[PATCH] bcma: get SoC device struct & assign dma_mask

[Florian Fainelli <f.fainelli@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

For bus devices to be fully usable it's required to set their DMA
parameters.

For years it has been missing and remained unnoticed because of
mips_dma_alloc_coherent() silently handling the empty coherent_dma_mask.
Kernel 4.19 came with a lot of DMA changes and caused a regression on
the bcm47xx. Starting with the commit f8c55dc6e828 ("MIPS: use generic
dma noncoherent ops for simple noncoherent platforms") DMA coherent
allocations just fail. Example:
[    1.114914] bgmac_bcma bcma0:2: Allocation of TX ring 0x200 failed
[    1.121215] bgmac_bcma bcma0:2: Unable to alloc memory for DMA
[    1.127626] bgmac_bcma: probe of bcma0:2 failed with error -12
[    1.133838] bgmac_bcma: Broadcom 47xx GBit MAC driver loaded

This change fixes above regression in addition to the MIPS bcm47xx
commit 321c46b91550 ("MIPS: BCM47XX: Setup struct device for the SoC").

It also fixes another *old* GPIO regression caused by a parent pointing
to the NULL:
[    0.157054] missing gpiochip .dev parent pointer
[    0.157287] bcma: bus0: Error registering GPIO driver: -22
introduced by the commit 74f4e0cc6108 ("bcma: switch GPIO portions to
use GPIOLIB_IRQCHIP").

Fixes: f8c55dc6e828 ("MIPS: use generic dma noncoherent ops for simple noncoherent platforms")
Fixes: 74f4e0cc6108 ("bcma: switch GPIO portions to use GPIOLIB_IRQCHIP")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
---
Christoph,

I don't know if this is what you had in mind. I am also not sure if we
should have the bcma_bus_type implement .dma_configure and set it to
platform_dma_configure?

 drivers/bcma/host_soc.c | 2 ++
 drivers/bcma/main.c     | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/bcma/host_soc.c b/drivers/bcma/host_soc.c
index 90d5bdc12e03..fd2e8ff17c76 100644
--- a/drivers/bcma/host_soc.c
+++ b/drivers/bcma/host_soc.c
@@ -191,6 +191,8 @@ int __init bcma_host_soc_init(struct bcma_soc *soc)
 	struct bcma_bus *bus = &soc->bus;
 	int err;
 
+	bus->dev = soc->dev;
+
 	/* Scan bus and initialize it */
 	err = bcma_bus_early_register(bus);
 	if (err)
diff --git a/drivers/bcma/main.c b/drivers/bcma/main.c
index 8e7ca3e4c8c4..6793c2ff60fd 100644
--- a/drivers/bcma/main.c
+++ b/drivers/bcma/main.c
@@ -253,6 +253,8 @@ void bcma_prepare_core(struct bcma_bus *bus, struct bcma_device *core)
 		if (IS_ENABLED(CONFIG_OF) && bus->dev) {
 			core->dma_dev = bus->dev;
 		} else {
+			if (!core->dev.coherent_dma_mask)
+				core->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 			core->dev.dma_mask = &core->dev.coherent_dma_mask;
 			core->dma_dev = &core->dev;
 		}
-- 
2.25.1