You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
160 lines
5.0 KiB
160 lines
5.0 KiB
From 71804345eb4c8408fb50b0f15b750915776a20ad Mon Sep 17 00:00:00 2001
|
|
From: Phil Elwell <phil@raspberrypi.org>
|
|
Date: Mon, 7 Mar 2016 16:46:39 +0000
|
|
Subject: [PATCH 167/423] bcm2835-sdhost: Only claim one DMA channel
|
|
|
|
With both MMC controllers enabled there are few DMA channels left. The
|
|
bcm2835-sdhost driver only uses DMA in one direction at a time, so it
|
|
doesn't need to claim two channels.
|
|
|
|
See: https://github.com/raspberrypi/linux/issues/1327
|
|
|
|
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
|
|
---
|
|
arch/arm/boot/dts/bcm2708_common.dtsi | 5 +--
|
|
drivers/mmc/host/bcm2835-sdhost.c | 70 ++++++++++++++++++++++++-----------
|
|
2 files changed, 50 insertions(+), 25 deletions(-)
|
|
|
|
--- a/arch/arm/boot/dts/bcm2708_common.dtsi
|
|
+++ b/arch/arm/boot/dts/bcm2708_common.dtsi
|
|
@@ -136,9 +136,8 @@
|
|
reg = <0x7e202000 0x100>;
|
|
interrupts = <2 24>;
|
|
clocks = <&clk_core>;
|
|
- dmas = <&dma 13>,
|
|
- <&dma 13>;
|
|
- dma-names = "tx", "rx";
|
|
+ dmas = <&dma 13>;
|
|
+ dma-names = "rx-tx";
|
|
brcm,overclock-50 = <0>;
|
|
brcm,pio-limit = <1>;
|
|
status = "disabled";
|
|
--- a/drivers/mmc/host/bcm2835-sdhost.c
|
|
+++ b/drivers/mmc/host/bcm2835-sdhost.c
|
|
@@ -185,9 +185,10 @@ struct bcm2835_host {
|
|
unsigned int debug:1; /* Enable debug output */
|
|
|
|
/*DMA part*/
|
|
- struct dma_chan *dma_chan_rx; /* DMA channel for reads */
|
|
- struct dma_chan *dma_chan_tx; /* DMA channel for writes */
|
|
- struct dma_chan *dma_chan; /* Channel in used */
|
|
+ struct dma_chan *dma_chan_rxtx; /* DMA channel for reads and writes */
|
|
+ struct dma_chan *dma_chan; /* Channel in use */
|
|
+ struct dma_slave_config dma_cfg_rx;
|
|
+ struct dma_slave_config dma_cfg_tx;
|
|
struct dma_async_tx_descriptor *dma_desc;
|
|
u32 dma_dir;
|
|
u32 drain_words;
|
|
@@ -771,12 +772,11 @@ static void bcm2835_sdhost_prepare_dma(s
|
|
log_event("PRD<", (u32)data, 0);
|
|
pr_debug("bcm2835_sdhost_prepare_dma()\n");
|
|
|
|
+ dma_chan = host->dma_chan_rxtx;
|
|
if (data->flags & MMC_DATA_READ) {
|
|
- dma_chan = host->dma_chan_rx;
|
|
dir_data = DMA_FROM_DEVICE;
|
|
dir_slave = DMA_DEV_TO_MEM;
|
|
} else {
|
|
- dma_chan = host->dma_chan_tx;
|
|
dir_data = DMA_TO_DEVICE;
|
|
dir_slave = DMA_MEM_TO_DEV;
|
|
}
|
|
@@ -813,6 +813,12 @@ static void bcm2835_sdhost_prepare_dma(s
|
|
host->drain_words = len/4;
|
|
}
|
|
|
|
+ /* The parameters have already been validated, so this will not fail */
|
|
+ (void)dmaengine_slave_config(dma_chan,
|
|
+ (dir_data == DMA_FROM_DEVICE) ?
