spi: rockchip-sfc: Fix DMA-API usage

Use DMA-API dma_map_single() call for getting the DMA address of the
transfer buffer instead of hacking with virt_to_phys().

This fixes the following DMA-API debug warning:
------------[ cut here ]------------
DMA-API: rockchip-sfc fe300000.spi: device driver tries to sync DMA memory it has not allocated [device address=0x000000000cf70000] [size=288 bytes]
WARNING: kernel/dma/debug.c:1106 at check_sync+0x1d8/0x690, CPU#2: systemd-udevd/151
Modules linked in: ...
Hardware name: Hardkernel ODROID-M1 (DT)
pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : check_sync+0x1d8/0x690
lr : check_sync+0x1d8/0x690
..
Call trace:
check_sync+0x1d8/0x690 (P)
debug_dma_sync_single_for_cpu+0x84/0x8c
__dma_sync_single_for_cpu+0x88/0x234
rockchip_sfc_exec_mem_op+0x4a0/0x798 [spi_rockchip_sfc]
spi_mem_exec_op+0x408/0x498
spi_nor_read_data+0x170/0x184
spi_nor_read_sfdp+0x74/0xe4
spi_nor_parse_sfdp+0x120/0x11f0
spi_nor_sfdp_init_params_deprecated+0x3c/0x8c
spi_nor_scan+0x690/0xf88
spi_nor_probe+0xe4/0x304
spi_mem_probe+0x6c/0xa8
spi_probe+0x94/0xd4
really_probe+0xbc/0x298
...

Fixes: b69386fcbc60 ("spi: rockchip-sfc: Using normal memory for dma")
Signed-off-by: Marek Szyprowski <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-rockchip-sfc.c

···
 			ret = -ENOMEM;
 			goto err_dma;
 		}
-		sfc->dma_buffer = virt_to_phys(sfc->buffer);
+		sfc->dma_buffer = dma_map_single(dev, sfc->buffer,
+					    sfc->max_iosize, DMA_BIDIRECTIONAL);
+		if (dma_mapping_error(dev, sfc->dma_buffer)) {
+			ret = -ENOMEM;
+			goto err_dma_map;
+		}
 	}
 
 	ret = devm_spi_register_controller(dev, host);
···
 
 	return 0;
 err_register:
+	dma_unmap_single(dev, sfc->dma_buffer, sfc->max_iosize,
+			 DMA_BIDIRECTIONAL);
+err_dma_map:
 	free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
 err_dma:
 	pm_runtime_get_sync(dev);
···
 	struct spi_controller *host = sfc->host;
 
 	spi_unregister_controller(host);
+	dma_unmap_single(&pdev->dev, sfc->dma_buffer, sfc->max_iosize,
+			 DMA_BIDIRECTIONAL);
 	free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
 
 	clk_disable_unprepare(sfc->clk);