serial: 8250_dw: Enable DMA support with ACPI
With ACPI 5.0 we can use the FixedDMA Resource Descriptor to extract the needed information for DMA support. Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -27,6 +27,8 @@
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#include <linux/slab.h>
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#include <linux/acpi.h>
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#include "8250.h"
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/* Offsets for the DesignWare specific registers */
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#define DW_UART_USR 0x1f /* UART Status Register */
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#define DW_UART_CPR 0xf4 /* Component Parameter Register */
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@ -143,9 +145,64 @@ static int dw8250_probe_of(struct uart_port *p)
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return 0;
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}
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static bool dw8250_acpi_dma_filter(struct dma_chan *chan, void *parm)
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{
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return chan->chan_id == *(int *)parm;
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}
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static acpi_status
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dw8250_acpi_walk_resource(struct acpi_resource *res, void *data)
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{
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struct uart_port *p = data;
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struct uart_8250_port *port;
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struct uart_8250_dma *dma;
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struct acpi_resource_fixed_dma *fixed_dma;
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struct dma_slave_config *slave;
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port = container_of(p, struct uart_8250_port, port);
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switch (res->type) {
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case ACPI_RESOURCE_TYPE_FIXED_DMA:
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fixed_dma = &res->data.fixed_dma;
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/* TX comes first */
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if (!port->dma) {
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dma = devm_kzalloc(p->dev, sizeof(*dma), GFP_KERNEL);
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if (!dma)
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return AE_NO_MEMORY;
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port->dma = dma;
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slave = &dma->txconf;
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slave->direction = DMA_MEM_TO_DEV;
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slave->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
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slave->slave_id = fixed_dma->request_lines;
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dma->tx_chan_id = fixed_dma->channels;
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dma->tx_param = &dma->tx_chan_id;
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dma->fn = dw8250_acpi_dma_filter;
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} else {
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dma = port->dma;
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slave = &dma->rxconf;
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slave->direction = DMA_DEV_TO_MEM;
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slave->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
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slave->slave_id = fixed_dma->request_lines;
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dma->rx_chan_id = fixed_dma->channels;
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dma->rx_param = &dma->rx_chan_id;
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}
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break;
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}
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return AE_OK;
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}
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static int dw8250_probe_acpi(struct uart_port *p)
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{
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const struct acpi_device_id *id;
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acpi_status status;
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u32 reg;
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id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);
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@ -158,6 +215,14 @@ static int dw8250_probe_acpi(struct uart_port *p)
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p->regshift = 2;
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p->uartclk = (unsigned int)id->driver_data;
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status = acpi_walk_resources(ACPI_HANDLE(p->dev), METHOD_NAME__CRS,
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dw8250_acpi_walk_resource, p);
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if (ACPI_FAILURE(status)) {
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dev_err_ratelimited(p->dev, "%s failed \"%s\"\n", __func__,
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acpi_format_exception(status));
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return -ENODEV;
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}
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/* Fix Haswell issue where the clocks do not get enabled */
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if (!strcmp(id->id, "INT33C4") || !strcmp(id->id, "INT33C5")) {
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reg = readl(p->membase + LPSS_PRV_CLOCK_PARAMS);
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