Re: [RFC PATCH 01/10] CHROMIUM: cros_ec: Remove cros_ec dependency in lpc_mec

From: Enric Balletbo Serra
Date: Mon Dec 17 2018 - 10:50:29 EST

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Hi Nick,

Many thanks for sending this upstream. Adding Guenter as also might be
interested and some minor comments below.

Missatge de Nick Crews <ncrews@xxxxxxxxxx> del dia ds., 15 de des.
2018 a les 1:21:
>
> From: Duncan Laurie <dlaurie@xxxxxxxxxx>
>
> In order to allow this code to be re-used, remove the dependency
> on the rest of the cros_ec code from the cros_ec_lpc_mec functions.
>
> Instead of using a hardcoded register base address of 0x800 have
> this be passed in to cros_ec_lpc_mec_init(). The existing cros_ec
> use case now passes in the 0x800 base address this way.
>
> Signed-off-by: Duncan Laurie <dlaurie@xxxxxxxxxx>
> Signed-off-by: Nick Crews <ncrews@xxxxxxxxxx>
> ---

For this patch and the rest of this series remove the CHROMIUM tag
from the subject. Use the format 'platform/chrome: cros_ec: ...'

>
> drivers/platform/chrome/cros_ec_lpc_mec.c | 54 +++++++++++++++++++----
> drivers/platform/chrome/cros_ec_lpc_mec.h | 45 +++++++++++--------
> drivers/platform/chrome/cros_ec_lpc_reg.c | 43 +++++-------------
> 3 files changed, 85 insertions(+), 57 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.c b/drivers/platform/chrome/cros_ec_lpc_mec.c
> index c4edfa83e493..18bd9f82be6c 100644
> --- a/drivers/platform/chrome/cros_ec_lpc_mec.c
> +++ b/drivers/platform/chrome/cros_ec_lpc_mec.c
> @@ -24,6 +24,7 @@
> #include <linux/delay.h>
> #include <linux/io.h>
> #include <linux/mfd/cros_ec_commands.h>
> +#include <linux/mfd/cros_ec_lpc_mec.h>

This file does not exist, you'll get a build error with only this
patch applied. I think the file is already included.

> #include <linux/mutex.h>
> #include <linux/types.h>
>
> @@ -34,6 +35,7 @@
> * EC mutex because memmap data may be accessed without it being held.
> */
> static struct mutex io_mutex;
> +static u16 mec_emi_base, mec_emi_end;
>
> /*
> * cros_ec_lpc_mec_emi_write_address
> @@ -46,10 +48,39 @@ static struct mutex io_mutex;
> static void cros_ec_lpc_mec_emi_write_address(u16 addr,
> enum cros_ec_lpc_mec_emi_access_mode access_type)
> {
> - /* Address relative to start of EMI range */
> - addr -= MEC_EMI_RANGE_START;
> - outb((addr & 0xfc) | access_type, MEC_EMI_EC_ADDRESS_B0);
> - outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1);
> + outb((addr & 0xfc) | access_type, MEC_EMI_EC_ADDRESS_B0(mec_emi_base));
> + outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1(mec_emi_base));
> +}
> +
> +/*
> + * cros_ec_lpc_mec_in_range
> + *

For this and all other functions that you are documenting below use
the standard kernel-doc format, please. See:
https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html

> + * Determine if requested addresses are in MEC EMI range.
> + *
> + * @offset: Address offset
> + * @length: Number of bytes to check
> + *
> + * @return 1 if in range, 0 if not, and -1 if there is an error
> + * such as the mec range not being initialized
> + */

Can't you use 0 if it's ok and -errno if it fails here? Will you
handle 0 and -1 errors in a different way?

