[PATCH 1/4] clk: meson: t7: keep the memory fabric clocks running

[Lucas Tanure]

Four clocks feed the bus that moves data between the peripherals and
memory. Nothing in Linux claims them, so they were switched off shortly
after boot, and any device that started a transfer after that point
simply stopped. The SD card, which comes up about two seconds in, never
finished reading its identification.

There is no device these clocks belong to, so mark them as always
needed.

Fixes: fab4d651b592 ("clk: meson: t7: add t7 clock peripherals controller driver")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Lucas Tanure <tanure at linux.com>
---
 drivers/clk/meson/t7-peripherals.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/meson/t7-peripherals.c b/drivers/clk/meson/t7-peripherals.c
index 214db7850d86..55d09e78593b 100644
--- a/drivers/clk/meson/t7-peripherals.c
+++ b/drivers/clk/meson/t7-peripherals.c
@@ -945,11 +945,16 @@ static T7_SYS_PCLK(sys_aucpu,		SYS_CLK_EN0_REG0, 14,	0);
 static T7_SYS_PCLK(sys_cec,		SYS_CLK_EN0_REG0, 16,	0);
 static T7_SYS_PCLK(sys_gdc,		SYS_CLK_EN0_REG0, 17,	0);
 static T7_SYS_PCLK(sys_deswarp,		SYS_CLK_EN0_REG0, 18,	0);
-static T7_SYS_PCLK(sys_ampipe_nand,	SYS_CLK_EN0_REG0, 19,	0);
+/*
+ * NOTE: sys_ampipe_nand and sys_am2axi0..2 provide the clock to the AXI bus
+ * used for DMA between the peripherals and the DRAM. After the clocks are
+ * disabled, a device that starts a transfer cannot complete it.
+ */
+static T7_SYS_PCLK(sys_ampipe_nand,	SYS_CLK_EN0_REG0, 19,	CLK_IS_CRITICAL);
 static T7_SYS_PCLK(sys_ampipe_eth,	SYS_CLK_EN0_REG0, 20,	0);
-static T7_SYS_PCLK(sys_am2axi0,		SYS_CLK_EN0_REG0, 21,	0);
-static T7_SYS_PCLK(sys_am2axi1,		SYS_CLK_EN0_REG0, 22,	0);
-static T7_SYS_PCLK(sys_am2axi2,		SYS_CLK_EN0_REG0, 23,	0);
+static T7_SYS_PCLK(sys_am2axi0,		SYS_CLK_EN0_REG0, 21,	CLK_IS_CRITICAL);
+static T7_SYS_PCLK(sys_am2axi1,		SYS_CLK_EN0_REG0, 22,	CLK_IS_CRITICAL);
+static T7_SYS_PCLK(sys_am2axi2,		SYS_CLK_EN0_REG0, 23,	CLK_IS_CRITICAL);
 static T7_SYS_PCLK(sys_sd_emmc_a,	SYS_CLK_EN0_REG0, 24,	0);
 static T7_SYS_PCLK(sys_sd_emmc_b,	SYS_CLK_EN0_REG0, 25,	0);
 static T7_SYS_PCLK(sys_sd_emmc_c,	SYS_CLK_EN0_REG0, 26,	0);
-- 
2.55.0