diff --git a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
index c33e9a32d496ef1091338747a92700e6c0c259d0..2bfc6e7ed0947304e45d8ca0b2dadcea3cb838ee 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
@@ -19,6 +19,11 @@ Required properties:
Optional properties:
- clock-frequency : frequency of bus clock in Hz. Default 100kHz if unset.
+- dmas : Must contain a list of two references to DMA
+ specifiers, one for transmission, and one for
+ reception.
+- dma-names : Must contain a list of two DMA names, "tx" and "rx".
+
Pinctrl properties might be needed, too. See there.
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index de609be677939c67437a208ac6cbebedb5f12c1d..d9a5622b89c8424cbb1fdbc4be39829f1bfa4ce0 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -1,6 +1,8 @@
/*
* SuperH Mobile I2C Controller
*
+ * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
+ *
* Copyright (C) 2008 Magnus Damm
*
* Portions of the code based on out-of-tree driver i2c-sh7343.c
@@ -18,6 +20,8 @@
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c/i2c-sh_mobile.h>
@@ -110,6 +114,7 @@ enum sh_mobile_i2c_op {
OP_TX_FIRST,
OP_TX,
OP_TX_STOP,
+ OP_TX_STOP_DATA,
OP_TX_TO_RX,
OP_RX,
OP_RX_STOP,
@@ -134,6 +139,11 @@ struct sh_mobile_i2c_data {
int pos;
int sr;
bool send_stop;
+
+ struct dma_chan *dma_tx;
+ struct dma_chan *dma_rx;
+ struct scatterlist sg;
+ enum dma_data_direction dma_direction;
};
struct sh_mobile_dt_config {
@@ -171,6 +181,8 @@ struct sh_mobile_dt_config {
#define ICIC_ICCLB8 0x80
#define ICIC_ICCHB8 0x40
+#define ICIC_TDMAE 0x20
+#define ICIC_RDMAE 0x10
#define ICIC_ALE 0x08
#define ICIC_TACKE 0x04
#define ICIC_WAITE 0x02
@@ -332,8 +344,10 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
case OP_TX: /* write data */
iic_wr(pd, ICDR, data);
break;
- case OP_TX_STOP: /* write data and issue a stop afterwards */
+ case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
iic_wr(pd, ICDR, data);
+ /* fallthrough */
+ case OP_TX_STOP: /* issue a stop */
iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
: ICCR_ICE | ICCR_TRS | ICCR_BBSY);
break;
@@ -389,13 +403,17 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
{
unsigned char data;
- if (pd->pos == pd->msg->len)
+ if (pd->pos == pd->msg->len) {
+ /* Send stop if we haven't yet (DMA case) */
+ if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY))
+ i2c_op(pd, OP_TX_STOP, 0);
return 1;
+ }
sh_mobile_i2c_get_data(pd, &data);
if (sh_mobile_i2c_is_last_byte(pd))
- i2c_op(pd, OP_TX_STOP, data);
+ i2c_op(pd, OP_TX_STOP_DATA, data);
else if (sh_mobile_i2c_is_first_byte(pd))
i2c_op(pd, OP_TX_FIRST, data);
else
@@ -450,7 +468,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
struct platform_device *dev = dev_id;
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
unsigned char sr;
- int wakeup;
+ int wakeup = 0;
sr = iic_rd(pd, ICSR);
pd->sr |= sr; /* remember state */
@@ -459,15 +477,21 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
(pd->msg->flags & I2C_M_RD) ? "read" : "write",
pd->pos, pd->msg->len);
- if (sr & (ICSR_AL | ICSR_TACK)) {
+ /* Kick off TxDMA after preface was done */
+ if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
+ iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
+ else if (sr & (ICSR_AL | ICSR_TACK))
/* don't interrupt transaction - continue to issue stop */
iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
- wakeup = 0;
- } else if (pd->msg->flags & I2C_M_RD)
+ else if (pd->msg->flags & I2C_M_RD)
wakeup = sh_mobile_i2c_isr_rx(pd);
else
wakeup = sh_mobile_i2c_isr_tx(pd);
+ /* Kick off RxDMA after preface was done */
+ if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
+ iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
+
if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
@@ -482,6 +506,79 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
+{
+ if (pd->dma_direction == DMA_NONE)
+ return;
+ else if (pd->dma_direction == DMA_FROM_DEVICE)
+ dmaengine_terminate_all(pd->dma_rx);
+ else if (pd->dma_direction == DMA_TO_DEVICE)
+ dmaengine_terminate_all(pd->dma_tx);
+
+ dma_unmap_single(pd->dev, sg_dma_address(&pd->sg),
+ pd->msg->len, pd->dma_direction);
+
+ pd->dma_direction = DMA_NONE;
+}
+
+static void sh_mobile_i2c_dma_callback(void *data)
+{
+ struct sh_mobile_i2c_data *pd = data;
+
+ dma_unmap_single(pd->dev, sg_dma_address(&pd->sg),
+ pd->msg->len, pd->dma_direction);
+
+ pd->dma_direction = DMA_NONE;
+ pd->pos = pd->msg->len;
+
+ iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
+}
+
+static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
+{
