PARM_DESC(use_dma, "use dedicated DMAC");
+
 static void usb3_write(struct renesas_usb3 *usb3, u32 data, u32 offs)
 {
        iowrite32(data, usb3->reg + offs);
@@ -1060,6 +1134,273 @@ static void usb3_start_pipe0(struct renesas_usb3_ep *usb3_ep,
        usb3_p0_xfer(usb3_ep, usb3_req);
 }
 
+static void usb3_enable_dma_pipen(struct renesas_usb3 *usb3)
+{
+       usb3_set_bit(usb3, PN_CON_DATAIF_EN, USB3_PN_CON);
+}
+
+static void usb3_disable_dma_pipen(struct renesas_usb3 *usb3)
+{
+       usb3_clear_bit(usb3, PN_CON_DATAIF_EN, USB3_PN_CON);
+}
+
+static void usb3_enable_dma_irq(struct renesas_usb3 *usb3, int num)
+{
+       usb3_set_bit(usb3, DMA_INT(num), USB3_DMA_INT_ENA);
+}
+
+static void usb3_disable_dma_irq(struct renesas_usb3 *usb3, int num)
+{
+       usb3_clear_bit(usb3, DMA_INT(num), USB3_DMA_INT_ENA);
+}
+
+static u32 usb3_dma_mps_to_prd_word1(struct renesas_usb3_ep *usb3_ep)
+{
+       switch (usb3_ep->ep.maxpacket) {
+       case 8:
+               return USB3_PRD1_MPS_8;
+       case 16:
+               return USB3_PRD1_MPS_16;
+       case 32:
+               return USB3_PRD1_MPS_32;
+       case 64:
+               return USB3_PRD1_MPS_64;
+       case 512:
+               return USB3_PRD1_MPS_512;
+       case 1024:
+               return USB3_PRD1_MPS_1024;
+       default:
+               return USB3_PRD1_MPS_RESERVED;
+       }
+}
+
+static bool usb3_dma_get_setting_area(struct renesas_usb3_ep *usb3_ep,
+                                     struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+       struct renesas_usb3_dma *dma;
+       int i;
+       bool ret = false;
+
+       if (usb3_req->req.length > USB3_DMA_MAX_XFER_SIZE_ALL_PRDS) {
+               dev_dbg(usb3_to_dev(usb3), "%s: the length is too big (%d)\n",
+                       __func__, usb3_req->req.length);
+               return false;
+       }
+
+       /* The driver doesn't handle zero-length packet via dmac */
+       if (!usb3_req->req.length)
+               return false;
+
+       if (usb3_dma_mps_to_prd_word1(usb3_ep) == USB3_PRD1_MPS_RESERVED)
+               return false;
+
+       usb3_for_each_dma(usb3, dma, i) {
+               if (dma->used)
+                       continue;
+
+               if (usb_gadget_map_request(&usb3->gadget, &usb3_req->req,
+                                          usb3_ep->dir_in) < 0)
+                       break;
+
+               dma->used = true;
+               usb3_ep->dma = dma;
+               ret = true;
+               break;
+       }
+
+       return ret;
+}
+
+static void usb3_dma_put_setting_area(struct renesas_usb3_ep *usb3_ep,
+                                     struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+       int i;
+       struct renesas_usb3_dma *dma;
+
+       usb3_for_each_dma(usb3, dma, i) {
+               if (usb3_ep->dma == dma) {
+                       usb_gadget_unmap_request(&usb3->gadget, &usb3_req->req,
+                                                usb3_ep->dir_in);
+                       dma->used = false;
+                       usb3_ep->dma = NULL;
+                       break;
+               }
+       }
+}
+
+static void usb3_dma_fill_prd(struct renesas_usb3_ep *usb3_ep,
+                             struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3_prd *cur_prd = usb3_ep->dma->prd;
+       u32 remain = usb3_req->req.length;
+       u32 dma = usb3_req->req.dma;
+       u32 len;
+       int i = 0;
+
+       do {
+               len = min_t(u32, remain, USB3_DMA_MAX_XFER_SIZE) &
+                           USB3_PRD1_SIZE_MASK;
+               cur_prd->word1 = usb3_dma_mps_to_prd_word1(usb3_ep) |
+                                USB3_PRD1_B_INC | len;
+               cur_prd->bap = dma;
+               remain -= len;
+               dma += len;
+               if (!remain || (i + 1) < USB3_DMA_NUM_PRD_ENTRIES)
+                       break;
+
+               cur_prd++;
+               i++;
+       } while (1);
+
+       cur_prd->word1 |= USB3_PRD1_E | USB3_PRD1_INT;
+       if (usb3_ep->dir_in)
+               cur_prd->word1 |= USB3_PRD1_LST;
+}
+
+static void usb3_dma_kick_prd(struct renesas_usb3_ep *usb3_ep)
+{
+       struct renesas_usb3_dma *dma = usb3_ep->dma;
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+       u32 dma_con = DMA_COM_PIPE_NO(usb3_ep->num) | DMA_CON_PRD_EN;
+
+       if (usb3_ep->dir_in)
