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spi: spi-ti-qspi: Add DMA support for QSPI mmap read 

Use mem-to-mem DMA to read from flash when reading in mmap mode. This
gives improved read performance and reduces CPU load.

With this patch the raw-read throughput is ~16MB/s on DRA74 EVM. And CPU
load is <20%. UBIFS read throughput ~13 MB/s.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
hifive-unleashed-5.1
Vignesh R 2016-08-17 15:22:37 +05:30 committed by Mark Brown
parent 29b4817d40
commit 5720ec0a6d
1 changed files with 122 additions and 17 deletions
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139
drivers/spi/spi-ti-qspi.c
View File

@ -41,6 +41,8 @@ struct ti_qspi_regs {
};
struct ti_qspi {
struct completion transfer_complete;
/* list synchronization */
struct mutex list_lock;
@ -54,6 +56,9 @@ struct ti_qspi {
struct ti_qspi_regs ctx_reg;
dma_addr_t mmap_phys_base;
struct dma_chan *rx_chan;
u32 spi_max_frequency;
u32 cmd;
u32 dc;
@ -379,6 +384,72 @@ static int qspi_transfer_msg(struct ti_qspi *qspi, struct spi_transfer *t,
return 0;
}
static void ti_qspi_dma_callback(void *param)
{
struct ti_qspi *qspi = param;
complete(&qspi->transfer_complete);
}
static int ti_qspi_dma_xfer(struct ti_qspi *qspi, dma_addr_t dma_dst,
dma_addr_t dma_src, size_t len)
{
struct dma_chan *chan = qspi->rx_chan;
struct dma_device *dma_dev = chan->device;
dma_cookie_t cookie;
enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
struct dma_async_tx_descriptor *tx;
int ret;
tx = dma_dev->device_prep_dma_memcpy(chan, dma_dst, dma_src,
len, flags);
if (!tx) {
dev_err(qspi->dev, "device_prep_dma_memcpy error\n");
return -EIO;
}
tx->callback = ti_qspi_dma_callback;
tx->callback_param = qspi;
cookie = tx->tx_submit(tx);
ret = dma_submit_error(cookie);
if (ret) {
dev_err(qspi->dev, "dma_submit_error %d\n", cookie);
return -EIO;
}
dma_async_issue_pending(chan);
ret = wait_for_completion_timeout(&qspi->transfer_complete,
msecs_to_jiffies(len));
if (ret <= 0) {
dmaengine_terminate_sync(chan);
dev_err(qspi->dev, "DMA wait_for_completion_timeout\n");
return -ETIMEDOUT;
}
return 0;
}
static int ti_qspi_dma_xfer_sg(struct ti_qspi *qspi, struct sg_table rx_sg,
loff_t from)
{
struct scatterlist *sg;
dma_addr_t dma_src = qspi->mmap_phys_base + from;
dma_addr_t dma_dst;
int i, len, ret;
for_each_sg(rx_sg.sgl, sg, rx_sg.nents, i) {
dma_dst = sg_dma_address(sg);
len = sg_dma_len(sg);
ret = ti_qspi_dma_xfer(qspi, dma_dst, dma_src, len);
if (ret)
return ret;
dma_src += len;
}
return 0;
}
static void ti_qspi_enable_memory_map(struct spi_device *spi)
{
struct ti_qspi *qspi = spi_master_get_devdata(spi->master);
@ -426,7 +497,7 @@ static void ti_qspi_setup_mmap_read(struct spi_device *spi,
QSPI_SPI_SETUP_REG(spi->chip_select));
}
static int ti_qspi_spi_flash_read(struct spi_device *spi,
static int ti_qspi_spi_flash_read(struct spi_device *spi,
struct spi_flash_read_message *msg)
{
struct ti_qspi *qspi = spi_master_get_devdata(spi->master);
@ -437,9 +508,23 @@ static int ti_qspi_spi_flash_read(struct spi_device *spi,
if (!qspi->mmap_enabled)
ti_qspi_enable_memory_map(spi);
ti_qspi_setup_mmap_read(spi, msg);
memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
if (qspi->rx_chan) {
if (msg->cur_msg_mapped) {
ret = ti_qspi_dma_xfer_sg(qspi, msg->rx_sg, msg->from);
if (ret)
goto err_unlock;
} else {
dev_err(qspi->dev, "Invalid address for DMA\n");
ret = -EIO;
goto err_unlock;
}
} else {
memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
}
msg->retlen = msg->len;
err_unlock:
mutex_unlock(&qspi->list_lock);
return ret;
@ -536,6 +621,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
struct device_node *np = pdev->dev.of_node;
u32 max_freq;
int ret = 0, num_cs, irq;
dma_cap_mask_t mask;
master = spi_alloc_master(&pdev->dev, sizeof(*qspi));
if (!master)
@ -550,6 +636,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
master->dev.of_node = pdev->dev.of_node;
master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |
SPI_BPW_MASK(8);
master->spi_flash_read = ti_qspi_spi_flash_read;
if (!of_property_read_u32(np, "num-cs", &num_cs))
master->num_chipselect = num_cs;
@ -592,17 +679,6 @@ static int ti_qspi_probe(struct platform_device *pdev)
goto free_master;
}
if (res_mmap) {
qspi->mmap_base = devm_ioremap_resource(&pdev->dev,
res_mmap);
master->spi_flash_read = ti_qspi_spi_flash_read;
if (IS_ERR(qspi->mmap_base)) {
dev_err(&pdev->dev,
"falling back to PIO mode\n");
master->spi_flash_read = NULL;
}
}
qspi->mmap_enabled = false;
if (of_property_read_bool(np, "syscon-chipselects")) {
qspi->ctrl_base =
@ -633,11 +709,37 @@ static int ti_qspi_probe(struct platform_device *pdev)
if (!of_property_read_u32(np, "spi-max-frequency", &max_freq))
qspi->spi_max_frequency = max_freq;
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
goto free_master;
dma_cap_zero(mask);
dma_cap_set(DMA_MEMCPY, mask);
return 0;
qspi->rx_chan = dma_request_chan_by_mask(&mask);
if (!qspi->rx_chan) {
dev_err(qspi->dev,
"No Rx DMA available, trying mmap mode\n");
ret = 0;
goto no_dma;
}
master->dma_rx = qspi->rx_chan;
init_completion(&qspi->transfer_complete);
if (res_mmap)
qspi->mmap_phys_base = (dma_addr_t)res_mmap->start;
no_dma:
if (!qspi->rx_chan && res_mmap) {
qspi->mmap_base = devm_ioremap_resource(&pdev->dev, res_mmap);
if (IS_ERR(qspi->mmap_base)) {
dev_info(&pdev->dev,
"mmap failed with error %ld using PIO mode\n",
PTR_ERR(qspi->mmap_base));
qspi->mmap_base = NULL;
master->spi_flash_read = NULL;
}
}
qspi->mmap_enabled = false;
ret = devm_spi_register_master(&pdev->dev, master);
if (!ret)
return 0;
free_master:
spi_master_put(master);
@ -656,6 +758,9 @@ static int ti_qspi_remove(struct platform_device *pdev)
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
if (qspi->rx_chan)
dma_release_channel(qspi->rx_chan);
return 0;
}