drivers: ddr: imx8mp: Add inline ECC feature support

the DRAM Controller in i.MX8MP will support a feature called "Inline ECC".
This is supported for all 3 supported DRAM technologies (LPDDR4, DDR4 and
DDR3L). When this feature is enabled by software, the DRAM Controller
reserves 12.5% of DRAM capacity for ECC information, and presents only
the non-ECC portion (lower 87.5% of the installed capacity of DRAM) to
the rest of the SoC.
The DRAM memory can be divided into 8 regions so that if a use case only
requires ECC protection on a subset of memory, then only that subset of
memory need support inline ECC. If this occurs, then there is no
performance penalty accessing the non-ECC-protected memory (no need to
access ECC for this portion of the memory map). This is all configured
with the DRAM Controller.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

2 files changed, 79 insertions, 0 deletions

diff --git a/drivers/ddr/imx/imx8m/Kconfig b/drivers/ddr/imx/imx8m/Kconfig
index 5bf61eb2587..a5f5524fbec 100644
--- a/drivers/ddr/imx/imx8m/Kconfig
+++ b/drivers/ddr/imx/imx8m/Kconfig
@@ -29,4 +29,11 @@ config SAVED_DRAM_TIMING_BASE
 	  info into memory for low power use. OCRAM_S is used for this
 	  purpose on i.MX8MM.
 	default 0x180000
+
+config IMX8M_DRAM_INLINE_ECC
+	bool "imx8mp inline ECC"
+	depends on IMX8MP && IMX8M_LPDDR4
+	help
+	  Select this config if you want to use inline ecc feature for
+	  imx8mp-evk board.
 endmenu
diff --git a/drivers/ddr/imx/imx8m/ddr_init.c b/drivers/ddr/imx/imx8m/ddr_init.c
index de302937d08..664966c41bf 100644
--- a/drivers/ddr/imx/imx8m/ddr_init.c
+++ b/drivers/ddr/imx/imx8m/ddr_init.c
@@ -21,6 +21,76 @@ void ddr_cfg_umctl2(struct dram_cfg_param *ddrc_cfg, int num)
 	}
 }
 
+#ifdef CONFIG_IMX8M_DRAM_INLINE_ECC
+void ddrc_inline_ecc_scrub(unsigned int start_address,
+			   unsigned int range_address)
+{
+	unsigned int tmp;
+
+	/* Step1: Enable quasi-dynamic programming */
+	reg32_write(DDRC_SWCTL(0), 0x00000000);
+	/* Step2: Set ECCCFG1.ecc_parity_region_lock to 1 */
+	reg32setbit(DDRC_ECCCFG1(0), 0x4);
+	/* Step3: Block the AXI ports from taking the transaction */
+	reg32_write(DDRC_PCTRL_0(0), 0x0);
+	/* Step4: Set scrub start address */
+	reg32_write(DDRC_SBRSTART0(0), start_address);
+	/* Step5: Set scrub range address */
+	reg32_write(DDRC_SBRRANGE0(0), range_address);
+	/* Step6: Set scrub_mode to write */
+	reg32_write(DDRC_SBRCTL(0), 0x00000014);
+	/* Step7: Set the desired pattern through SBRWDATA0 registers */
+	reg32_write(DDRC_SBRWDATA0(0), 0x55aa55aa);
+	/* Step8: Enable the SBR by programming SBRCTL.scrub_en=1 */
+	reg32setbit(DDRC_SBRCTL(0), 0x0);
+	/* Step9: Poll SBRSTAT.scrub_done=1 */
+	tmp = reg32_read(DDRC_SBRSTAT(0));
+	while (tmp != 0x00000002)
+		tmp = reg32_read(DDRC_SBRSTAT(0)) & 0x2;
+	/* Step10: Poll SBRSTAT.scrub_busy=0 */
+	tmp = reg32_read(DDRC_SBRSTAT(0));
+	while (tmp != 0x0)
+		tmp = reg32_read(DDRC_SBRSTAT(0)) & 0x1;
+	/* Step11: Disable SBR by programming SBRCTL.scrub_en=0 */
+	clrbits_le32(DDRC_SBRCTL(0), 0x1);
+	/* Step12: Prepare for normal scrub operation(Read) and set scrub_interval*/
+	reg32_write(DDRC_SBRCTL(0), 0x100);
+	/* Step13: Enable the SBR by programming SBRCTL.scrub_en=1 */
+	reg32_write(DDRC_SBRCTL(0), 0x101);
+	/* Step14: Enable AXI ports by programming */
+	reg32_write(DDRC_PCTRL_0(0), 0x1);
+	/* Step15: Disable quasi-dynamic programming */
+	reg32_write(DDRC_SWCTL(0), 0x00000001);
+}
+
+void ddrc_inline_ecc_scrub_end(unsigned int start_address,
+			       unsigned int range_address)
+{
+	/* Step1: Enable quasi-dynamic programming */
+	reg32_write(DDRC_SWCTL(0), 0x00000000);
+	/* Step2: Block the AXI ports from taking the transaction */
+	reg32_write(DDRC_PCTRL_0(0), 0x0);
+	/* Step3: Set scrub start address */
+	reg32_write(DDRC_SBRSTART0(0), start_address);
+	/* Step4: Set scrub range address */
+	reg32_write(DDRC_SBRRANGE0(0), range_address);
+	/* Step5: Disable SBR by programming SBRCTL.scrub_en=0 */
+	clrbits_le32(DDRC_SBRCTL(0), 0x1);
+	/* Step6: Prepare for normal scrub operation(Read) and set scrub_interval */
+	reg32_write(DDRC_SBRCTL(0), 0x100);
+	/* Step7: Enable the SBR by programming SBRCTL.scrub_en=1 */
+	reg32_write(DDRC_SBRCTL(0), 0x101);
+	/* Step8: Enable AXI ports by programming */
+	reg32_write(DDRC_PCTRL_0(0), 0x1);
+	/* Step9: Disable quasi-dynamic programming */
+	reg32_write(DDRC_SWCTL(0), 0x00000001);
+}
+#endif
+
+void __weak board_dram_ecc_scrub(void)
+{
+}
+
 int ddr_init(struct dram_timing_info *dram_timing)
 {
 	unsigned int tmp, initial_drate, target_freq;
@@ -169,6 +239,8 @@ int ddr_init(struct dram_timing_info *dram_timing)
 	reg32_write(DDRC_PCTRL_0(0), 0x00000001);
 	debug("DDRINFO: ddrmix config done\n");
 
+	board_dram_ecc_scrub();
+
 	/* save the dram timing config into memory */
 	dram_config_save(dram_timing, CONFIG_SAVED_DRAM_TIMING_BASE);