[Pdbg] [PATCH 1/3] enable libpdbg to use i2ctools lib

Alistair Popple alistair at popple.id.au
Wed Apr 10 12:11:18 AEST 2019


Thanks Rashmica, couple of comments below...

> +
> +#define MAX_I2C_BUSES 100
> +static int i2c_buses[100] = {0};

You shouldn't need this as you should be storing the data in the target itself 
(ie. the struct i2cm) rather than creating your own index.

> +static int kernel_i2c_get(struct i2cm *i2cm, uint32_t addr, uint32_t
> offset, uint16_t size, uint64_t *data) +{
> +	int res = 0;
> +	char i2c_path[NAME_MAX];
> +	int i2c_fd;
> +	int bus;
> +
> +	// if no device specified, find first bus that gives us data
> +	//  just read one byte for now
> +	for (bus = 0; bus < MAX_I2C_BUSES; bus++) {

Not sure I follow this - the bus should be specified as part of the struct 
i2cm. What I  would recommend is adding a i2c_fd member to the struct and 
opening it as part of the probe() function.

> +		if (!i2c_buses[bus])
> +			continue;
> +
> +		int len = snprintf(i2c_path, sizeof(i2c_path), "/dev/i2c-%d", bus);
> +		if (len >= NAME_MAX)
> +			continue;
> +
> +		i2c_fd = 0;
> +		i2c_fd = open(i2c_path, O_RDWR);
> +		if (!i2c_fd)
> +			continue;
> +
> +
> +		if (ioctl(i2c_fd, I2C_SLAVE, addr) < 0)

For example this would become:

		if (ioctl(i2cm->i2c_fd, I2C_SLAVE, addr) < 0)

And you wouldn't need the above checks or loop.

> +			continue;
> +
> +		res = i2c_smbus_read_byte_data(i2c_fd, offset);
> +		if (res >= 0) {
> +			PR_DEBUG("read %x from device %x on bus %s\n", res, addr, 
i2c_path);
> +			*data = (uint64_t)res;
> +			return res;
> +		}
> +	}
> +	return -1;
> +}
> +
> +static int i2cbus_probe(struct pdbg_target *target)
> +{
> +    FILE *f = NULL;
> +	int len;
> +	char n[NAME_MAX];
> +
> +	if (!target->index)
> +		return -1;
> +
> +	len = snprintf(n, NAME_MAX, "/dev/i2c-%i", target->index);
> +	if (len >= NAME_MAX)
> +		return -1;
> +	f = fopen(n, "r");
> +	if (f == NULL)
> +		return -1;
> +	i2c_buses[target->index] = 1;

Therefore you would end up with the code from the kernel_i2c_get() loop here 
instead:

		int len = snprintf(i2c_path, sizeof(i2c_path), "/dev/i2c-%d", bus);
		if (len >= NAME_MAX)
			continue;

		i2c_fd = open(i2c_path, O_RDWR);
		if (!i2c_fd)
			return -1;

		i2cm->i2c_fs = i2c_fd;

