[ Upstream commit 78261cb08f06c93d362cab5c5034bf5899bc7552 ]
This loop is supposed to break if the frequency returned from
clk_round_rate() is the same as on the previous iteration. However,
that check doesn't make sense on the first iteration through the loop.
It leads to reading before the start of these->clk_perf_tbl[] array.
Fixes: eddac5af06 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/8cd12678-f44a-4b16-a579-c8f11175ee8c@stanley.mountain
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4b6ea87be44ef34732846fc71e44c41125f0c4fa ]
On geni-i2c transfers using DMA, it was seen that if you program the
command (I2C_READ) before calling geni_se_rx_dma_prep() that it could
cause interrupts to fire. If we get unlucky, these interrupts can
just keep firing (and not be handled) blocking further progress and
hanging the system.
In commit 02b9aec59243 ("i2c: i2c-qcom-geni: Fix DMA transfer race")
we avoided that by making sure we didn't program the command until
after geni_se_rx_dma_prep() was called. While that avoided the
problems, it also turns out to be invalid. At least in the TX case we
started seeing sporadic corrupted transfers. This is easily seen by
adding an msleep() between the DMA prep and the writing of the
command, which makes the problem worse. That means we need to revert
that commit and find another way to fix the bogus IRQs.
Specifically, after reverting commit 02b9aec59243 ("i2c:
i2c-qcom-geni: Fix DMA transfer race"), I put some traces in. I found
that the when the interrupts were firing like crazy:
- "m_stat" had bits for M_RX_IRQ_EN, M_RX_FIFO_WATERMARK_EN set.
- "dma" was set.
Further debugging showed that I could make the problem happen more
reliably by adding an "msleep(1)" any time after geni_se_setup_m_cmd()
ran up until geni_se_rx_dma_prep() programmed the length.
A rather simple fix is to change geni_se_select_dma_mode() so it's a
true inverse of geni_se_select_fifo_mode() and disables all the FIFO
related interrupts. Now the problematic interrupts can't fire and we
can program things in the correct order without worrying.
As part of this, let's also change the writel_relaxed() in the prepare
function to a writel() so that our DMA is guaranteed to be prepared
now that we can't rely on geni_se_setup_m_cmd()'s writel().
NOTE: the only current user of GENI_SE_DMA in mainline is i2c.
Fixes: 37692de5d5 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller")
Fixes: 02b9aec59243 ("i2c: i2c-qcom-geni: Fix DMA transfer race")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201013142448.v2.1.Ifdb1b69fa3367b81118e16e9e4e63299980ca798@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 867d4aa7013fdee8b962cde1711f96c8dd86d926 ]
The geni_se_clk_freq_match() has some strange semantics. Specifically
it is defined with two modes:
1. It can find a clock that's an exact multiple of the requested rate
2. It can find a non-exact match but it can't handle multiples then
...but callers should always be able to handle a clock that is a
multiple of the requested clock so mode #2 doesn't really make sense.
Let's change the semantics so that the non-exact match can also accept
multiples and then change the code to handle that.
The only caller of this code is the unlanded SPI driver [1] which
currently passes "exact = True", thus it should be safe to change the
semantics in this way. ...and, in fact, the SPI driver should likely
be modified to pass "exact = False" (with the new semantics) since
that will allow it to work with SPI devices that request a clock rate
that doesn't exactly match a rate we can make.
[1] https://lkml.kernel.org/r/1535107336-2214-1-git-send-email-dkota@codeaurora.org
Fixes: eddac5af06 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e11bbcedecae85ce60a5d99ea03528c2d6f867e0 ]
The function clk_round_rate() is defined to return a "long", not an
"unsigned long". That's because it might return a negative error
code. Change the call in geni_se_clk_tbl_get() to check for errors.
While we're at it, get rid of a useless init of "freq".
NOTE: overall the idea that we should iterate over clk_round_rate() to
try to reconstruct a table already present in the clock driver is
questionable. Specifically:
- This method relies on "clk_round_rate()" rounding up.
- This method only works if the table is sorted and has no duplicates.
...this patch doesn't try to fix those problems, it just makes the
error handling more correct.
Fixes: eddac5af06 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This driver manages the Generic Interface (GENI) firmware based Qualcomm
Universal Peripheral (QUP) Wrapper. GENI based QUP is the next generation
programmable module composed of multiple Serial Engines (SE) and supports
a wide range of serial interfaces like UART, SPI, I2C, I3C, etc. This
driver also enables managing the serial interface independent aspects of
Serial Engines.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
