Re: [PATCH V4 2/4] arm64: imx8mp: Read values from M24C32-D write-lockable page on DHCOM i.MX8MP

On 11/28/24 3:20 PM, Christoph Niedermaier wrote:

[...]

+++ b/board/dhelectronics/common/dh_common.c @@ -7,6 +7,7 @@ #include <dm.h> #include <i2c_eeprom.h> #include <net.h> +#include <u-boot/crc.h>

#include "dh_common.h"

@@ -30,6 +31,148 @@ int dh_get_mac_is_enabled(const char *alias) return 0; }

+int dh_read_eeprom_id_page(u8 *eeprom_buffer, const char *alias) +{

• struct eeprom_id_page *eip = (struct eeprom_id_page *)eeprom_buffer;
• struct udevice *dev;
• size_t payload_len;
• int eeprom_size;
• u16 crc16_calc;
• u16 crc16_eip;
• u8 crc8_calc;
• ofnode node;
• int ret;
• node = ofnode_path(alias);
• ret = uclass_get_device_by_ofnode(UCLASS_I2C_EEPROM, node, &dev);
• if (ret)

• return ret;
  

• eeprom_size = i2c_eeprom_size(dev);
• if (eeprom_size < 0) {

• printf("%s: Error getting EEPROM ID page size! ret = %d\n", __func__, ret);
  

• return eeprom_size;
  

• } else if (eeprom_size == 0 || eeprom_size > DH_EEPROM_ID_PAGE_MAX_SIZE) {

The else part is not necessary, use plain:

... ... return eeprom_size; }

if (eeprom_size == 0 || eeprom_size > DH_EEPROM_ID_PAGE_MAX_SIZE) { ...

• eeprom_size = DH_EEPROM_ID_PAGE_MAX_SIZE;
  

• printf("Get invalid EEPROM ID page size %d bytes! Try to read %d bytes.\n",
  

•        eeprom_size, DH_EEPROM_ID_PAGE_MAX_SIZE);
  

• }
• ret = i2c_eeprom_read(dev, 0x0, eeprom_buffer, eeprom_size);
• if (ret) {

• printf("%s: Error reading EEPROM ID page! ret = %d\n", __func__, ret);
  

• return ret;
  

• }
• /* Validate header ID */
• if (eip->hdr.id[0] != 'D' || eip->hdr.id[1] != 'H' || eip->hdr.id[2] != 'E') {

• printf("%s: Error validating header ID! (got %c%c%c (0x%02x 0x%02x 0x%02x) != expected DHE)\n",
  

•        __func__, isprint(eip->hdr.id[0]) ? eip->hdr.id[0] : '.',
  

•        isprint(eip->hdr.id[1]) ? eip->hdr.id[1] : '.',
  

•        isprint(eip->hdr.id[2]) ? eip->hdr.id[2] : '.',
  

•        eip->hdr.id[0], eip->hdr.id[1], eip->hdr.id[2]);
  

• return -EINVAL;
  

• }
• /* Validate header checksum */
• crc8_calc = crc8(0xff, eeprom_buffer, offsetof(struct eeprom_id_page, hdr.crc8_hdr));
• if (eip->hdr.crc8_hdr != crc8_calc) {

• printf("%s: Error validating header checksum! (got 0x%02x != calc 0x%02x)\n",
  

•        __func__, eip->hdr.crc8_hdr, crc8_calc);
  

• return -EINVAL;
  

• }
• /*

• * Validate header version
  

• * The payload is defined by the version specified in the header.
  

• * Currently only version 0x10 is defined, so take the length of
  

• * the only defined payload as the payload length.
  

• */
  

• if (eip->hdr.version == DH_EEPROM_ID_PAGE_V1_0) {

Invert this conditional:

... if (eip->hdr.version != DH_EEPROM_ID_PAGE_V1_0) { printf(...); return ...; }

payload_len = sizeof(eip->pl); ...

• payload_len = sizeof(eip->pl);
  

• } else {

• printf("%s: Error validating version! (0x%02X is not supported)\n",
  

•        __func__, eip->hdr.version);
  

• return -EINVAL;
  

• }
• /* Validate payload checksum */
• crc16_eip = (eip->hdr.crc16_pl[1] << 8) | eip->hdr.crc16_pl[0];
• crc16_calc = crc16(0xffff, eeprom_buffer + sizeof(eip->hdr), payload_len);
• if (crc16_eip != crc16_calc) {

• printf("%s: Error validating data checksum! (got 0x%02x != calc 0x%02x)\n",
  

•        __func__, crc16_eip, crc16_calc);
  

• return -EINVAL;
  

• }
• return 0;

+}

[...]