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From: Gadiyar, Anand <gadiyar@ti.com>
Date: Wed, 13 Aug 2008 07:05:29 +0000 (+0530)
Subject: MUSB: Workaround for simultaneous TX and RX usage
X-Git-Url: http://git.mansr.com/?p=linux-omap;a=commitdiff_plain;h=2e6aa4efb0e14c51ff0427927b1b38136911fa93
MUSB: Workaround for simultaneous TX and RX usage
MUSB: Workaround for simultaneous TX and RX usage
MUSB RTL V1.4 has a hardware issue which results in a DMA controller
hang when TX and RX DMA channels are simultaneously enabled. This
affects at least OMAP2430 and OMAP34XX.
Since RX transfers are in Mode 0 and anyway result in one DMA interrupt
per packet, we can use System DMA to unload the RX fifos. MUSB DMA can
be used for all TX channels as before.
Tested with full-duplex TX and RX transfers using g_ether. Runs for 24
hours without a hang. Without this patch, the hang occurs within minutes.
This issue was first reported by Jon Hunter on [1]
[1] http://marc.info/?l=linux-omap&m=119634480534453&w=2
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
---
diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index a485a86..8583e54 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -150,6 +150,14 @@ config USB_INVENTRA_DMA
help
Enable DMA transfers using Mentor's engine.
+config MUSB_USE_SYSTEM_DMA_RX
+ bool 'Use System DMA for RX endpoints'
+ depends on USB_MUSB_HDRC && USB_INVENTRA_DMA
+ help
+ MUSB RTL version 1.4 has a hardware issue when TX and RX DMA
+ channels are simultaneously enabled. To work around this issue,
+ you can choose to use System DMA for RX channels.
+
config USB_TI_CPPI_DMA
bool
depends on USB_MUSB_HDRC && !MUSB_PIO_ONLY
diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index 32bb1e2..d1c1ea0 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -34,6 +34,7 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include "musb_core.h"
+#include <asm/dma.h>
#if defined(CONFIG_ARCH_OMAP2430) || defined(CONFIG_ARCH_OMAP3430)
#include "omap2430.h"
@@ -64,6 +65,9 @@
#define MUSB_HSDMA_CHANNELS 8
+#define MUSB_FIFO_ADDRESS(epnum) \
+ ((unsigned long) (OMAP_HSOTG_BASE + MUSB_FIFO_OFFSET(epnum)))
+
struct musb_dma_controller;
struct musb_dma_channel {
@@ -75,6 +79,8 @@ struct musb_dma_channel {
u8 bIndex;
u8 epnum;
u8 transmit;
+
+ int sysdma_channel;
};
struct musb_dma_controller {
@@ -93,6 +99,42 @@ static int dma_controller_start(struct dma_controller *c)
return 0;
}
+#ifdef CONFIG_MUSB_USE_SYSTEM_DMA_RX
+static void musb_sysdma_completion(int lch, u16 ch_status, void *data)
+{
+ u32 dwAddress;
+ unsigned long flags;
+
+ struct dma_channel *pChannel;
+
+ struct musb_dma_channel *pImplChannel =
+ (struct musb_dma_channel *) data;
+ struct musb_dma_controller *controller = pImplChannel->controller;
+ struct musb *musb = controller->pDmaPrivate;
+ pChannel = &pImplChannel->Channel;
+
+ DBG(2, "lch = 0x%d, ch_status = 0x%x\n", lch, ch_status);
+ spin_lock_irqsave(&musb->lock, flags);
+
+ dwAddress = (u32) omap_get_dma_dst_pos(pImplChannel->sysdma_channel);
+ pChannel->actual_len = dwAddress - pImplChannel->dwStartAddress;
+
+ DBG(2, "ch %p, 0x%x -> 0x%x (%d / %d) %s\n",
+ pChannel, pImplChannel->dwStartAddress, dwAddress,
+ pChannel->actual_len, pImplChannel->len,
+ (pChannel->actual_len < pImplChannel->len) ?
