FAILED: patch "[PATCH] mtd: rawnand: gpmi: Set WAIT_FOR_READY timeout based on" failed to apply to 5.4-stable tree

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0fddf9ad06fd9f439f137139861556671673e31c Mon Sep 17 00:00:00 2001
From: Sascha Hauer <[email protected]>
Date: Fri, 1 Jul 2022 13:03:41 +0200
Subject: [PATCH] mtd: rawnand: gpmi: Set WAIT_FOR_READY timeout based on
program/erase times
MIME-Version: 1.0
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06781a5026350 Fixes the calculation of the DEVICE_BUSY_TIMEOUT register value from busy_timeout_cycles. busy_timeout_cycles is calculated wrong
though: It is calculated based on the maximum page read time, but the timeout is also used for page write and block erase operations which require orders of magnitude bigger timeouts.

Fix this by calculating busy_timeout_cycles from the maximum of tBERS_max and tPROG_max.

This is for now the easiest and most obvious way to fix the driver. There's room for improvements though: The NAND_OP_WAITRDY_INSTR tells us the desired timeout for the current operation, so we could program the timeout dynamically for each operation instead of setting a fixed timeout. Also we could wire up the interrupt handler to actually detect and forward timeouts occurred when waiting for the chip being ready.

As a sidenote I verified that the change in 06781a5026350 is really correct. I wired up the interrupt handler in my tree and measured the time between starting the operation and the timeout interrupt handler coming in. The time increases 41us with each step in the timeout register which corresponds to 4096 clock cycles with the 99MHz clock that I have.

index 889e40329956..93da23682d86 100644
@@ -850,9 +850,10 @@ static int gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 	unsigned int tRP_ps;
 	bool use_half_period;
 	int sample_delay_ps, sample_delay_factor;
-	u16 busy_timeout_cycles;
+	unsigned int busy_timeout_cycles;
 	u8 wrn_dly_sel;
 	unsigned long clk_rate, min_rate;
+	u64 busy_timeout_ps;
 
 	if (sdr->tRC_min >= 30000) {
 		/* ONFI non-EDO modes [0-3] */

@@ -885,7 +886,8 @@ static int gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 	addr_setup_cycles = TO_CYCLES(sdr->tALS_min, period_ps);
 	data_setup_cycles = TO_CYCLES(sdr->tDS_min, period_ps);
 	data_hold_cycles = TO_CYCLES(sdr->tDH_min, period_ps);
-	busy_timeout_cycles = TO_CYCLES(sdr->tWB_max + sdr->tR_max, period_ps);
+	busy_timeout_ps = max(sdr->tBERS_max, sdr->tPROG_max);
+	busy_timeout_cycles = TO_CYCLES(busy_timeout_ps, period_ps);
 
 	hw->timing0 = BF_GPMI_TIMING0_ADDRESS_SETUP(addr_setup_cycles) |
 		      BF_GPMI_TIMING0_DATA_HOLD(data_hold_cycles) |