intel/common/smbus: increase spd read performance
This change increases the spd read performance by using smbus word access. BUG=b:67021853 TEST=boot to os and find 80~100 ms boot time improvement on one dimm Change-Id: I98fe67642d8ccd428bccbca7f6390331d6055d14 Signed-off-by: Kane Chen <kane.chen@intel.com> Reviewed-on: https://review.coreboot.org/22072 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
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@ -1212,6 +1212,9 @@ config DIMM_SPD_SIZE
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Total SPD size that will be used for DIMM.
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Ex: DDR3 256, DDR4 512.
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config SPD_READ_BY_WORD
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bool
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config BOARD_ID_AUTO
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bool
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default n
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@ -63,6 +63,7 @@ void smbus_reset(u32 smbus_dev);
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int smbus_print_error(u32 smbus_dev, u8 host_status, int loops);
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int smbus_is_busy(u32 smbus_dev);
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int smbus_wait_until_ready(u32 smbus_dev);
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u16 smbus_read_word(u32 smbus_dev, u8 addr, u8 offset);
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u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset);
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u8 smbus_write_byte(u32 smbus_dev, u8 addr, u8 offset, u8 value);
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void smbus_delay(void);
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@ -125,26 +125,40 @@ int get_spd_cbfs_rdev(struct region_device *spd_rdev, u8 spd_index)
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CONFIG_DIMM_SPD_SIZE);
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}
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static void get_spd(u8 *spd, u8 addr)
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static void smbus_read_spd(u8 *spd, u8 addr)
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{
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u16 i;
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if (smbus_read_byte(0, addr, 0) == 0xff) {
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u8 step = 1;
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if (IS_ENABLED(CONFIG_SPD_READ_BY_WORD))
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step = sizeof(uint16_t);
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for (i = 0; i < SPD_PAGE_LEN; i += step) {
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if (IS_ENABLED(CONFIG_SPD_READ_BY_WORD))
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((u16*)spd)[i / sizeof(uint16_t)] =
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smbus_read_word(0, addr, i);
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else
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spd[i] = smbus_read_byte(0, addr, i);
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}
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}
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static void get_spd(u8 *spd, u8 addr)
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{
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if (smbus_read_byte(0, addr, 0) == 0xff) {
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printk(BIOS_INFO, "No memory dimm at address %02X\n",
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addr << 1);
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/* Make sure spd is zeroed if dimm doesn't exist. */
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memset(spd, 0, CONFIG_DIMM_SPD_SIZE);
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return;
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}
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smbus_read_spd(spd, addr);
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for (i = 0; i < SPD_PAGE_LEN; i++)
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spd[i] = smbus_read_byte(0, addr, i);
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/* Check if module is DDR4, DDR4 spd is 512 byte. */
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if (spd[SPD_DRAM_TYPE] == SPD_DRAM_DDR4 &&
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CONFIG_DIMM_SPD_SIZE >= SPD_DRAM_DDR4) {
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CONFIG_DIMM_SPD_SIZE > SPD_PAGE_LEN) {
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/* Switch to page 1 */
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smbus_write_byte(0, SPD_PAGE_1, 0, 0);
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for (i = 0; i < SPD_PAGE_LEN; i++)
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spd[i+SPD_PAGE_LEN] = smbus_read_byte(0, addr, i);
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smbus_read_spd(spd + SPD_PAGE_LEN, addr);
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/* Restore to page 0 */
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smbus_write_byte(0, SPD_PAGE_0, 0, 0);
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}
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@ -36,6 +36,11 @@ static const struct reg_script smbus_init_script[] = {
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REG_SCRIPT_END,
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};
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u16 smbus_read_word(u32 smbus_dev, u8 addr, u8 offset)
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{
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return smbus_read16(SMBUS_IO_BASE, addr, offset);
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}
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u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset)
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{
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return smbus_read8(SMBUS_IO_BASE, addr, offset);
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@ -135,3 +135,44 @@ int smbus_write8(unsigned int smbus_base, unsigned int device,
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return 0;
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}
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int smbus_read16(unsigned int smbus_base, unsigned int device,
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unsigned int address)
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{
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unsigned char global_status_register;
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unsigned short data;
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if (smbus_wait_till_ready(smbus_base) < 0)
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return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
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/* Set up transaction */
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/* Disable interrupts */
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outb(inb(smbus_base + SMBHSTCTL) & ~1, smbus_base + SMBHSTCTL);
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/* Set the device I'm talking to */
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outb(((device & 0x7f) << 1) | 1, smbus_base + SMBXMITADD);
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/* Set the command/address... */
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outb(address & 0xff, smbus_base + SMBHSTCMD);
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/* Set up for a word data read */
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outb((inb(smbus_base + SMBHSTCTL) & 0xe3) | (0x3 << 2),
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(smbus_base + SMBHSTCTL));
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/* Clear any lingering errors, so the transaction will run */
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outb(inb(smbus_base + SMBHSTSTAT), smbus_base + SMBHSTSTAT);
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/* Start the command */
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outb((inb(smbus_base + SMBHSTCTL) | 0x40),
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smbus_base + SMBHSTCTL);
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/* Poll for transaction completion */
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if (smbus_wait_till_done(smbus_base) < 0)
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return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
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global_status_register = inb(smbus_base + SMBHSTSTAT);
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/* Ignore the "In Use" status... */
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if ((global_status_register & ~(3 << 5)) != (1 << 1))
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return SMBUS_ERROR;
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/* Read results of transaction */
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data = inw(smbus_base + SMBHSTDAT0);
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return data;
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}
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@ -34,5 +34,7 @@ int smbus_read8(unsigned int smbus_base, unsigned int device,
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unsigned int address);
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int smbus_write8(unsigned int smbus_base, unsigned int device,
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unsigned int address, unsigned int data);
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int smbus_read16(unsigned int smbus_base, unsigned int device,
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unsigned int address);
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#endif /* SOC_INTEL_COMMON_BLOCK_SMBUS__LIB_H */
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