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authorDaniel Golle <daniel@makrotopia.org>2019-06-12 01:14:25 +0200
committerDaniel Golle <daniel@makrotopia.org>2019-06-12 01:18:52 +0200
commit000d400baa0af2e42c9a462e42df7dc9abde1ec7 (patch)
treea11c2dd570e8f02c4a141f135fc8db1e1d391ef2 /target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch
parentc4e727f01cc40bd57274d0b885b0f75cde9c4683 (diff)
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kernel: drop everything not on kernel version 4.14
* Remove testing patches for kernel version 4.19 * remove targets ar7, ixp4xx, orion Those targets are still on kernel 4.9, patches for 4.14 were not ready in time. They may be readded once people prepare and test patches for kernel 4.14. Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Diffstat (limited to 'target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch')
-rw-r--r--target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch77
1 files changed, 0 insertions, 77 deletions
diff --git a/target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch b/target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch
deleted file mode 100644
index 9e8c331934..0000000000
--- a/target/linux/tegra/patches-4.19/100-serial8250-on-tegra-hsuart-recover-from-spurious-interrupts-due-to-tegra2-silicon-bug.patch
+++ /dev/null
@@ -1,77 +0,0 @@
-From patchwork Fri Jul 13 11:32:42 2018
-Content-Type: text/plain; charset="utf-8"
-MIME-Version: 1.0
-Content-Transfer-Encoding: 7bit
-Subject: serial8250 on tegra hsuart: recover from spurious interrupts due to
- tegra2 silicon bug
-X-Patchwork-Submitter: "David R. Piegdon" <lkml@p23q.org>
-X-Patchwork-Id: 943440
-Message-Id: <4676ea34-69ce-5422-1ded-94218b89f7d9@p23q.org>
-To: linux-tegra@vger.kernel.org
-Date: Fri, 13 Jul 2018 11:32:42 +0000
-From: "David R. Piegdon" <lkml@p23q.org>
-List-Id: <linux-tegra.vger.kernel.org>
-
-Hi,
-a while back I sent a few mails regarding spurious interrupts in the
-UARTA (hsuart) block of the Tegra2 SoC, when using the 8250 driver for
-it instead of the hsuart driver. After going down a pretty deep
-debugging/testing hole, I think I found a patch that fixes the issue. So
-far testing in a reboot-cycle suggests that the error frequency dropped
-from >3% of all reboots to at least <0.05% of all reboots. Tests
-continue to run over the weekend.
-
-The patch below already is a second iteration; the first did not reset
-the MCR or contain the lines below '// clear interrupts'. This resulted
-in no more spurious interrupts, but in a few % of spurious interrupts
-that were recovered the UART block did not receive any characters any
-more. So further resetting was required to fully reacquire operational
-state of the UART block.
-
-I'd love any comments/suggestions on this!
-
-Cheers,
-
-David
-
---- a/drivers/tty/serial/8250/8250_core.c
-+++ b/drivers/tty/serial/8250/8250_core.c
-@@ -136,6 +136,38 @@ static irqreturn_t serial8250_interrupt(
- "serial8250: too much work for irq%d\n", irq);
- break;
- }
-+
-+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
-+ if (!handled && (port->type == PORT_TEGRA)) {
-+ /*
-+ * Fix Tegra 2 CPU silicon bug where sometimes
-+ * "TX holding register empty" interrupts result in a
-+ * bad (metastable?) state in Tegras HSUART IP core.
-+ * Only way to recover seems to be to reset all
-+ * interrupts as well as the TX queue and the MCR.
-+ * But we don't want to loose any outgoing characters,
-+ * so only do it if the RX and TX queues are empty.
-+ */
-+ unsigned char lsr = port->serial_in(port, UART_LSR);
-+ const unsigned char fifo_empty_mask =
-+ (UART_LSR_TEMT | UART_LSR_THRE);
-+ if (((lsr & (UART_LSR_DR | fifo_empty_mask)) ==
-+ fifo_empty_mask)) {
-+ port->serial_out(port, UART_IER, 0);
-+ port->serial_out(port, UART_MCR, 0);
-+ serial8250_clear_and_reinit_fifos(up);
-+ port->serial_out(port, UART_MCR, up->mcr);
-+ port->serial_out(port, UART_IER, up->ier);
-+ // clear interrupts
-+ serial_port_in(port, UART_LSR);
-+ serial_port_in(port, UART_RX);
-+ serial_port_in(port, UART_IIR);
-+ serial_port_in(port, UART_MSR);
-+ up->lsr_saved_flags = 0;
-+ up->msr_saved_flags = 0;
-+ }
-+ }
-+#endif
- } while (l != end);
-
- spin_unlock(&i->lock);