+               dma_con |= DMA_CON_PIPE_DIR;
+
+       wmb();  /* prd entries should be in system memory here */
+
+       usb3_write(usb3, 1 << usb3_ep->num, USB3_DMA_INT_STA);
+       usb3_write(usb3, AXI_INT_PRDEN_CLR_STA(dma->num) |
+                  AXI_INT_PRDERR_STA(dma->num), USB3_AXI_INT_STA);
+
+       usb3_write(usb3, dma->prd_dma, USB3_DMA_CH0_PRD_ADR(dma->num));
+       usb3_write(usb3, dma_con, USB3_DMA_CH0_CON(dma->num));
+       usb3_enable_dma_irq(usb3, usb3_ep->num);
+}
+
+static void usb3_dma_stop_prd(struct renesas_usb3_ep *usb3_ep)
+{
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+       struct renesas_usb3_dma *dma = usb3_ep->dma;
+
+       usb3_disable_dma_irq(usb3, usb3_ep->num);
+       usb3_write(usb3, 0, USB3_DMA_CH0_CON(dma->num));
+}
+
+static int usb3_dma_update_status(struct renesas_usb3_ep *usb3_ep,
+                                 struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3_prd *cur_prd = usb3_ep->dma->prd;
+       struct usb_request *req = &usb3_req->req;
+       u32 remain, len;
+       int i = 0;
+       int status = 0;
+
+       rmb();  /* The controller updated prd entries */
+
+       do {
+               if (cur_prd->word1 & USB3_PRD1_D)
+                       status = -EIO;
+               if (cur_prd->word1 & USB3_PRD1_E)
+                       len = req->length % USB3_DMA_MAX_XFER_SIZE;
+               else
+                       len = USB3_DMA_MAX_XFER_SIZE;
+               remain = cur_prd->word1 & USB3_PRD1_SIZE_MASK;
+               req->actual += len - remain;
+
+               if (cur_prd->word1 & USB3_PRD1_E ||
+                   (i + 1) < USB3_DMA_NUM_PRD_ENTRIES)
+                       break;
+
+               cur_prd++;
+               i++;
+       } while (1);
+
+       return status;
+}
+
+static bool usb3_dma_try_start(struct renesas_usb3_ep *usb3_ep,
+                              struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+
+       if (!use_dma)
+               return false;
+
+       if (usb3_dma_get_setting_area(usb3_ep, usb3_req)) {
+               usb3_pn_stop(usb3);
+               usb3_enable_dma_pipen(usb3);
+               usb3_dma_fill_prd(usb3_ep, usb3_req);
+               usb3_dma_kick_prd(usb3_ep);
+               usb3_pn_start(usb3);
+               return true;
+       }
+
+       return false;
+}
+
+static int usb3_dma_try_stop(struct renesas_usb3_ep *usb3_ep,
+                            struct renesas_usb3_request *usb3_req)
+{
+       struct renesas_usb3 *usb3 = usb3_ep_to_usb3(usb3_ep);
+       unsigned long flags;
+       int status = 0;
+
+       spin_lock_irqsave(&usb3->lock, flags);
+       if (!usb3_ep->dma)
+               goto out;
+
+       if (!usb3_pn_change(usb3, usb3_ep->num))
+               usb3_disable_dma_pipen(usb3);
+       usb3_dma_stop_prd(usb3_ep);
+       status = usb3_dma_update_status(usb3_ep, usb3_req);
+       usb3_dma_put_setting_area(usb3_ep, usb3_req);
+
+out:
+       spin_unlock_irqrestore(&usb3->lock, flags);
+       return status;
+}
+
+static int renesas_usb3_dma_free_prd(struct renesas_usb3 *usb3,
+                                    struct device *dev)
+{
+       int i;
+       struct renesas_usb3_dma *dma;
+
+       usb3_for_each_dma(usb3, dma, i) {
+               if (dma->prd) {
+                       dma_free_coherent(dev, USB3_DMA_MAX_XFER_SIZE,
+                                         dma->prd, dma->prd_dma);
+                       dma->prd = NULL;
+               }
+       }
+
+       return 0;
+}
+
+static int renesas_usb3_dma_alloc_prd(struct renesas_usb3 *usb3,
+                                     struct device *dev)
+{
+       int i;
+       struct renesas_usb3_dma *dma;
+
+       if (!use_dma)
+               return 0;
+
+       usb3_for_each_dma(usb3, dma, i) {
+               dma->prd = dma_alloc_coherent(dev, USB3_DMA_PRD_SIZE,
+                                             &dma->prd_dma, GFP_KERNEL);
+               if (!dma->prd) {
+                       renesas_usb3_dma_free_prd(usb3, dev);
+                       return -ENOMEM;
+               }
+               dma->num = i + 1;
+       }
+
+       return 0;
+}
+
 static void usb3_start_pipen(struct renesas_usb3_ep *usb3_ep,
                             struct renesas_usb3_request *usb3_req)
 {
@@ -1079,6 +1420,10 @@ static void usb3_start_pipen(struct renesas_usb3_ep *usb3_ep,
                goto out;
 
