Re: [kvm-ppc-devel] [PATCH 5 of 7] Add dynamic device

[Hollis Blanchard <hollisb@us.ibm.com>]

You've misspelled "licence" several times in this patch.

On Tue, 2008-03-11 at 23:50 -0500, Jerone Young wrote:
> # HG changeset patch
> # User Jerone Young <jyoung5@us.ibm.com>
> # Date 1205296680 18000
> # Branch merge
> # Node ID 50fddb23a4c19ec6f359a4dd39e98712eb6bcaeb
> # Parent  9c15709640cd55bf6f782d6856423363312493bb
> Add dynamic device tree manipulation & change uboot loader for PPC
> bamboo board model
> 
> This patch adds code to dynamically manipulate the device tree when
> loaded into memory. This allows us to finally have the ability to
> manipulate the kernel command line & initrd from the qemu command
> line. This will also let us setup different settings for the board.
> 
> This patch also now uses new uboot loader uboot_loader_l() to load
> kernel image.

So the load_uboot() part should be a separate patch, right?

> Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
> 
> diff --git a/qemu/Makefile.target b/qemu/Makefile.target
> --- a/qemu/Makefile.target
> +++ b/qemu/Makefile.target
> @@ -615,7 +615,7 @@ OBJS+= unin_pci.o ppc_chrp.o
>  OBJS+= unin_pci.o ppc_chrp.o
>  # PowerPC 4xx boards
>  OBJS+= pflash_cfi02.o ppc4xx_devs.o ppc405_uc.o ppc405_boards.o
> -OBJS+= ppc440.o ppc440_bamboo.o
> +OBJS+= ppc440.o ppc440_bamboo.o ppc_device_tree_support.o
>  endif
>  ifeq ($(TARGET_BASE_ARCH), mips)
>  OBJS+= mips_r4k.o mips_malta.o mips_pica61.o mips_mipssim.o
> diff --git a/qemu/hw/ppc440_bamboo.c b/qemu/hw/ppc440_bamboo.c
> --- a/qemu/hw/ppc440_bamboo.c
> +++ b/qemu/hw/ppc440_bamboo.c
> @@ -8,11 +8,12 @@
>   *
>   */
> 
> +#include "config.h"
>  #include "ppc440.h"
> +#include "qemu-kvm.h"
> +#include "ppc_device_tree_support.h"
> 
> -#define KERNEL_LOAD_ADDR 0x400000 /* uboot loader puts kernel at 4MB */
> -
> -#include "qemu-kvm.h"
> +#define BINARY_DEVICE_TREE_FILE "bamboo.dtb"
> 
>  /* PPC 440 refrence demo board
>   *
> @@ -26,14 +27,22 @@ void bamboo_init(ram_addr_t ram_size, in
>  			const char *initrd_filename,
>  			const char *cpu_model)
>  {
> +	char buf[1024];	
>  	target_phys_addr_t ram_bases[2], ram_sizes[2];
>  	qemu_irq *pic;
>  	CPUState *env;
> -	target_ulong ep;
> +	target_ulong ep=0;
> +	target_ulong la=0;
>  	int is_linux=1; /* Will assume allways is Linux for now */
> -	long kernel_size=0;
> +	target_long kernel_size=0;
>  	target_ulong initrd_base=0;
> -	target_ulong initrd_size=0;
> +	target_long initrd_size=0;
> +	target_ulong dt_base=0;
> +	void *fdt;
> +	int ret;
> +
> +	uint32_t cpu_freq;
> +	uint32_t timebase_freq;
> 
>  	printf("%s: START\n", __func__);
> 
> @@ -78,18 +87,23 @@ void bamboo_init(ram_addr_t ram_size, in
> 
>  	/* load kernel with uboot loader */
>  	printf("%s: load kernel\n", __func__);
> -	kernel_size = load_uboot(kernel_filename, &ep, &is_linux);
> +	load_uboot_l(kernel_filename, &ep, &la, &kernel_size, &is_linux);
>  	if (kernel_size < 0) {
>  		fprintf(stderr, "qemu: could not load kernel '%s'\n",
>  			kernel_filename);
>  		exit(1);
>  	}
> +	printf("kernel is at guest address: 0x%lx\n", (unsigned long)la);
> 
>  	/* load initrd */
>  	if (initrd_filename) {
> -		initrd_base = kernel_size + KERNEL_LOAD_ADDR;
> +        	initrd_base = kernel_size + la;
> +		printf("%s: load initrd\n", __func__);
>  		initrd_size = load_image(initrd_filename,
>  				phys_ram_base + initrd_base);
> +
> +		printf("initrd is at guest address: 0x%lx\n", 
> +					(unsigned long) initrd_base);
> 
>  		if (initrd_size < 0) {
>  			fprintf(stderr,
> @@ -99,17 +113,58 @@ void bamboo_init(ram_addr_t ram_size, in
>  		}
>  	}
> 
> +#ifdef CONFIG_LIBFDT
> +	/* get variable for device tree */
> +	cpu_freq = get_proc_dt_prop_cpu_clock_freq();
> +	timebase_freq = get_proc_dt_prop_cpu_timebase_freq();
> +
> +	/* load binary device tree into qemu (not guest memory) */
> +	printf("%s: load device tree file\n", __func__);
> +	
> +	snprintf(buf, sizeof(buf), "%s/%s", bios_dir, 
> +		BINARY_DEVICE_TREE_FILE);
> +
> +	/* set base for device tree that will be in guest memory */	
> +	if (initrd_base)
> +		dt_base = initrd_base + initrd_size;
> +	else
> +		dt_base = kernel_size + la;
> +
> +	fdt = load_device_tree(buf, (phys_ram_base + dt_base));
> +	if (fdt = NULL) {
> +		printf("Loading device tree failed!\n");
> +		exit(1);
> +	}
> +
> +	printf("device tree address is at guest address: 0x%lx\n", 
> +		(unsigned long) dt_base);
> +
> +	/* manipulate device tree in memory */
> +	set_dt_cpu_0_clock_freq_prop(fdt, cpu_freq);
> +	set_dt_cpu_0_timebase_prop(fdt, timebase_freq);
> +
> +	set_dt_initrd_start_prop(fdt, initrd_base);
> +	set_dt_initrd_end_prop(fdt, (initrd_base + initrd_size));
> +
> +	set_dt_bootargs_prop(fdt, kernel_cmdline);
> +#endif
> +
>  	if (kvm_enabled()) {
> -	    /* XXX insert TLB entries */
> -	    env->gpr[1] = (16<<20) - 8;
> -	    env->gpr[4] = initrd_base;
> -	    env->gpr[5] = initrd_size;
> 
> -	    env->nip = ep;
> +		/* XXX insert TLB entries */
> +		env->gpr[1] = (16<<20) - 8;

