Read in the "snps,ahb-burst" property and set the internal parameter. If
this property is set, it overrides the legacy param value, except for
BCM2835, which can't set this value.
Cc: Stefan Wahren <stefan.wahren@xxxxxxxx>
Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
---
drivers/usb/dwc2/core.h | 9 +++++++
drivers/usb/dwc2/params.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 78 insertions(+)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 9548d3e..75c238c 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -430,6 +430,12 @@ enum dwc2_ep0_state {
* needed.
* 0 - No (default)
* 1 - Yes
+ * @ahb_burst: Specifies the AHB burst.
+ * 0 - Single
+ * 1 - INCR
+ * 3 - INCR4 (default)
+ * 5 - INCR8
+ * 7 - INCR16
* @g_dma: Enables gadget dma usage (default: autodetect).
* @g_dma_desc: Enables gadget descriptor DMA (default: autodetect).
* @g_rx_fifo_size: The periodic rx fifo size for the device, in
@@ -507,6 +513,9 @@ struct dwc2_core_params {
* properties and cannot be set directly in this structure.
*/
+ /* Global parameters */
+ u8 ahb_burst;
+
/* Host parameters */
bool host_dma;
diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index a786256..02ccac7 100644
--- a/drivers/usb/dwc2/params.c
+++ b/drivers/usb/dwc2/params.c
@@ -93,6 +93,13 @@ static const struct dwc2_core_params params_bcm2835 = {
.host_ls_low_power_phy_clk = 0, /* 48 MHz */
.ts_dline = 0,
.reload_ctl = 0,
+
+ /*
+ * Although this value would normally be invalid, for BCM2835,
+ * the GAHBCFG.HBSTLEN field has a different meaning from that
+ * defined by Synopsys. See the BCM2835 databook section 15.2
+ * for details.
+ */
.ahbcfg = 0x10,
.uframe_sched = 0,
.external_id_pin_ctl = -1,
@@ -1091,6 +1098,66 @@ static void dwc2_set_param_tx_fifo_sizes(struct dwc2_hsotg *hsotg)
}
}
+static const char *const ahb_bursts[] = {
+ [GAHBCFG_HBSTLEN_SINGLE] = "SINGLE",
+ [GAHBCFG_HBSTLEN_INCR] = "INCR",
+ [GAHBCFG_HBSTLEN_INCR4] = "INCR4",
+ [GAHBCFG_HBSTLEN_INCR8] = "INCR8",
+ [GAHBCFG_HBSTLEN_INCR16] = "INCR16",
+};
+
+static int dwc2_get_property_ahb_burst(struct dwc2_hsotg *hsotg)
+{
+ struct device_node *node = hsotg->dev->of_node;
+ const char *str = NULL;
+ int burst;
+ int ret;
+
+ ret = device_property_read_string(hsotg->dev,
+ "snps,ahb-burst", &str);
+ if (ret < 0) {
+ return ret;
+ } else if (of_device_is_compatible(node, "brcm,bcm2835-usb")) {
+ dev_warn(hsotg->dev,
+ "snps,ahb-burst is not supported on this platform");
+ return -EINVAL;
+ }
+
+ burst = match_string(ahb_bursts,
+ ARRAY_SIZE(ahb_bursts), str);
+ if (burst < 0) {
+ dev_err(hsotg->dev,
+ "Invalid parameter '%s' for ahb-burst\n", str);
+ }
+
+ return burst;
+}
+
+static void dwc2_set_ahb_burst(struct dwc2_hsotg *hsotg)
+{
+ struct dwc2_core_params *p = &hsotg->params;
+ int burst;
+ int ret;
+
+ /* Default burst value */
+ burst = GAHBCFG_HBSTLEN_INCR4;
+
+ /* Get the legacy param value, if set. */
+ if (p->ahbcfg != -1) {
+ burst = (p->ahbcfg & GAHBCFG_HBSTLEN_MASK) >>
+ GAHBCFG_HBSTLEN_SHIFT;
+ }
+
+ /* Override it from devicetree, if set. */
+ ret = dwc2_get_property_ahb_burst(hsotg);
+ if (ret >= 0)
+ burst = ret;
+
+ /* Set the parameter */
+ p->ahb_burst = (u8)burst;
+ dev_dbg(hsotg->dev, "Setting ahb-burst to %d\n", burst);
+}
+
static void dwc2_set_gadget_dma(struct dwc2_hsotg *hsotg)
{
struct dwc2_hw_params *hw = &hsotg->hw_params;
@@ -1171,6 +1238,8 @@ static void dwc2_set_parameters(struct dwc2_hsotg *hsotg,
dwc2_set_param_external_id_pin_ctl(hsotg, params->external_id_pin_ctl);
dwc2_set_param_hibernation(hsotg, params->hibernation);
+ dwc2_set_ahb_burst(hsotg);
+
/*
* Set devicetree-only parameters. These parameters do not
* take any values from @params.
--
2.10.0
--
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