On 10/12/2017 07:41 AM, Julien Thierry wrote: > Hi Jim, > > On 11/10/17 23:34, Jim Quinlan wrote: >> From: Florian Fainelli <f.fainelli@xxxxxxxxx> >> >> This commit adds a memory API suitable for ascertaining the sizes of >> each of the N memory controllers in a Broadcom STB chip. Its first >> user will be the Broadcom STB PCIe root complex driver, which needs >> to know these sizes to properly set up DMA mappings for inbound >> regions. >> >> We cannot use memblock here or anything like what Linux provides >> because it collapses adjacent regions within a larger block, and here >> we actually need per-memory controller addresses and sizes, which is >> why we resort to manual DT parsing. >> >> Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx> >> --- >> drivers/soc/bcm/brcmstb/Makefile | 2 +- >> drivers/soc/bcm/brcmstb/memory.c | 183 >> +++++++++++++++++++++++++++++++++++++++ >> include/soc/brcmstb/memory_api.h | 25 ++++++ >> 3 files changed, 209 insertions(+), 1 deletion(-) >> create mode 100644 drivers/soc/bcm/brcmstb/memory.c >> create mode 100644 include/soc/brcmstb/memory_api.h >> >> diff --git a/drivers/soc/bcm/brcmstb/Makefile >> b/drivers/soc/bcm/brcmstb/Makefile >> index 9120b27..4cea7b6 100644 >> --- a/drivers/soc/bcm/brcmstb/Makefile >> +++ b/drivers/soc/bcm/brcmstb/Makefile >> @@ -1 +1 @@ >> -obj-y += common.o biuctrl.o >> +obj-y += common.o biuctrl.o memory.o >> diff --git a/drivers/soc/bcm/brcmstb/memory.c >> b/drivers/soc/bcm/brcmstb/memory.c >> new file mode 100644 >> index 0000000..cb6bf73 >> --- /dev/null >> +++ b/drivers/soc/bcm/brcmstb/memory.c >> @@ -0,0 +1,183 @@ >> +/* >> + * Copyright © 2015-2017 Broadcom >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + * >> + * A copy of the GPL is available at >> + * http://www.broadcom.com/licenses/GPLv2.php or from the Free Software >> + * Foundation at https://www.gnu.org/licenses/ . >> + */ >> + >> +#include <linux/device.h> >> +#include <linux/io.h> >> +#include <linux/libfdt.h> >> +#include <linux/of_address.h> >> +#include <linux/of_fdt.h> >> +#include <linux/sizes.h> >> +#include <soc/brcmstb/memory_api.h> >> + >> +/* -------------------- Constants -------------------- */ >> + >> +/* Macros to help extract property data */ >> +#define U8TOU32(b, offs) \ >> + ((((u32)b[0 + offs] << 0) & 0x000000ff) | \ >> + (((u32)b[1 + offs] << 8) & 0x0000ff00) | \ >> + (((u32)b[2 + offs] << 16) & 0x00ff0000) | \ >> + (((u32)b[3 + offs] << 24) & 0xff000000)) >> + >> +#define DT_PROP_DATA_TO_U32(b, offs) (fdt32_to_cpu(U8TOU32(b, offs))) >> + > > I fail to understand why this is not: > > #define DT_PROP_DATA_TO_U32(b, offs) (fdt32_to_cpu(*(u32*)(b + offs))) > > > If I understand correctly, fdt data is in big endian, the macro U8TOU32 > reads it as little endian. My guess is that this won't work on big > endian kernels but should work on little endian since fdt32_to_cpu will > revert the bytes again. > > Am I missing something? No, your point is valid, there is no reason why this cannot be fdt32_to_cpu() here. -- Florian