+ "=> reconfig 0": "=> complete");
+
+ pChannel->status = MUSB_DMA_STATUS_FREE;
+ musb_dma_completion(musb, pImplChannel->epnum, pImplChannel->transmit);
+
+ spin_unlock_irqrestore(&musb->lock, flags);
+ return;
+}
+#else
+#define musb_sysdma_completion NULL
+#endif
+
static void dma_channel_release(struct dma_channel *pChannel);
static int dma_controller_stop(struct dma_controller *c)
@@ -144,6 +186,29 @@ static struct dma_channel *dma_channel_allocate(struct dma_controller *c,
/* Tx => mode 1; Rx => mode 0 */
pChannel->desired_mode = transmit;
pChannel->actual_len = 0;
+ pImplChannel->sysdma_channel = -1;
+
+#ifdef CONFIG_MUSB_USE_SYSTEM_DMA_RX
+ if (!transmit) {
+ int ret;
+ ret = omap_request_dma(OMAP24XX_DMA_NO_DEVICE,
+ "MUSB SysDMA", musb_sysdma_completion,
+ (void *) pImplChannel,
+ &(pImplChannel->sysdma_channel));
+
+ if (ret) {
+ printk(KERN_ERR "request_dma failed:"
+ " %d\n", ret);
+ controller->bmUsedChannels &=
+ ~(1 << bBit);
+ pChannel->status =
+ MUSB_DMA_STATUS_UNKNOWN;
+ pImplChannel->sysdma_channel = -1;
+ pChannel = NULL;
+ }
+ }
+#endif
+
break;
}
}
@@ -163,6 +228,12 @@ static void dma_channel_release(struct dma_channel *pChannel)
~(1 << pImplChannel->bIndex);
pChannel->status = MUSB_DMA_STATUS_UNKNOWN;
+
+ if (pImplChannel->sysdma_channel != -1) {
+ omap_stop_dma(pImplChannel->sysdma_channel);
+ omap_free_dma(pImplChannel->sysdma_channel);
+ pImplChannel->sysdma_channel = -1;
+ }
}
static void configure_channel(struct dma_channel *pChannel,
@@ -179,41 +250,69 @@ static void configure_channel(struct dma_channel *pChannel,
DBG(4, "%p, pkt_sz %d, addr 0x%x, len %d, mode %d\n",
pChannel, packet_sz, dma_addr, len, mode);
- if (mode) {
- csr |= 1 << MUSB_HSDMA_MODE1_SHIFT;
- BUG_ON(len < packet_sz);
+ if (pImplChannel->sysdma_channel != -1) {
+ /* System DMA */
+ /* RX: set src = FIFO */
+
+ omap_set_dma_transfer_params(pImplChannel->sysdma_channel,
+ OMAP_DMA_DATA_TYPE_S8,
+ len, 1, /* One frame */
+ OMAP_DMA_SYNC_ELEMENT,
+ OMAP24XX_DMA_NO_DEVICE,
+ 0); /* Src Sync */
+
+ omap_set_dma_src_params(pImplChannel->sysdma_channel, 0,
+ OMAP_DMA_AMODE_CONSTANT,
+ MUSB_FIFO_ADDRESS(pImplChannel->epnum),
+ 0, 0);
- if (packet_sz >= 64) {
- csr |= MUSB_HSDMA_BURSTMODE_INCR16
+ omap_set_dma_dest_params(pImplChannel->sysdma_channel, 0,
+ OMAP_DMA_AMODE_POST_INC, dma_addr,
+ 0, 0);
+
+ omap_set_dma_dest_data_pack(pImplChannel->sysdma_channel, 1);
+ omap_set_dma_dest_burst_mode(pImplChannel->sysdma_channel,
+ OMAP_DMA_DATA_BURST_16);
+
+ omap_start_dma(pImplChannel->sysdma_channel);
+
+ } else { /* Mentor DMA */
+ if (mode) {
+ csr |= 1 << MUSB_HSDMA_MODE1_SHIFT;
+ BUG_ON(len < packet_sz);
+
+ if (packet_sz >= 64) {
+ csr |= MUSB_HSDMA_BURSTMODE_INCR16
<< MUSB_HSDMA_BURSTMODE_SHIFT;
- } else if (packet_sz >= 32) {
- csr |= MUSB_HSDMA_BURSTMODE_INCR8
+ } else if (packet_sz >= 32) {
+ csr |= MUSB_HSDMA_BURSTMODE_INCR8
<< MUSB_HSDMA_BURSTMODE_SHIFT;
- } else if (packet_sz >= 16) {
- csr |= MUSB_HSDMA_BURSTMODE_INCR4
+ } else if (packet_sz >= 16) {
+ csr |= MUSB_HSDMA_BURSTMODE_INCR4
<< MUSB_HSDMA_BURSTMODE_SHIFT;
+ }
}
- }
- csr |= (pImplChannel->epnum << MUSB_HSDMA_ENDPOINT_SHIFT)
- | (1 << MUSB_HSDMA_ENABLE_SHIFT)
- | (1 << MUSB_HSDMA_IRQENABLE_SHIFT)
- | (pImplChannel->transmit
- ? (1 << MUSB_HSDMA_TRANSMIT_SHIFT)
- : 0);
-
- /* address/count */
- musb_writel(mbase,
- MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_ADDRESS),
- dma_addr);
- musb_writel(mbase,
- MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_COUNT),
- len);
-
- /* control (this should start things) */
- musb_writew(mbase,
- MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_CONTROL),
- csr);
+ csr |= (pImplChannel->epnum << MUSB_HSDMA_ENDPOINT_SHIFT)
+ | (1 << MUSB_HSDMA_ENABLE_SHIFT)
+ | (1 << MUSB_HSDMA_IRQENABLE_SHIFT)
+ | (pImplChannel->transmit
+ ? (1 << MUSB_HSDMA_TRANSMIT_SHIFT)
+ : 0);
+
+ /* address/count */
+ musb_writel(mbase,
+ MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_ADDRESS),
+ dma_addr);
+ musb_writel(mbase,
+ MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_COUNT),
+ len);
+
+ /* control (this should start things) */
+ musb_writew(mbase,
+ MUSB_HSDMA_CHANNEL_OFFSET(bChannel, MUSB_HSDMA_CONTROL),
+ csr);
+ } /* Mentor DMA */
}
static int dma_channel_program(struct dma_channel *pChannel,
@@ -265,6 +364,12 @@ static int dma_channel_abort(struct dma_channel *pChannel)
MUSB_EP_OFFSET(pImplChannel->epnum, MUSB_TXCSR),
csr);
} else {
+ if (pImplChannel->sysdma_channel != -1) {
+ omap_stop_dma(pImplChannel->sysdma_channel);
+ omap_free_dma(pImplChannel->sysdma_channel);
+ pImplChannel->sysdma_channel = -1;
+ }
+
csr = musb_readw(mbase,
MUSB_EP_OFFSET(pImplChannel->epnum, MUSB_RXCSR));
csr &= ~(MUSB_RXCSR_AUTOCLEAR |
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