        usb3_ep->started = true;
+
+       if (usb3_dma_try_start(usb3_ep, usb3_req))
+               goto out;
+
        usb3_pn_start(usb3);
 
        if (usb3_ep->dir_in) {
@@ -1582,12 +1927,49 @@ static void usb3_irq_epc(struct renesas_usb3 *usb3)
        }
 }
 
+static void usb3_irq_dma_int(struct renesas_usb3 *usb3, u32 dma_sta)
+{
+       struct renesas_usb3_ep *usb3_ep;
+       struct renesas_usb3_request *usb3_req;
+       int i, status;
+
+       for (i = 0; i < usb3->num_usb3_eps; i++) {
+               if (!(dma_sta & DMA_INT(i)))
+                       continue;
+
+               usb3_ep = usb3_get_ep(usb3, i);
+               if (!(usb3_read(usb3, USB3_AXI_INT_STA) &
+                   AXI_INT_PRDEN_CLR_STA(usb3_ep->dma->num)))
+                       continue;
+
+               usb3_req = usb3_get_request(usb3_ep);
+               status = usb3_dma_try_stop(usb3_ep, usb3_req);
+               usb3_request_done_pipen(usb3, usb3_ep, usb3_req, status);
+       }
+}
+
+static void usb3_irq_dma(struct renesas_usb3 *usb3)
+{
+       u32 dma_sta = usb3_read(usb3, USB3_DMA_INT_STA);
+
+       dma_sta &= usb3_read(usb3, USB3_DMA_INT_ENA);
+       if (dma_sta) {
+               usb3_write(usb3, dma_sta, USB3_DMA_INT_STA);
+               usb3_irq_dma_int(usb3, dma_sta);
+       }
+}
+
 static irqreturn_t renesas_usb3_irq(int irq, void *_usb3)
 {
        struct renesas_usb3 *usb3 = _usb3;
        irqreturn_t ret = IRQ_NONE;
        u32 axi_int_sta = usb3_read(usb3, USB3_AXI_INT_STA);
 
+       if (axi_int_sta & AXI_INT_DMAINT) {
+               usb3_irq_dma(usb3);
+               ret = IRQ_HANDLED;
+       }
+
        if (axi_int_sta & AXI_INT_EPCINT) {
                usb3_irq_epc(usb3);
                ret = IRQ_HANDLED;
@@ -1686,6 +2068,7 @@ static int renesas_usb3_ep_disable(struct usb_ep *_ep)
                usb3_req = usb3_get_request(usb3_ep);
                if (!usb3_req)
                        break;
+               usb3_dma_try_stop(usb3_ep, usb3_req);
                usb3_request_done(usb3_ep, usb3_req, -ESHUTDOWN);
        } while (1);
 
@@ -1733,6 +2116,7 @@ static int renesas_usb3_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
        dev_dbg(usb3_to_dev(usb3), "ep_dequeue: ep%2d, %u\n", usb3_ep->num,
                _req->length);
 
+       usb3_dma_try_stop(usb3_ep, usb3_req);
        usb3_request_done_pipen(usb3, usb3_ep, usb3_req, -ECONNRESET);
 
        return 0;
@@ -1895,6 +2279,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
        pm_runtime_disable(&pdev->dev);
 
        usb_del_gadget_udc(&usb3->gadget);
+       renesas_usb3_dma_free_prd(usb3, &pdev->dev);
 
        __renesas_usb3_ep_free_request(usb3->ep0_req);
 
@@ -2089,6 +2474,10 @@ static int renesas_usb3_probe(struct platform_device *pdev)
        if (!usb3->ep0_req)
                return -ENOMEM;
 
+       ret = renesas_usb3_dma_alloc_prd(usb3, &pdev->dev);
+       if (ret < 0)
+               goto err_alloc_prd;
+
        ret = usb_add_gadget_udc(&pdev->dev, &usb3->gadget);
        if (ret < 0)
                goto err_add_udc;
@@ -2110,6 +2499,9 @@ err_dev_create:
        usb_del_gadget_udc(&usb3->gadget);
 
 err_add_udc:
+       renesas_usb3_dma_free_prd(usb3, &pdev->dev);
+
+err_alloc_prd:
        __renesas_usb3_ep_free_request(usb3->ep0_req);
 
        return ret;