+ bool read = pd->msg->flags & I2C_M_RD;
+ enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+ struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
+ struct dma_async_tx_descriptor *txdesc;
+ dma_addr_t dma_addr;
+ dma_cookie_t cookie;
+
+ if (!chan)
+ return;
+
+ dma_addr = dma_map_single(pd->dev, pd->msg->buf, pd->msg->len, dir);
+ if (dma_mapping_error(pd->dev, dma_addr)) {
+ dev_dbg(pd->dev, "dma map failed, using PIO\n");
+ return;
+ }
+
+ sg_dma_len(&pd->sg) = pd->msg->len;
+ sg_dma_address(&pd->sg) = dma_addr;
+
+ pd->dma_direction = dir;
+
+ txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
+ read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!txdesc) {
+ dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
+ sh_mobile_i2c_cleanup_dma(pd);
+ return;
+ }
+
+ txdesc->callback = sh_mobile_i2c_dma_callback;
+ txdesc->callback_param = pd;
+
+ cookie = dmaengine_submit(txdesc);
+ if (dma_submit_error(cookie)) {
+ dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
+ sh_mobile_i2c_cleanup_dma(pd);
+ return;
+ }
+
+ dma_async_issue_pending(chan);
+}
+
static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
bool do_init)
{
@@ -506,6 +603,9 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
pd->pos = -1;
pd->sr = 0;
+ if (pd->msg->len > 8)
+ sh_mobile_i2c_xfer_dma(pd);
+
/* Enable all interrupts to begin with */
iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
return 0;
@@ -589,6 +689,9 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
5 * HZ);
if (!k) {
dev_err(pd->dev, "Transfer request timed out\n");
+ if (pd->dma_direction != DMA_NONE)
+ sh_mobile_i2c_cleanup_dma(pd);
+
err = -ETIMEDOUT;
break;
}
@@ -639,6 +742,62 @@ static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
+static int sh_mobile_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir,
+ dma_addr_t port_addr, struct dma_chan **chan_ptr)
+{
+ dma_cap_mask_t mask;
+ struct dma_chan *chan;
+ struct dma_slave_config cfg;
+ char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
+ int ret;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ *chan_ptr = NULL;
+
+ chan = dma_request_slave_channel_reason(dev, chan_name);
+ if (IS_ERR(chan)) {
+ ret = PTR_ERR(chan);
+ dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
+ return ret;
+ }
+
+ memset(&cfg, 0, sizeof(cfg));
+ cfg.direction = dir;
+ if (dir == DMA_MEM_TO_DEV) {
+ cfg.dst_addr = port_addr;
+ cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ } else {
+ cfg.src_addr = port_addr;
+ cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ }
+
+ ret = dmaengine_slave_config(chan, &cfg);
+ if (ret) {
+ dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
+ dma_release_channel(chan);
+ return ret;
+ }
+
+ *chan_ptr = chan;
+
+ dev_dbg(dev, "got DMA channel for %s\n", chan_name);
+ return 0;
+}
+
+static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
+{
+ if (pd->dma_tx) {
+ dma_release_channel(pd->dma_tx);
+ pd->dma_tx = NULL;
+ }
+
+ if (pd->dma_rx) {
+ dma_release_channel(pd->dma_rx);
+ pd->dma_rx = NULL;
+ }
+}
+
static int sh_mobile_i2c_hook_irqs(struct platform_device *dev)
{
struct resource *res;
@@ -725,6 +884,21 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
if (ret)
return ret;
+ /* Init DMA */
+ sg_init_table(&pd->sg, 1);
+ pd->dma_direction = DMA_NONE;
+ ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
+ res->start + ICDR, &pd->dma_rx);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+
+ ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
+ res->start + ICDR, &pd->dma_tx);
+ if (ret == -EPROBE_DEFER) {
+ sh_mobile_i2c_release_dma(pd);
+ return ret;
+ }
+
/* Enable Runtime PM for this device.
*
* Also tell the Runtime PM core to ignore children
@@ -756,6 +930,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
+ sh_mobile_i2c_release_dma(pd);
dev_err(&dev->dev, "cannot add numbered adapter\n");
return ret;
}
@@ -772,6 +947,7 @@ static int sh_mobile_i2c_remove(struct platform_device *dev)
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
+ sh_mobile_i2c_release_dma(pd);
pm_runtime_disable(&dev->dev);
return 0;
}
@@ -808,16 +984,15 @@ static int __init sh_mobile_i2c_adap_init(void)
{
return platform_driver_register(&sh_mobile_i2c_driver);
}
+subsys_initcall(sh_mobile_i2c_adap_init);
static void __exit sh_mobile_i2c_adap_exit(void)
{
platform_driver_unregister(&sh_mobile_i2c_driver);
}
-
-subsys_initcall(sh_mobile_i2c_adap_init);
module_exit(sh_mobile_i2c_adap_exit);
MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
-MODULE_AUTHOR("Magnus Damm");
+MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-sh_mobile");