> +int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length)
> +{
> + if (length == 0)
> + return -1;
> +
> + if (WARN_ON(mec_emi_base == 0 || mec_emi_end == 0))
> + return -1;
> +
> + if (offset >= mec_emi_base && offset < mec_emi_end) {
> + if (WARN_ON(offset + length - 1 <= mec_emi_end))
> + return -1;
> + return 1;
> + }
> +
> + if (WARN_ON(offset + length > mec_emi_base && offset < mec_emi_end))
> + return -1;
> +
> + return 0;
> }
>
> /*
> @@ -71,6 +102,11 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
> u8 sum = 0;
> enum cros_ec_lpc_mec_emi_access_mode access, new_access;
>
> + /* Return checksum of 0 if window is not initialized */
> + WARN_ON(mec_emi_base == 0 || mec_emi_end == 0);
> + if (mec_emi_base == 0 || mec_emi_end == 0)
> + return 0;
> +
> /*
> * Long access cannot be used on misaligned data since reading B0 loads
> * the data register and writing B3 flushes.
> @@ -86,9 +122,9 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
> cros_ec_lpc_mec_emi_write_address(offset, access);
>
> /* Skip bytes in case of misaligned offset */
> - io_addr = MEC_EMI_EC_DATA_B0 + (offset & 0x3);
> + io_addr = MEC_EMI_EC_DATA_B0(mec_emi_base) + (offset & 0x3);
> while (i < length) {
> - while (io_addr <= MEC_EMI_EC_DATA_B3) {
> + while (io_addr <= MEC_EMI_EC_DATA_B3(mec_emi_base)) {
> if (io_type == MEC_IO_READ)
> buf[i] = inb(io_addr++);
> else
> @@ -118,7 +154,7 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
> }
>
> /* Access [B0, B3] on each loop pass */
> - io_addr = MEC_EMI_EC_DATA_B0;
> + io_addr = MEC_EMI_EC_DATA_B0(mec_emi_base);
> }
>
> done:
> @@ -128,9 +164,11 @@ u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
> }
> EXPORT_SYMBOL(cros_ec_lpc_io_bytes_mec);
>
> -void cros_ec_lpc_mec_init(void)
> +void cros_ec_lpc_mec_init(unsigned int base, unsigned int end)
> {
> mutex_init(&io_mutex);
> + mec_emi_base = base;
> + mec_emi_end = end;
> }
> EXPORT_SYMBOL(cros_ec_lpc_mec_init);
>
> diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.h b/drivers/platform/chrome/cros_ec_lpc_mec.h
> index 105068c0e919..a81cc6a8b621 100644
> --- a/drivers/platform/chrome/cros_ec_lpc_mec.h
> +++ b/drivers/platform/chrome/cros_ec_lpc_mec.h
> @@ -24,8 +24,6 @@
> #ifndef __CROS_EC_LPC_MEC_H
> #define __CROS_EC_LPC_MEC_H
>
> -#include <linux/mfd/cros_ec_commands.h>
> -
> enum cros_ec_lpc_mec_emi_access_mode {
> /* 8-bit access */
> ACCESS_TYPE_BYTE = 0x0,
> @@ -45,35 +43,46 @@ enum cros_ec_lpc_mec_io_type {
> MEC_IO_WRITE,
> };
>
> -/* Access IO ranges 0x800 thru 0x9ff using EMI interface instead of LPC */
> -#define MEC_EMI_RANGE_START EC_HOST_CMD_REGION0
> -#define MEC_EMI_RANGE_END (EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE)
> -
> /* EMI registers are relative to base */
> -#define MEC_EMI_BASE 0x800
> -#define MEC_EMI_HOST_TO_EC (MEC_EMI_BASE + 0)
> -#define MEC_EMI_EC_TO_HOST (MEC_EMI_BASE + 1)
> -#define MEC_EMI_EC_ADDRESS_B0 (MEC_EMI_BASE + 2)
> -#define MEC_EMI_EC_ADDRESS_B1 (MEC_EMI_BASE + 3)
> -#define MEC_EMI_EC_DATA_B0 (MEC_EMI_BASE + 4)
> -#define MEC_EMI_EC_DATA_B1 (MEC_EMI_BASE + 5)
> -#define MEC_EMI_EC_DATA_B2 (MEC_EMI_BASE + 6)
> -#define MEC_EMI_EC_DATA_B3 (MEC_EMI_BASE + 7)
> +#define MEC_EMI_HOST_TO_EC(MEC_EMI_BASE) (MEC_EMI_BASE + 0)
> +#define MEC_EMI_EC_TO_HOST(MEC_EMI_BASE) (MEC_EMI_BASE + 1)
> +#define MEC_EMI_EC_ADDRESS_B0(MEC_EMI_BASE) (MEC_EMI_BASE + 2)
> +#define MEC_EMI_EC_ADDRESS_B1(MEC_EMI_BASE) (MEC_EMI_BASE + 3)
> +#define MEC_EMI_EC_DATA_B0(MEC_EMI_BASE) (MEC_EMI_BASE + 4)
> +#define MEC_EMI_EC_DATA_B1(MEC_EMI_BASE) (MEC_EMI_BASE + 5)
> +#define MEC_EMI_EC_DATA_B2(MEC_EMI_BASE) (MEC_EMI_BASE + 6)
> +#define MEC_EMI_EC_DATA_B3(MEC_EMI_BASE) (MEC_EMI_BASE + 7)
>
> -/*
> +/**
> * cros_ec_lpc_mec_init
> *
> * Initialize MEC I/O.
> + *
> + * @base: MEC EMI Base address
> + * @end: MEC EMI End address

