From 93ade343bbadd73999324dcc66c933e398e39818 Mon Sep 17 00:00:00 2001 From: Luben Tuikov Date: Thu, 28 Jan 2021 14:24:09 -0500 Subject: [PATCH] drm/amdgpu: EEPROM respects I2C quirks Consult the i2c_adapter.quirks table for the maximum read/write data length per bus transaction. Do not exceed this transaction limit. Cc: Jean Delvare Cc: Alexander Deucher Cc: Andrey Grodzovsky Cc: Lijo Lazar Cc: Stanley Yang Cc: Hawking Zhang Signed-off-by: Luben Tuikov Acked-by: Alexander Deucher Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c | 80 ++++++++++++++++++++++++------ 1 file changed, 64 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c index 7fdb5bd..94aeda1 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c @@ -32,20 +32,9 @@ #define EEPROM_OFFSET_SIZE 2 -/** - * amdgpu_eeprom_xfer -- Read/write from/to an I2C EEPROM device - * @i2c_adap: pointer to the I2C adapter to use - * @slave_addr: I2C address of the slave device - * @eeprom_addr: EEPROM address from which to read/write - * @eeprom_buf: pointer to data buffer to read into/write from - * @buf_size: the size of @eeprom_buf - * @read: True if reading from the EEPROM, false if writing - * - * Returns the number of bytes read/written; -errno on error. - */ -int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, - u16 slave_addr, u16 eeprom_addr, - u8 *eeprom_buf, u16 buf_size, bool read) +static int __amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, + u16 slave_addr, u16 eeprom_addr, + u8 *eeprom_buf, u16 buf_size, bool read) { u8 eeprom_offset_buf[EEPROM_OFFSET_SIZE]; struct i2c_msg msgs[] = { @@ -65,8 +54,8 @@ int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, u16 len; r = 0; - for (len = 0; buf_size > 0; - buf_size -= len, eeprom_addr += len, eeprom_buf += len) { + for ( ; buf_size > 0; + buf_size -= len, eeprom_addr += len, eeprom_buf += len) { /* Set the EEPROM address we want to write to/read from. */ msgs[0].buf[0] = (eeprom_addr >> 8) & 0xff; @@ -120,3 +109,62 @@ int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, return r < 0 ? r : eeprom_buf - p; } + +/** + * amdgpu_eeprom_xfer -- Read/write from/to an I2C EEPROM device + * @i2c_adap: pointer to the I2C adapter to use + * @slave_addr: I2C address of the slave device + * @eeprom_addr: EEPROM address from which to read/write + * @eeprom_buf: pointer to data buffer to read into/write from + * @buf_size: the size of @eeprom_buf + * @read: True if reading from the EEPROM, false if writing + * + * Returns the number of bytes read/written; -errno on error. + */ +int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, + u16 slave_addr, u16 eeprom_addr, + u8 *eeprom_buf, u16 buf_size, bool read) +{ + const struct i2c_adapter_quirks *quirks = i2c_adap->quirks; + u16 limit; + + if (!quirks) + limit = 0; + else if (read) + limit = quirks->max_read_len; + else + limit = quirks->max_write_len; + + if (limit == 0) { + return __amdgpu_eeprom_xfer(i2c_adap, slave_addr, eeprom_addr, + eeprom_buf, buf_size, read); + } else if (limit <= EEPROM_OFFSET_SIZE) { + dev_err_ratelimited(&i2c_adap->dev, + "maddr:0x%04X size:0x%02X:quirk max_%s_len must be > %d", + eeprom_addr, buf_size, + read ? "read" : "write", EEPROM_OFFSET_SIZE); + return -EINVAL; + } else { + u16 ps; /* Partial size */ + int res = 0, r; + + /* The "limit" includes all data bytes sent/received, + * which would include the EEPROM_OFFSET_SIZE bytes. + * Account for them here. + */ + limit -= EEPROM_OFFSET_SIZE; + for ( ; buf_size > 0; + buf_size -= ps, eeprom_addr += ps, eeprom_buf += ps) { + ps = min(limit, buf_size); + + r = __amdgpu_eeprom_xfer(i2c_adap, + slave_addr, eeprom_addr, + eeprom_buf, ps, read); + if (r < 0) + return r; + res += r; + } + + return res; + } +} -- 2.7.4