> +	return 0;
> +}
> +
> +static struct i2cm i2c_bus = {
> +	.target = {
> +		.name =	"I2C Bus",
> +		.compatible = "ibm,power9-i2c-port",
> +		.class = "i2cm",
> +		.probe = i2cbus_probe,
> +	},
> +	.read = kernel_i2c_get,
> +};
> +DECLARE_HW_UNIT(i2c_bus);
> +#endif
> diff --git a/libpdbg/libpdbg.h b/libpdbg/libpdbg.h
> index 4fad158..c9e6569 100644
> --- a/libpdbg/libpdbg.h
> +++ b/libpdbg/libpdbg.h
> @@ -123,6 +123,9 @@ struct pdbg_target *pdbg_address_absolute(struct
> pdbg_target *target, uint64_t * int fsi_read(struct pdbg_target *target,
> uint32_t addr, uint32_t *val); int fsi_write(struct pdbg_target *target,
> uint32_t addr, uint32_t val);
> 
> +int i2c_read(struct pdbg_target *target, uint16_t port, uint32_t addr,
> +		uint32_t offset, uint16_t size, uint64_t *data);
> +
>  int pib_read(struct pdbg_target *target, uint64_t addr, uint64_t *val);
>  int pib_write(struct pdbg_target *target, uint64_t addr, uint64_t val);
>  int pib_wait(struct pdbg_target *pib_dt, uint64_t addr, uint64_t mask,
> uint64_t data); diff --git a/libpdbg/target.c b/libpdbg/target.c
> index e678470..1bf252e 100644
> --- a/libpdbg/target.c
> +++ b/libpdbg/target.c
> @@ -195,6 +195,17 @@ int opb_write(struct pdbg_target *opb_dt, uint32_t
> addr, uint32_t data) return opb->write(opb, addr64, data);
>  }
> 
> +int i2c_read(struct pdbg_target *i2cm_dt, uint16_t port, uint32_t addr,
> uint32_t offset, uint16_t size, uint64_t *data) +{
> +	struct i2cm *i2cm;
> +	uint64_t addr64 = addr;
> +
> +	i2cm_dt = get_class_target_addr(i2cm_dt, "i2cm", &addr64);
> +	i2cm = target_to_i2cm(i2cm_dt);
> +
> +	return i2cm->read(i2cm, port, addr, offset, size, data);
> +}
> +
>  int fsi_read(struct pdbg_target *fsi_dt, uint32_t addr, uint32_t *data)
>  {
>  	struct fsi *fsi;
> diff --git a/libpdbg/target.h b/libpdbg/target.h
> index 04897ed..eb22377 100644
> --- a/libpdbg/target.h
> +++ b/libpdbg/target.h
> @@ -138,6 +138,15 @@ struct fsi {
>  };
>  #define target_to_fsi(x) container_of(x, struct fsi, target)
> 
> +struct i2cm {
> +	struct pdbg_target target;
> +	int (*read)(struct i2cm *, uint16_t, uint32_t, uint32_t, uint16_t,
> uint64_t *); +	int (*write)(struct i2cm *, uint16_t, uint32_t, uint32_t,
> uint16_t, uint64_t); +	bool host;
> +};
> +#define target_to_i2cm(x) container_of(x, struct i2cm, target)
> +
> +
>  struct core {
>  	struct pdbg_target target;
>  	bool release_spwkup;
> diff --git a/p9-i2c.dts.m4 b/p9-i2c.dts.m4
> new file mode 100644
> index 0000000..8e8270f
> --- /dev/null
> +++ b/p9-i2c.dts.m4
> @@ -0,0 +1,21 @@
> +define(`I2CBUS', `i2c-bus@$1 {
> +bus-frequency = <0x61a80>;
> +compatible = "ibm,opal-i2c", "ibm,power8-i2c-port", "ibm,power9-i2c-port";
> +index = <$1>;
> +reg = <0x0 0x0 $1>;
> +}')dnl
> +
> +I2CBUS(0);
> +I2CBUS(1);
> +I2CBUS(2);
> +I2CBUS(3);
> +I2CBUS(4);
> +I2CBUS(5);
> +I2CBUS(6);
> +I2CBUS(7);
> +I2CBUS(8);
> +I2CBUS(9);
> +I2CBUS(10);
> +I2CBUS(11);
> +I2CBUS(12);
> +I2CBUS(13);
> diff --git a/p9-kernel.dts.m4 b/p9-kernel.dts.m4
> index 195be59..474beca 100644
> --- a/p9-kernel.dts.m4
> +++ b/p9-kernel.dts.m4
> @@ -22,6 +22,14 @@
>  			include(p9-pib.dts.m4)dnl
>  		};
> 
> +		i2cm at 1800 {
> +			#address-cells = <0x2>;
> +			#size-cells = <0x1>;
> +			reg = <0x0 0x1800 0x400>;
> +			compatible = "ibm,kernel-i2c-master";
> +			include(p9-i2c.dts.m4)dnl
> +		};
> +
>  		hmfsi at 100000 {
>  			#address-cells = <0x2>;
>  			#size-cells = <0x1>;
> diff --git a/src/i2c.c b/src/i2c.c
> new file mode 100644
> index 0000000..2a32ec2
> --- /dev/null
> +++ b/src/i2c.c
> @@ -0,0 +1,44 @@
> +/* Copyright 2019 IBM Corp.
> + *
> + * Licensed under the Apache License, Version 2.0 (the "License");
> + * you may not use this file except in compliance with the License.
> + * You may obtain a copy of the License at
> + *
> + * 	http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
> + * implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +
> +#include <libpdbg.h>
> +#include <inttypes.h>
> +
> +#include "main.h"
> +#include "optcmd.h"
> +#include "path.h"
> +#include "target.h"
> +
> +static int geti2c(uint16_t port, uint32_t addr, uint32_t offset, uint16_t
> size) +{
> +	uint64_t data = 0xc0ffee;
> +	struct pdbg_target *target, *selected = NULL;
> +
> +	for_each_path_target_class("i2cbus", target) {
> +		if (pdbg_target_probe(target) != PDBG_TARGET_ENABLED)
> +			continue;
> +		selected = target;
> +		if (i2c_read(target, port, addr, offset, size, &data) == 0)
> +			break;
> +		break;
> +	}
> +
> +	if (selected == NULL)
> +		return -1;
> +	printf("data read: 0x%016" PRIx64 "\n",  data);
> +	return 0;
> +}
> +OPTCMD_DEFINE_CMD_WITH_ARGS(geti2c, geti2c, (DATA16, ADDRESS32, ADDRESS32,
> DATA16)); diff --git a/src/main.c b/src/main.c
> index d5f9385..1702efa 100644
> --- a/src/main.c
> +++ b/src/main.c
> @@ -93,7 +93,7 @@ extern struct optcmd_cmd
>  	optcmd_threadstatus, optcmd_sreset, optcmd_regs, optcmd_probe,
>  	optcmd_getmem, optcmd_putmem, optcmd_getmemio, optcmd_putmemio,
>  	optcmd_getxer, optcmd_putxer, optcmd_getcr, optcmd_putcr,
> -	optcmd_gdbserver;
> +	optcmd_gdbserver, optcmd_geti2c;
> 
>  static struct optcmd_cmd *cmds[] = {
>  	&optcmd_getscom, &optcmd_putscom, &optcmd_getcfam, &optcmd_putcfam,
> @@ -103,7 +103,7 @@ static struct optcmd_cmd *cmds[] = {
>  	&optcmd_threadstatus, &optcmd_sreset, &optcmd_regs, &optcmd_probe,
>  	&optcmd_getmem, &optcmd_putmem, &optcmd_getmemio, &optcmd_putmemio,
>  	&optcmd_getxer, &optcmd_putxer, &optcmd_getcr, &optcmd_putcr,
> -	&optcmd_gdbserver,
> +	&optcmd_gdbserver, &optcmd_geti2c,
>  };
> 
>  /* Purely for printing usage text. We could integrate printing argument and
> flag @@ -145,6 +145,7 @@ static struct action actions[] = {
>  	{ "sreset",  "", "Reset" },
>  	{ "regs",  "[--backtrace]", "State (optionally display backtrace)" },
>  	{ "gdbserver", "", "Start a gdb server" },
> +	{ "geti2c", "<port> <device> <offset> <size>", "Read size bytes from the
> offset of specified device" }, };
> 
>  static void print_usage(void)




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