You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
171 lines
5.4 KiB
Diff
171 lines
5.4 KiB
Diff
From f505fc71c85f0f87e45d4890ae9e7762c38e6c9a Mon Sep 17 00:00:00 2001
|
|
From: Phil Elwell <phil@raspberrypi.org>
|
|
Date: Tue, 8 Mar 2016 09:49:16 +0000
|
|
Subject: [PATCH] bcm2835-mmc: Only claim one DMA channel
|
|
|
|
With both MMC controllers enabled there are few DMA channels left. The
|
|
bcm2835-mmc 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-mmc.c | 69 +++++++++++++++++++++++++----------
|
|
2 files changed, 51 insertions(+), 23 deletions(-)
|
|
|
|
--- a/arch/arm/boot/dts/bcm2708_common.dtsi
|
|
+++ b/arch/arm/boot/dts/bcm2708_common.dtsi
|
|
@@ -232,9 +232,8 @@
|
|
reg = <0x7e300000 0x100>;
|
|
interrupts = <2 30>;
|
|
clocks = <&clk_mmc>;
|
|
- dmas = <&dma 11>,
|
|
- <&dma 11>;
|
|
- dma-names = "tx", "rx";
|
|
+ dmas = <&dma 11>;
|
|
+ dma-names = "rx-tx";
|
|
brcm,overclock-50 = <0>;
|
|
status = "disabled";
|
|
};
|
|
--- a/drivers/mmc/host/bcm2835-mmc.c
|
|
+++ b/drivers/mmc/host/bcm2835-mmc.c
|
|
@@ -108,8 +108,9 @@ struct bcm2835_host {
|
|
u32 shadow;
|
|
|
|
/*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_rxtx; /* DMA channel for reads and writes */
|
|
+ struct dma_slave_config dma_cfg_rx;
|
|
+ struct dma_slave_config dma_cfg_tx;
|
|
struct dma_async_tx_descriptor *tx_desc; /* descriptor */
|
|
|
|
bool have_dma;
|
|
@@ -342,7 +343,7 @@ static void bcm2835_mmc_dma_complete(voi
|
|
|
|
if (host->data && !(host->data->flags & MMC_DATA_WRITE)) {
|
|
/* otherwise handled in SDHCI IRQ */
|
|
- dma_chan = host->dma_chan_rx;
|
|
+ dma_chan = host->dma_chan_rxtx;
|
|
dir_data = DMA_FROM_DEVICE;
|
|
|
|
dma_unmap_sg(dma_chan->device->dev,
|
|
@@ -493,16 +494,21 @@ static void bcm2835_mmc_transfer_dma(str
|
|
if (host->blocks == 0)
|
|
return;
|
|
|
|
+ dma_chan = host->dma_chan_rxtx;
|
|
if (host->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;
|
|
}
|
|
|
|
+ /* 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);
|
|
+
|
|
BUG_ON(!dma_chan->device);
|
|
BUG_ON(!dma_chan->device->dev);
|
|
BUG_ON(!host->data->sg);
|
|
@@ -936,7 +942,7 @@ static void bcm2835_mmc_data_irq(struct
|
|
if (host->data->flags & MMC_DATA_WRITE) {
|
|
/* IRQ handled here */
|
|
|
|
- dma_chan = host->dma_chan_tx;
|
|
+ dma_chan = host->dma_chan_rxtx;
|
|
dir_data = DMA_TO_DEVICE;
|
|
dma_unmap_sg(dma_chan->device->dev,
|
|
host->data->sg, host->data->sg_len,
|
|
@@ -1316,28 +1322,47 @@ static int bcm2835_mmc_add_host(struct b
|
|
dev_info(dev, "Forcing PIO mode\n");
|
|
host->have_dma = false;
|
|
#else
|
|
- if (IS_ERR_OR_NULL(host->dma_chan_tx) ||
|
|
- IS_ERR_OR_NULL(host->dma_chan_rx)) {
|
|
- dev_err(dev, "%s: Unable to initialise DMA channels. Falling back to PIO\n",
|
|
+ if (IS_ERR_OR_NULL(host->dma_chan_rxtx)) {
|
|
+ dev_err(dev, "%s: Unable to initialise DMA channel. Falling back to PIO\n",
|
|
DRIVER_NAME);
|
|
host->have_dma = false;
|
|
} else {
|
|
- dev_info(dev, "DMA channels allocated");
|
|
- host->have_dma = true;
|
|
+ dev_info(dev, "DMA channel allocated");
|
|
|
|
cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
|
|
cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
|
|
cfg.slave_id = 11; /* DREQ channel */
|
|
|
|
+ /* Validate the slave configurations */
|
|
+
|
|
cfg.direction = DMA_MEM_TO_DEV;
|
|
cfg.src_addr = 0;
|
|
cfg.dst_addr = host->bus_addr + SDHCI_BUFFER;
|
|
- ret = dmaengine_slave_config(host->dma_chan_tx, &cfg);
|
|
|
|
- cfg.direction = DMA_DEV_TO_MEM;
|
|
- cfg.src_addr = host->bus_addr + SDHCI_BUFFER;
|
|
- 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 + SDHCI_BUFFER;
|
|
+ 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. "
|
|
+ "Faling back to PIO\n",
|
|
+ mmc_hostname(mmc));
|
|
+ dma_release_channel(host->dma_chan_rxtx);
|
|
+ host->dma_chan_rxtx = NULL;
|
|
+ host->use_dma = false;
|
|
+ }
|
|
}
|
|
#endif
|
|
mmc->max_segs = 128;
|
|
@@ -1416,16 +1441,20 @@ static int bcm2835_mmc_probe(struct plat
|
|
|
|
#ifndef FORCE_PIO
|
|
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 = dma_request_channel(mask, NULL, NULL);
|
|
+ host->dma_chan_rxtx = dma_request_channel(mask, NULL, NULL);
|
|
}
|
|
#endif
|
|
clk = devm_clk_get(dev, NULL);
|