Date: Thu, 8 Oct 2020 02:01:29 -0700 From: Mark Millard <marklmi@yahoo.com> To: freebsd-arm <freebsd-arm@freebsd.org> Subject: RPi4B: emmc2bus dma-range handling does not track the boot-time-FDT (u-boot based booting) Message-ID: <D8BDF95A-D6A8-4E95-A0CE-D53068E8355B@yahoo.com> References: <D8BDF95A-D6A8-4E95-A0CE-D53068E8355B.ref@yahoo.com>
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sys/gnu/dts/arm/bcm2711.dtsi reports:
/*
* emmc2 has different DMA constraints based on SoC revisions. =
It was
* moved into its own bus, so as for RPi4's firmware to update =
them.
* The firmware will find whether the emmc2bus alias is defined, =
and if
* so, it'll edit the dma-ranges property below accordingly.
*/
emmc2bus: emmc2bus {
compatible =3D "simple-bus";
#address-cells =3D <2>;
#size-cells =3D <1>;
=20
ranges =3D <0x0 0x7e000000 0x0 0xfe000000 0x01800000>;
dma-ranges =3D <0x0 0xc0000000 0x0 0x00000000 =
0x40000000>;
=20
emmc2: emmc2@7e340000 {
compatible =3D "brcm,bcm2711-emmc2";
reg =3D <0x0 0x7e340000 0x100>;
interrupts =3D <GIC_SPI 126 =
IRQ_TYPE_LEVEL_HIGH>;
clocks =3D <&clocks BCM2711_CLOCK_EMMC2>;
status =3D "disabled";
};
};
The old u-boot/DTB combination in use does not have emmc2bus.
And, even if it did, FreeBSD would not use the dma-ranges
content, expecting it to not vary within the RPi4B family.
Relative to "lowaddr", for example, there is:
#define BCM2838_PERIPH_MAXADDR 0x3fffffff
(the emmc2bus dma-ranges' size_cell_value-1 for the text
above).
sys/arm/broadcom/bcm2835/bcm2835_sdhci.c does list brcm,bcm2711-emmc2 in
its compat_data:
static struct ofw_compat_data compat_data[] =3D {
{"broadcom,bcm2835-sdhci", (uintptr_t)&bcm2835_sdhci_conf},
{"brcm,bcm2835-sdhci", (uintptr_t)&bcm2835_sdhci_conf},
{"brcm,bcm2835-mmc", (uintptr_t)&bcm2835_sdhci_conf},
{"brcm,bcm2711-emmc2", (uintptr_t)&bcm2838_emmc2_conf},
{"brcm,bcm2838-emmc2", (uintptr_t)&bcm2838_emmc2_conf},
{NULL, 0}
};
where BCM2838_PERIPH_MAXADDR is picked out based on:
(from sys/arm/broadcom/bcm2835/bcm2835_vcbus.c)
static struct bcm283x_memory_soc_cfg {
struct bcm283x_memory_mapping *memmap;
const char *soc_compat;
bus_addr_t busdma_lowaddr;
} bcm283x_memory_configs[] =3D {
. . .
{
.memmap =3D bcm2838_memmap,
.soc_compat =3D "brcm,bcm2711",
.busdma_lowaddr =3D BCM2838_PERIPH_MAXADDR,
},
{
.memmap =3D bcm2838_memmap,
.soc_compat =3D "brcm,bcm2838",
.busdma_lowaddr =3D BCM2838_PERIPH_MAXADDR,
},
};
(I've not found tracking of SoC revisions. But I also do
not know what varies across which SoC revisions. So far
as I know, the few I have access to have a uniform
structure.)
=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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