Please fix your whitespace.

> -	    env->cpu_index = 0;
> -	    printf("%s: loading kvm registers\n", __func__);
> -	    kvm_load_registers(env);
> +#ifdef CONFIG_LIBFDT
> +		/* location of device tree in register */
> +		env->gpr[3] = dt_base;
> +#else
> +		env->gpr[4] = initrd_base;
> +		env->gpr[5] = initrd_size;
> +#endif

Linux ignores R4 and R5 regardless of whether qemu has libfdt support or
not. Those should be removed.

> +		env->nip = ep;
> +
> +		printf("%s: loading kvm registers\n", __func__);
> +		kvm_load_registers(env);
>  	}
> 
>  	printf("%s: DONE\n", __func__);
> diff --git a/qemu/hw/ppc_device_tree_support.c b/qemu/hw/ppc_device_tree_support.c
> new file mode 100644
> --- /dev/null
> +++ b/qemu/hw/ppc_device_tree_support.c

This is a really long file name.

> @@ -0,0 +1,223 @@
> +/*
> + * Functions to help device tree manipulation using libfdt.
> + * It also provides functions to read entries from device tree proc
> + * interface.
> + *
> + * Copyright 2008 IBM Corporation.
> + * Authors: Jerone Young <jyoung5@us.ibm.com>
> + *
> + * This work is licensed under the GNU GPL licence version 2 or later.
> + *
> + */
> +
> +#include <stdio.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +
> +#include "config.h"
> +#include "ppc440.h"
> +
> +#ifdef CONFIG_LIBFDT
> +	#include "libfdt.h"
> +#endif

Don't indent this.

> +#define DT_PROC_INTERFACE_PATH "/proc/device-tree"
> +
> +/* FUNCTIONS FOR READING FROM DEVICE TREE OF HOST IN /PROC */
> +
> +/* This function reads device-tree property files that are of
> + * a single cell size
> + */
> +static uint32_t read_proc_device_tree_prop_cell(char *path_in_device_tree)
> +{
> +	char buf[1024];
> +	uint32_t num;
> +	FILE *stream;
> +
> +	snprintf(buf, sizeof(buf), "%s/%s",  DT_PROC_INTERFACE_PATH,
> +		path_in_device_tree);
> +
> +	stream = fopen(buf, "rb");
> +	
> +	if (stream = NULL)
> +	{
> +		printf("%s: Unable to open '%s'\n", __func__, buf);
> +		exit(1);
> +	}
> +
> +	fread(&num, sizeof(num), 1, stream);
> +	fclose(stream);
> +
> +	return num;
> +} 

I hate that "buf" variable. You can use snprintf() with length 0 to find
out how much memory to malloc.

...
> +void set_dt_cpu_0_timebase_prop(void *fdt, uint32_t timebase)
> +{	
> +	int offset;
> +	offset = get_offset_of_node(fdt, "/cpus/cpu@0");
> +	set_dt_prop_cell(fdt, offset, "timebase-frequency",
> +			timebase);
> +
> +}
> +
> +void set_dt_initrd_start_prop(void *fdt, uint32_t start_addr)
> +{
> +	int offset;
> +	offset = get_offset_of_node(fdt, "/chosen");
> +	set_dt_prop_cell(fdt, offset, "linux,initrd-start",
> +			start_addr);
> +}
> +
> +void set_dt_initrd_end_prop(void *fdt, uint32_t end_addr)
> +{
> +	int offset;
> +	offset = get_offset_of_node(fdt, "/chosen");
> +	set_dt_prop_cell(fdt, offset, "linux,initrd-end",
> +			end_addr);
> +}
> +
> +void set_dt_bootargs_prop(void *fdt, char *cmdline)
> +{
> +	int offset;
> +	offset = get_offset_of_node(fdt, "/chosen");
> +	set_dt_prop_string(fdt,offset, "bootargs", cmdline);
> +}
> +
> +#endif

These are also really long function names. If you're basically going to
encode the full device tree path into the function name, I don't think
they're very convenient and they're not worth having. You could just
pass the path in from the caller.

-- 
Hollis Blanchard
IBM Linux Technology Center


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