|
|
+ &host->dma_cfg_rx :
|
|
+ &host->dma_cfg_tx);
|
|
+
|
|
len = dma_map_sg(dma_chan->device->dev, data->sg, data->sg_len,
|
|
dir_data);
|
|
|
|
@@ -1805,28 +1811,46 @@ int bcm2835_sdhost_add_host(struct bcm28
|
|
spin_lock_init(&host->lock);
|
|
|
|
if (host->allow_dma) {
|
|
- if (IS_ERR_OR_NULL(host->dma_chan_tx) ||
|
|
- IS_ERR_OR_NULL(host->dma_chan_rx)) {
|
|
- pr_err("%s: unable to initialise DMA channels. "
|
|
+ if (IS_ERR_OR_NULL(host->dma_chan_rxtx)) {
|
|
+ pr_err("%s: unable to initialise DMA channel. "
|
|
"Falling back to PIO\n",
|
|
mmc_hostname(mmc));
|
|
host->use_dma = false;
|
|
} else {
|
|
- host->use_dma = true;
|
|
-
|
|
cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
|
|
cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
|
|
cfg.slave_id = 13; /* DREQ channel */
|
|
|
|
+ /* Validate the slave configurations */
|
|
+
|
|
cfg.direction = DMA_MEM_TO_DEV;
|
|
cfg.src_addr = 0;
|
|
cfg.dst_addr = host->bus_addr + SDDATA;
|
|
- ret = dmaengine_slave_config(host->dma_chan_tx, &cfg);
|
|
|
|
- cfg.direction = DMA_DEV_TO_MEM;
|
|
- cfg.src_addr = host->bus_addr + SDDATA;
|
|
- cfg.dst_addr = 0;
|
|
- ret = dmaengine_slave_config(host->dma_chan_rx, &cfg);
|
|
+ ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);
|
|
+
|
|
+ if (ret == 0) {
|
|
+ host->dma_cfg_tx = cfg;
|
|
+
|
|
+ cfg.direction = DMA_DEV_TO_MEM;
|
|
+ cfg.src_addr = host->bus_addr + SDDATA;
|
|
+ cfg.dst_addr = 0;
|
|
+
|
|
+ ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);
|
|
+ }
|
|
+
|
|
+ if (ret == 0) {
|
|
+ host->dma_cfg_rx = cfg;
|
|
+
|
|
+ host->use_dma = true;
|
|
+ } else {
|
|
+ pr_err("%s: unable to configure DMA channel. "
|
|
+ "Falling back to PIO\n",
|
|
+ mmc_hostname(mmc));
|
|
+ dma_release_channel(host->dma_chan_rxtx);
|
|
+ host->dma_chan_rxtx = NULL;
|
|
+ host->use_dma = false;
|
|
+ }
|
|
}
|
|
} else {
|
|
host->use_dma = false;
|
|
@@ -1948,19 +1972,21 @@ static int bcm2835_sdhost_probe(struct p
|
|
|
|
if (host->allow_dma) {
|
|
if (node) {
|
|
- host->dma_chan_tx =
|
|
- dma_request_slave_channel(dev, "tx");
|
|
- host->dma_chan_rx =
|
|
- dma_request_slave_channel(dev, "rx");
|
|
+ host->dma_chan_rxtx =
|
|
+ dma_request_slave_channel(dev, "rx-tx");
|
|
+ if (!host->dma_chan_rxtx)
|
|
+ host->dma_chan_rxtx =
|
|
+ dma_request_slave_channel(dev, "tx");
|
|
+ if (!host->dma_chan_rxtx)
|
|
+ host->dma_chan_rxtx =
|
|
+ dma_request_slave_channel(dev, "rx");
|
|
} else {
|
|
dma_cap_mask_t mask;
|
|
|
|
dma_cap_zero(mask);
|
|
/* we don't care about the channel, any would work */
|
|
dma_cap_set(DMA_SLAVE, mask);
|
|
- host->dma_chan_tx =
|
|
- dma_request_channel(mask, NULL, NULL);
|
|
- host->dma_chan_rx =
|
|
+ host->dma_chan_rxtx =
|
|
dma_request_channel(mask, NULL, NULL);
|
|
}
|
|
}
|
|
|