Since you're touching this function, please fix the documentation
format also. Thanks :)

> */
> -void cros_ec_lpc_mec_init(void);
> +void cros_ec_lpc_mec_init(unsigned int base, unsigned int end);
>
> -/*
> +/**

Unrelated change.

> * cros_ec_lpc_mec_destroy
> *
> * Cleanup MEC I/O.
> */
> void cros_ec_lpc_mec_destroy(void);
>
> +/**
> + * cros_ec_lpc_mec_in_range
> + *
> + * Determine if requested addresses are in MEC EMI range.
> + *
> + * @offset: Address offset
> + * @length: Number of bytes to check
> + *
> + * @return 1 if in range, 0 if not, and -1 if there is an error
> + * such as the mec range not being initialized
> + */
> +int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length);
> +
> /**
> * cros_ec_lpc_io_bytes_mec - Read / write bytes to MEC EMI port
> *
> diff --git a/drivers/platform/chrome/cros_ec_lpc_reg.c b/drivers/platform/chrome/cros_ec_lpc_reg.c
> index fc23d535c404..4cba259b5b1e 100644
> --- a/drivers/platform/chrome/cros_ec_lpc_reg.c
> +++ b/drivers/platform/chrome/cros_ec_lpc_reg.c
> @@ -59,51 +59,32 @@ static u8 lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
>
> u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
> {
> - if (length == 0)
> - return 0;
> -
> - /* Access desired range through EMI interface */
> - if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
> - /* Ensure we don't straddle EMI region */
> - if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
> - return 0;
> + int in_range = cros_ec_lpc_mec_in_range(offset, length);
>
> - return cros_ec_lpc_io_bytes_mec(MEC_IO_READ, offset, length,
> - dest);
> - }
> -
> - if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
> - offset < MEC_EMI_RANGE_START))
> + if (in_range < 0)
> return 0;
>
> - return lpc_read_bytes(offset, length, dest);
> + return in_range ?
> + cros_ec_lpc_io_bytes_mec(MEC_IO_READ, offset, length, dest) :
> + lpc_read_bytes(offset, length, dest);
> }
>
> u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
> {
> - if (length == 0)
> - return 0;
> -
> - /* Access desired range through EMI interface */
> - if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
> - /* Ensure we don't straddle EMI region */
> - if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
> - return 0;
> + int in_range = cros_ec_lpc_mec_in_range(offset, length);
>
> - return cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, offset, length,
> - msg);
> - }
> -
> - if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
> - offset < MEC_EMI_RANGE_START))
> + if (in_range < 0)
> return 0;
>
> - return lpc_write_bytes(offset, length, msg);
> + return in_range ?
> + cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, offset, length, msg) :
> + lpc_write_bytes(offset, length, msg);
> }
>
> void cros_ec_lpc_reg_init(void)
> {
> - cros_ec_lpc_mec_init();
> + cros_ec_lpc_mec_init(EC_HOST_CMD_REGION0,
> + EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE);
> }
>
> void cros_ec_lpc_reg_destroy(void)
> --
> 2.20.0.405.gbc1bbc6f85-goog
>

Thanks,
Enric

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